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Ferland S, Wang F, De Koninck Y, Ferrini F. An improved conflict avoidance assay reveals modality-specific differences in pain hypersensitivity across sexes. Pain 2024; 165:1304-1316. [PMID: 38277178 PMCID: PMC11090034 DOI: 10.1097/j.pain.0000000000003132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 10/17/2023] [Accepted: 11/06/2023] [Indexed: 01/27/2024]
Abstract
ABSTRACT Abnormal encoding of somatosensory modalities (ie, mechanical, cold, and heat) are a critical part of pathological pain states. Detailed phenotyping of patients' responses to these modalities have raised hopes that analgesic treatments could one day be tailored to a patient's phenotype. Such precise treatment would require a profound understanding of the underlying mechanisms of specific pain phenotypes at molecular, cellular, and circuitry levels. Although preclinical pain models have helped in that regard, the lack of a unified assay quantifying detailed mechanical, cold, and heat pain responses on the same scale precludes comparing how analgesic compounds act on different sensory phenotypes. The conflict avoidance assay is promising in that regard, but testing conditions require validation for its use with multiple modalities. In this study, we improve upon the conflict avoidance assay to provide a validated and detailed assessment of all 3 modalities within the same animal, in mice. We first optimized testing conditions to minimize the necessary amount of training and to reduce sex differences in performances. We then tested what range of stimuli produce dynamic stimulus-response relationships for different outcome measures in naive mice. We finally used this assay to show that nerve injury produces modality-specific sex differences in pain behavior. Our improved assay opens new avenues to study the basis of modality-specific abnormalities in pain behavior.
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Affiliation(s)
| | - Feng Wang
- CERVO Brain Research Centre, Québec, QC, Canada
- Faculty of Dentistry, Université Laval, Québec, QC, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Québec, QC, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
| | - Francesco Ferrini
- CERVO Brain Research Centre, Québec, QC, Canada
- Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
- Department of Veterinary Sciences, University of Turin, Turin, Italy
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2
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Dayton JR, Marquez J, Romo AK, Chen YJ, Contreras JE, Griffith TN. Thermal escape box: A cost-benefit evaluation paradigm for investigating thermosensation and thermal pain. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2024; 15:100155. [PMID: 38617105 PMCID: PMC11015515 DOI: 10.1016/j.ynpai.2024.100155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/18/2024] [Accepted: 03/27/2024] [Indexed: 04/16/2024]
Abstract
Thermosensation, the ability to detect and estimate temperature, is an evolutionarily conserved process that is essential for survival. Thermosensing is impaired in various pain syndromes, resulting in thermal allodynia, the perception of an innocuous temperature as painful, or thermal hyperalgesia, an exacerbated perception of a painful thermal stimulus. Several behavioral assays exist to study thermosensation and thermal pain in rodents, however, most rely on reflexive withdrawal responses or the subjective quantification of spontaneous nocifensive behaviors. Here, we created a new apparatus, the thermal escape box, which can be attached to temperature-controlled plates and used to assess temperature-dependent effort-based decision-making. The apparatus consists of a light chamber with an opening that fits around temperature-controlled plates, and a small entryway into a dark chamber. A mouse must choose to stay in a brightly lit aversive area or traverse the plates to escape to the enclosed dark chamber. We quantified escape latencies of adult C57Bl/6 mice at different plate temperatures from video recordings and found they were significantly longer at 5 °C, 18 °C, and 52 °C, compared to 30 °C, a mouse's preferred ambient temperature. Differences in escape latencies were abolished in male Trpm8-/- mice and in male Trpv1-/- animals. Finally, we show that chronic constriction injury procedures or oxaliplatin treatement significantly increased escape latencies at cold temperatures compared to controls, the later of which was prevented by the analgesic meloxicam. This demonstrates the utility of this assay in detecting cold pain. Collectively, our study has identified a new and effective tool that uses cost-benefit valuations to study thermosensation and thermal pain.
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Affiliation(s)
- Jacquelyn R. Dayton
- University of California, Davis. Department of Physiology & Membrane Biology, 1275 Med Science Drive, Davis, CA 95616, United States
| | - Jose Marquez
- University of California, Davis. Department of Physiology & Membrane Biology, 1275 Med Science Drive, Davis, CA 95616, United States
| | - Alejandra K. Romo
- University of California, Davis. Department of Physiology & Membrane Biology, 1275 Med Science Drive, Davis, CA 95616, United States
| | - Yi-Je Chen
- University of California, Davis. Department of Pharmacology, 1275 Med Science Drive, Davis, CA 95616, United States
| | - Jorge E. Contreras
- University of California, Davis. Department of Physiology & Membrane Biology, 1275 Med Science Drive, Davis, CA 95616, United States
| | - Theanne N. Griffith
- University of California, Davis. Department of Physiology & Membrane Biology, 1275 Med Science Drive, Davis, CA 95616, United States
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3
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Marques DP, Chacur M, Martins DO. Photobiomodulation and vitamin B treatment alleviate both thermal and mechanical orofacial pain in rats. Photochem Photobiol Sci 2023; 22:2315-2327. [PMID: 37340216 DOI: 10.1007/s43630-023-00452-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023]
Abstract
PURPOSE The present study investigates the efficacy of Photobiomodulation (PBM) and Vitamin B Complex (VBC) to relieve pain, both in separately and combined (PBM and VBC). METHODS Rats with chronic constriction injury of the right infraorbital nerve (CCI-IoN) or Sham surgery were used. PBM was administered at a wavelength of 904 nm and energy density of 6.23 J/cm2 and VBC (containing B1, B6 and B12) subcutaneously, both separately and combined. Behavioral tests were performed to assess mechanical and thermal hypersensitivity before and after CCI and after PBM, VBC, or PBM + VBC. The expression of inflammatory proteins in the trigeminal ganglion and the immunohistochemical alterations of Periaqueductal Gray (PAG) astrocytes and microglia were examined following CCI and treatments. RESULTS All testeds treatments reversed the painful behavior. The decrease in pain was accompanied by a decrease of Glial Fibrillary Acidic Protein (GFAP), a specific astrocytic marker, and Ionized calcium-binding adaptor molecule 1 (Iba-1), a marker of microglia, and decreased expression of Transient Receptor Potential Vanilloid 1 (TRPV1), Substance P, and Calcitonin Gene-Related Peptide (CGRP) induced by CCI-IoN in PAG and Trigeminal ganglion. Furthermore, both treatments showed a higher expression of Cannabinoid-type 1 (CB1) receptor in the trigeminal ganglion compared to CCI-IoN rats. Our results show that no difference was observed between groups. CONCLUSION We showed that PBM or VBC regulates neuroinflammation and reduces inflammatory protein expression. However, the combination of PBM and VBC did not enhance the effectiveness of both therapies alone.
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Affiliation(s)
- Daniel Pereira Marques
- Departamento de Anatomia, Laboratory of Functional Neuroanatomy of Pain, Universidade de São Paulo Instituto de Ciências Biomédicas, São Paulo, São Paulo, Brazil
| | - Marucia Chacur
- Departamento de Anatomia, Laboratory of Functional Neuroanatomy of Pain, Universidade de São Paulo Instituto de Ciências Biomédicas, São Paulo, São Paulo, Brazil
| | - Daniel Oliveira Martins
- Departamento de Anatomia, Laboratory of Functional Neuroanatomy of Pain, Universidade de São Paulo Instituto de Ciências Biomédicas, São Paulo, São Paulo, Brazil.
- Division of Neuroscience/Hospital Sírio-Libânes, Street Daher Cutait, 69, São Paulo, São Paulo, 01308-060, Brazil.
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Leite-Panissi CRA, De Paula BB, Neubert JK, Caudle RM. Influence of TRPV1 on Thermal Nociception in Rats with Temporomandibular Joint Persistent Inflammation Evaluated by the Operant Orofacial Pain Assessment Device (OPAD). J Pain Res 2023; 16:2047-2062. [PMID: 37342611 PMCID: PMC10278653 DOI: 10.2147/jpr.s405258] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/05/2023] [Indexed: 06/23/2023] Open
Abstract
Background Temporomandibular joint (TMJ)-associated inflammation contributes to the pain reported by patients with temporomandibular disorders (TMD). It is common for patients diagnosed with TMD to report pain in the masticatory muscles and temporomandibular joints, headache, and jaw movement disturbances. Although TMD can have different origins, including trauma and malocclusion disorder, anxiety/depression substantially impacts the development and maintenance of TMD. In general, rodent studies on orofacial pain mechanisms involve the use of tests originally developed for other body regions, which were adapted to the orofacial area. To overcome limitations and expand knowledge in orofacial pain, our group validated and characterized an operant assessment paradigm in rats with both hot and cold stimuli as well mechanical stimuli. Nevertheless, persistent inflammation of the TMJ has not been evaluated with this operant orofacial pain assessment device (OPAD). Methods We characterized the thermal orofacial sensitivity for cold, neutral, and hot stimuli during the development of TMD using the OPAD behavior test. In addition, we evaluated the role of transient receptor potential vanilloid 1 (TRPV1) expressing nociceptors in rats with persistent TMJ inflammation. The experiments were performed in male and female rats with TMJ inflammation induced by carrageenan (CARR). Additionally, resiniferatoxin (RTX) was administered into the TMJs prior CARR to lesion TRPV1-expressing neurons to evaluate the role of TRPV1-expressing neurons. Results We evidenced an increase in the number of facial contacts and changes in the number of reward licks per stimulus on neutral (37°C) and cold (21°C) temperatures. However, at the hot temperature (42°C), the inflammation did not induce changes in the OPAD test. The prior administration of RTX in the TMJ prevented the allodynia and thermal hyperalgesia induced by CARR. Conclusion We showed that TRPV-expressing neurons are involved in the sensitivity to carrageenan-induced pain in male and female rats evaluated in the OPAD.
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Affiliation(s)
- Christie R A Leite-Panissi
- Department of Psychology, School of Philosophy, Science and Literature of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Bruna B De Paula
- Department of Oral and Maxillofacial Surgery, University of Florida, Gainesville, FL, USA
| | - John K Neubert
- Department of Orthodontics, University of Florida, Gainesville, FL, USA
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida, Gainesville, FL, USA
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5
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Miller AL, Leach MC. Determining the preferred liquid reward in adult C57BL/6 mice. Lab Anim 2023; 57:332-335. [PMID: 36474418 PMCID: PMC10288164 DOI: 10.1177/00236772221138628] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/02/2022] [Indexed: 09/16/2023]
Abstract
Using food rewards to motivate mice is commonplace in behavioural research. Using a reward which is highly desirable is of benefit, as it can reduce the need to food restrict animals and can encourage higher levels of consumption, allowing for changes in levels of consumption following an intervention to be easily determined. Here, we aimed to determine the preferred milk reward for adult male C57Bl/6 mice. Thirty male C57Bl/6 mice were provided with soya milk, chocolate milk, almond milk or water for a four-hour period in a cross-over design. When planning studies that involve the use of a palatable liquid reward, soya milk is the preferred option for adult male C57BL/6 mice. Providing a liquid reward of high value will give increased levels of consumption, with little or no food restriction required.
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Affiliation(s)
- Amy L. Miller
- School of Health and Life Sciences, Teesside University, UK
| | - Matthew C Leach
- School of Natural and Environmental Sciences, Newcastle University, UK
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6
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Sadighparvar S, Al-Hamed FS, Sharif-Naeini R, Meloto CB. Preclinical orofacial pain assays and measures and chronic primary orofacial pain research: where we are and where we need to go. FRONTIERS IN PAIN RESEARCH 2023; 4:1150749. [PMID: 37293433 PMCID: PMC10244561 DOI: 10.3389/fpain.2023.1150749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/11/2023] [Indexed: 06/10/2023] Open
Abstract
Chronic primary orofacial pain (OFP) conditions such as painful temporomandibular disorders (pTMDs; i.e., myofascial pain and arthralgia), idiopathic trigeminal neuralgia (TN), and burning mouth syndrome (BMS) are seemingly idiopathic, but evidence support complex and multifactorial etiology and pathophysiology. Important fragments of this complex array of factors have been identified over the years largely with the help of preclinical studies. However, findings have yet to translate into better pain care for chronic OFP patients. The need to develop preclinical assays that better simulate the etiology, pathophysiology, and clinical symptoms of OFP patients and to assess OFP measures consistent with their clinical symptoms is a challenge that needs to be overcome to support this translation process. In this review, we describe rodent assays and OFP pain measures that can be used in support of chronic primary OFP research, in specific pTMDs, TN, and BMS. We discuss their suitability and limitations considering the current knowledge of the etiology and pathophysiology of these conditions and suggest possible future directions. Our goal is to foster the development of innovative animal models with greater translatability and potential to lead to better care for patients living with chronic primary OFP.
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Affiliation(s)
- Shirin Sadighparvar
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | | | - Reza Sharif-Naeini
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Department of Physiology and Cell Information Systems, McGill University, Montreal, QC, Canada
| | - Carolina Beraldo Meloto
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
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7
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Liu S, Crawford J, Tao F. Assessing Orofacial Pain Behaviors in Animal Models: A Review. Brain Sci 2023; 13:390. [PMID: 36979200 PMCID: PMC10046781 DOI: 10.3390/brainsci13030390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 08/25/2022] [Accepted: 02/22/2023] [Indexed: 02/26/2023] Open
Abstract
Orofacial pain refers to pain occurring in the head and face, which is highly prevalent and represents a challenge to clinicians, but its underlying mechanisms are not fully understood, and more studies using animal models are urgently needed. Currently, there are different assessment methods for analyzing orofacial pain behaviors in animal models. In order to minimize the number of animals used and maximize animal welfare, selecting appropriate assessment methods can avoid repeated testing and improve the reliability and accuracy of research data. Here, we summarize different methods for assessing spontaneous pain, evoked pain, and relevant accompanying dysfunction, and discuss their advantages and disadvantages. While the behaviors of orofacial pain in rodents are not exactly equivalent to the symptoms displayed in patients with orofacial pain, animal models and pain behavioral assessments have advanced our understanding of the pathogenesis of such pain.
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Affiliation(s)
| | | | - Feng Tao
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, TX 75246, USA
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8
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Tanaka M, Zhang Y. Preclinical Studies of Posttraumatic Headache and the Potential Therapeutics. Cells 2022; 12:cells12010155. [PMID: 36611947 PMCID: PMC9818317 DOI: 10.3390/cells12010155] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/13/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Posttraumatic headache (PTH) attributed to traumatic brain injury (TBI) is a secondary headache developed within 7 days after head injury, and in a substantial number of patients PTH becomes chronic and lasts for more than 3 months. Current medications are almost entirely relied on the treatment of primary headache such as migraine, due to its migraine-like phenotype and the limited understanding on the PTH pathogenic mechanisms. To this end, increasing preclinical studies have been conducted in the last decade. We focus in this review on the trigeminovascular system from the animal studies since it provides the primary nociceptive sensory afferents innervating the head and face region, and the pathological changes in the trigeminal pathway are thought to play a key role in the development of PTH. In addition to the pathologies, PTH-like behaviors induced by TBI and further exacerbated by nitroglycerin, a general headache inducer through vasodilation are reviewed. We will overview the current pharmacotherapies including calcitonin gene-related peptide (CGRP) monoclonal antibody and sumatriptan in the PTH animal models. Given that modulation of the endocannabinoid (eCB) system has been well-documented in the treatment of migraine and TBI, the therapeutic potential of eCB in PTH will also be discussed.
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9
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Patel S, Mittal R, Sarantopoulos KD, Galor A. Neuropathic ocular surface pain: Emerging drug targets and therapeutic implications. Expert Opin Ther Targets 2022; 26:681-695. [PMID: 36069761 PMCID: PMC9613591 DOI: 10.1080/14728222.2022.2122438] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 09/05/2022] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Dysfunction at various levels of the somatosensory system can lead to ocular surface pain with a neuropathic component. Compared to nociceptive pain (due to noxious stimuli at the ocular surface), neuropathic pain tends to be chronic and refractory to therapies, making it an important source of morbidity in the population. An understanding of the options available for neuropathic ocular surface pain, including new and emerging therapies, is thus an important topic. AREAS COVERED This review will examine studies focusing on ocular surface pain, emphasizing those examining patients with a neuropathic component. Attention will be placed toward recent (after 2017) studies that have examined new and emerging therapies for neuropathic ocular surface pain. EXPERT OPINION Several therapies have been studied thus far, and continued research is needed to identify which individuals would benefit from specific therapies. Gaps in our understanding exist, especially with availability of in-clinic diagnostics for neuropathic pain. A focus on improving diagnostic capabilities and researching gene-modulating therapies could help us to provide more specific mechanism-based therapies for patients. In the meantime, continuing to uncover new modalities and examining which are likely to work depending on pain phenotype remains an important short-term goal.
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Affiliation(s)
- Sneh Patel
- University of Miami Miller School of Medicine, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Rhiya Mittal
- University of Miami Miller School of Medicine, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Konstantinos D. Sarantopoulos
- Department of Anesthesiology, Perioperative Medicine, and Pain Management, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Anat Galor
- University of Miami Miller School of Medicine, Miami, FL, USA
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Surgical services, Miami Veterans Affairs Medical Center, Miami, FL, USA
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10
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Abdus-Saboor I, Luo W. Measuring Mouse Somatosensory Reflexive Behaviors with High-speed Videography, Statistical Modeling, and Machine Learning. NEUROMETHODS 2022; 178:441-456. [PMID: 35783537 PMCID: PMC9249079 DOI: 10.1007/978-1-0716-2039-7_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Objectively measuring and interpreting an animal's sensory experience remains a challenging task. This is particularly true when using preclinical rodent models to study pain mechanisms and screen for potential new pain treatment reagents. How to determine their pain states in a precise and unbiased manner is a hurdle that the field will need to overcome. Here, we describe our efforts to measure mouse somatosensory reflexive behaviors with greatly improved precision by high-speed video imaging. We describe how coupling sub-second ethograms of reflexive behaviors with a statistical reduction method and supervised machine learning can be used to create a more objective quantitative mouse "pain scale." Our goal is to provide the readers with a protocol of how to integrate some of the new tools described here with currently used mechanical somatosensory assays, while discussing the advantages and limitations of this new approach.
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Affiliation(s)
- Ishmail Abdus-Saboor
- Department of Biology, University of Pennsylvania, 3740 Hamilton Walk, Philadelphia, PA, 19104, USA
| | - Wenqin Luo
- Department of Neuroscience, University of Pennsylvania, 3610 Hamilton Walk, Philadelphia, PA, 19104, USA
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11
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Caudle RM, Neubert JK. Effects of Oxaliplatin on Facial Sensitivity to Cool Temperatures and TRPM8 Expressing Trigeminal Ganglion Neurons in Mice. FRONTIERS IN PAIN RESEARCH 2022; 3:868547. [PMID: 35634452 PMCID: PMC9130462 DOI: 10.3389/fpain.2022.868547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 04/18/2022] [Indexed: 12/04/2022] Open
Abstract
The chemotherapeutic agent oxaliplatin is commonly used to treat colorectal cancer. Although effective as a chemotherapeutic, it frequently produces painful peripheral neuropathies. These neuropathies can be divided into an acute sensitivity to cool temperatures in the mouth and face, and chronic neuropathic pain in the limbs and possible numbness. The chronic neuropathy also includes sensitivity to cool temperatures. Neurons that detect cool temperatures are reported to utilize Transient Receptor Potential Cation Channel, Subfamily M, Member 8 (TRPM8). Therefore, we investigated the effects of oxaliplatin on facial nociception to cool temperatures (18°C) in mice and on TRPM8 expressing trigeminal ganglion (TRG) neurons. Paclitaxel, a chemotherapeutic that is used to treat breast cancer, was included for comparison because it produces neuropathies, but acute cool temperature sensitivity in the oral cavity or face is not typically reported. Behavioral testing of facial sensitivity to 18°C indicated no hypersensitivity either acutely or chronically following either chemotherapeutic agent. However, whole cell voltage clamp experiments in TRPM8 expressing TRG neurons indicated that both oxaliplatin and paclitaxel increased Hyperpolarization-Activated Cyclic Nucleotide-Gated channel (HCN), voltage gated sodium channel (Nav), and menthol evoked TRPM8 currents. Voltage gated potassium channel (Kv) currents were not altered. Histological examination of TRPM8 fibers in the skin of the whisker pads demonstrated that the TRPM8 expressing axons and possible Merkel cell-neurite complexes were damaged by oxaliplatin. These findings indicate that oxaliplatin induces a rapid degeneration of TRG neuron axons that express TRPM8, which prevents evoked activation of the sensitized neurons and likely leads to reduced sensitivity to touch and cool temperatures. The changes in HCN, Nav, and TRPM8 currents suggest that spontaneous firing of action potentials may be increased in the deafferented neurons within the ganglion, possibly producing spontaneously induced cooling or nociceptive sensations.
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Affiliation(s)
- Robert M. Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida, Gainesville, FL, United States
| | - John K. Neubert
- Department of Orthodontics, University of Florida, Gainesville, FL, United States
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12
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Sadler KE, Mogil JS, Stucky CL. Innovations and advances in modelling and measuring pain in animals. Nat Rev Neurosci 2022; 23:70-85. [PMID: 34837072 PMCID: PMC9098196 DOI: 10.1038/s41583-021-00536-7] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2021] [Indexed: 12/12/2022]
Abstract
Best practices in preclinical algesiometry (pain behaviour testing) have shifted over the past decade as a result of technological advancements, the continued dearth of translational progress and the emphasis that funding institutions and journals have placed on rigour and reproducibility. Here we describe the changing trends in research methods by analysing the methods reported in preclinical pain publications from the past 40 years, with a focus on the last 5 years. We also discuss how the status quo may be hampering translational success. This discussion is centred on four fundamental decisions that apply to every pain behaviour experiment: choice of subject (model organism), choice of assay (pain-inducing injury), laboratory environment and choice of outcome measures. Finally, we discuss how human tissues, which are increasingly accessible, can be used to validate the translatability of targets and mechanisms identified in animal pain models.
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Affiliation(s)
- Katelyn E Sadler
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jeffrey S Mogil
- Department of Psychology, McGill University, Montreal, QC, Canada
- Department of Anesthesia, McGill University, Montreal, QC, Canada
| | - Cheryl L Stucky
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.
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13
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Salcido CA, Argenbright CM, Aguirre T, Trujillo AD, Fuchs PN. The Use of an FR1 Schedule Operant Approach-Avoidance Paradigm to Measure the Aversiveness of Neuropathic and Inflammatory Pain. FRONTIERS IN PAIN RESEARCH 2022; 2:793958. [PMID: 35295429 PMCID: PMC8915719 DOI: 10.3389/fpain.2021.793958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Pain is a subjective, private, yet universal phenomenon that depends on a unique combination of sensory, affective, and evaluative characteristics. Although preclinical models have been used to understand much of pain physiology, the inability to communicate with animals limits affective and evaluative feedback and has constrained traditional behavioral methods to adequately represent and study the multidimensional pain experience. Therefore, this study sought to characterize the affective component of pain within a novel operant approach-avoidance paradigm (AAP) to determine which type of pain (inflammatory and neuropathic) may be more aversive. To reveal the possible differences in pain aversiveness within the AAP paradigm, animals received bilateral inflammatory and neuropathic pain conditions and were given the choice to a) forgo appetitive reward by not receiving noxious stimulus of either inflammatory or neuropathic conditions or b) receive noxious stimulus in exchange for an appetitive reward. Although all pain conditions produced significant hypersensitivity, the AAP results revealed there was no preference in the stimulation of a specific paw in the bilateral pain conditions. The finding suggests that despite unique clinical pain characteristics for inflammatory and neuropathic conditions, the lack of observable differences in the pain conditions may not necessarily equate to the overall similarity in aversiveness, but rather that the fixed ratio (FR1) paradigm presentation allowed appetitive reward to be more salient, highlighting the complexities of competing motivational drives of pain and hunger when satiating hunger is always guaranteed. Thus, future studies should seek to further tease apart this relationship with a different schedule and food-controlled methodologies. The development of such preclinical approaches can thoroughly investigate the intricacy of competing drives and likely reveal important information regarding the complexity of pain, enhancing our understanding of pain perception in individuals suffering from comorbid pain states.
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Affiliation(s)
- Celina A. Salcido
- University of the Incarnate Word School of Osteopathic Medicine, San Antonio, TX, United States
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
| | - Cassie M. Argenbright
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
| | - Tiffany Aguirre
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
| | - Alex D. Trujillo
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
| | - Perry N. Fuchs
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
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14
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Okamoto K, Hasegawa M, Piriyaprasath K, Kakihara Y, Saeki M, Yamamura K. Preclinical models of deep craniofacial nociception and temporomandibular disorder pain. JAPANESE DENTAL SCIENCE REVIEW 2021; 57:231-241. [PMID: 34815817 PMCID: PMC8593658 DOI: 10.1016/j.jdsr.2021.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/15/2021] [Accepted: 10/19/2021] [Indexed: 01/06/2023] Open
Abstract
Chronic pain in temporomandibular disorder (TMD) is a common health problem. Cumulating evidence indicates that the etiology of TMD pain is complex with multifactorial experience that could hamper the developments of treatments. Preclinical research is a resource to understand the mechanism for TMD pain, whereas limitations are present as a disease-specific model. It is difficult to incorporate multiple risk factors associated with the etiology that could increase pain responses into a single animal. This article introduces several rodent models which are often employed in the preclinical studies and discusses their validities for TMD pain after the elucidations of the neural mechanisms based on the clinical reports. First, rodent models were classified into two groups with or without inflammation in the deep craniofacial tissues. Next, the characteristics of each model and the procedures to identify deep craniofacial pain were discussed. Emphasis was directed on the findings of the effects of chronic psychological stress, a major risk factor for chronic pain, on the deep craniofacial nociception. Preclinical models have provided clinically relevant information, which could contribute to better understand the basis for TMD pain, while efforts are still required to bridge the gap between animal and human studies.
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Affiliation(s)
- Keiichiro Okamoto
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Mana Hasegawa
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan.,Division of Dental Clinical Education, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Kajita Piriyaprasath
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Yoshito Kakihara
- Division of Dental Pharmacology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Makio Saeki
- Division of Dental Pharmacology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
| | - Kensuke Yamamura
- Division of Oral Physiology, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata City, 951-8514, Japan
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15
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Isaacson M, Hoon MA. An operant temperature sensory assay provides a means to assess thermal discrimination. Mol Pain 2021; 17:17448069211013633. [PMID: 33906493 PMCID: PMC8108075 DOI: 10.1177/17448069211013633] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Mouse behavioral assays have proven useful for the study of thermosensation, helping to identify receptors and circuits responsible for the transduction of thermal stimuli and information relay to the brain. However, these methods typically rely on observation of behavioral responses to various temperature stimuli to infer sensory ability and are often unable to disambiguate innocuous thermosensation from thermal nociception or to study thermosensory circuitry which do not produce easily detectable innate behavioral responses. Here we demonstrate a new testing apparatus capable of delivering small, rapid temperature change stimuli to the mouse’s skin, permitting the use of operant conditioning to train mice to recognize and report temperature change. Using this assay, mice that were trained to detect a large temperature change were found to generalize this learning to distinguish much smaller temperature changes across the entire range of innocuous temperatures tested. Mice with ablated TRPV1 and TRPM8 neuronal populations had reduced ability to discriminate temperature differences in the warm (>35°C) and cool (<30°C) ranges, respectively. Furthermore, mice that were trained to recognize temperature changes in only the cool, TRPM8-mediated temperature range did not generalize this learning in the warm, TRPV1-mediated range (and vice versa), suggesting that thermosensory information from the TRPM8- and TRPV1-neuronal populations are perceptually distinct.
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Affiliation(s)
- Matthew Isaacson
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, Bethesda, MD, USA.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Mark A Hoon
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, Bethesda, MD, USA
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16
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Paniagua N, Sánchez-Robles EM, Bagues A, Martín-Fontelles MI, Goicoechea C, Girón R. Behavior and electrophysiology studies of the peripheral neuropathy induced by individual and co-administration of paclitaxel and oxaliplatin in rat. Life Sci 2021; 277:119397. [PMID: 33794249 DOI: 10.1016/j.lfs.2021.119397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 11/26/2022]
Abstract
AIMS Antitumor agents, as taxanes and platinum compounds, induce peripheral neuropathies which can hamper their use for cancer treatment. The study of chemotherapy-induced neuropathies in humans is difficult because of ethical reasons, differences among administration protocols and intrinsic characteristics of patients. The aim of the present study is to compare the neuropathic signs induced by individual or combined administration of paclitaxel and oxaliplatin. MAIN METHODS Oxaliplatin and paclitaxel were administered individually and combined to induce peripheral neuropathy in rats, sensory neuropathic signs were assessed in the hind limbs and orofacial area. The in vitro skin-saphenous nerve preparation was used to record the axonal activity of Aδ sensory neurons. KEY FINDINGS Animals treated with the combination developed mechanical allodynia in the paws and muscular hyperalgesia in the orofacial area, which was similar to that in animals treated with monotherapy, the latter also developed cold allodynia in the paws. Aδ-fibers of the rats treated with the combination were hyperexcited and presented hypersensitivity to pressure stimulation of the innervated skin, also similar to that recorded in the fibers of the animals treated with monotherapy. SIGNIFICANCE Our work objectively demonstrates that the combination of a platinum compound with a taxane does not worsen the development of sensorial neuropathies in rats, which is an interesting data to take into account when the combination of antitumor drugs is necessary. Co-administration of antitumor drugs is more effective in cancer treatment without increasing the risk of the disabling neuropathic side effects.
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Affiliation(s)
- N Paniagua
- Área de Farmacología, Nutrición y Bromatología, Dpto. C.C. Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Unidad Asociada CSIC-IQM, High Performance Research Group in Experimental Pharmacology (PHARMAKOM), Alcorcón, Spain
| | - E M Sánchez-Robles
- Área de Farmacología, Nutrición y Bromatología, Dpto. C.C. Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Unidad Asociada CSIC-IQM, High Performance Research Group in Experimental Pharmacology (PHARMAKOM), Alcorcón, Spain
| | - A Bagues
- Área de Farmacología, Nutrición y Bromatología, Dpto. C.C. Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Unidad Asociada CSIC-IQM, High Performance Research Group in Experimental Pharmacology (PHARMAKOM), Alcorcón, Spain.
| | - M I Martín-Fontelles
- Área de Farmacología, Nutrición y Bromatología, Dpto. C.C. Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Unidad Asociada CSIC-IQM, High Performance Research Group in Experimental Pharmacology (PHARMAKOM), Alcorcón, Spain
| | - C Goicoechea
- Área de Farmacología, Nutrición y Bromatología, Dpto. C.C. Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Unidad Asociada CSIC-IQM, High Performance Research Group in Experimental Pharmacology (PHARMAKOM), Alcorcón, Spain
| | - R Girón
- Área de Farmacología, Nutrición y Bromatología, Dpto. C.C. Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Unidad Asociada CSIC-IQM, High Performance Research Group in Experimental Pharmacology (PHARMAKOM), Alcorcón, Spain
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17
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Abstract
Preclinical models that assess "pain" in rodents typically measure increases in behaviors produced by a "pain stimulus." A large literature exists showing that kappa opioid receptor (KOR) agonists can decrease these "pain-stimulated behaviors" following many different pain stimuli. Despite showing apparent antinociceptive properties in these preclinical models, KOR agonists failed as analgesics in clinical trials. Recent studies that assessed decreases in behavior due to a pain stimulus show that KOR agonists are not effective in restoring these "pain-depressed behaviors" to normal levels, which agrees with the lack of effectiveness for KOR agonists in clinical trials. One current explanation for the failure of previous KOR agonists in clinical trials is that those agonists activated beta-arrestin signaling and that KOR agonists with a greater bias for G protein signaling will be more successful. However, neither G protein-biased agonists nor beta-arrestin-biased agonists are very effective in assays of pain-depressed behavior, which suggests that novel biased agonists may still not be effective analgesics. This review provides a concise account of the effectiveness of KOR agonists in preclinical models of pain-stimulated and pain-depressed behaviors following the administration of different pain stimuli. Based on the previous results, it may be appropriate to include both behaviors when testing the analgesic potential of KOR agonists.
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Affiliation(s)
- Matthew F Lazenka
- Department of Biology and Chemistry, Liberty University, Lynchburg, VA, USA.
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18
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Caudle RM, Caudle SL, Flenor ND, Rohrs EL, Neubert JK. Pharmacological Characterization of Orofacial Nociception in Female Rats Following Nitroglycerin Administration. Front Pharmacol 2020; 11:527495. [PMID: 33343340 PMCID: PMC7744726 DOI: 10.3389/fphar.2020.527495] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 10/19/2020] [Indexed: 11/13/2022] Open
Abstract
Rodent models of human disease can be valuable for understanding the mechanisms of a disease and for identifying novel therapies. However, it is critical that these models be vetted prior to committing resources to developing novel therapeutics. Failure to confirm the model can lead to significant losses in time and resources. One model used for migraine headache is to administer nitroglycerin to rodents. Nitroglycerin is known to produce migraine-like pain in humans and is presumed to do the same in rodents. It is not known, however, if the mechanism for nitroglycerin headaches involves the same pathological processes as migraine. In the absence of known mechanisms, it becomes imperative that the model not only translates into successful clinical trials but also successfully reverse translates by demonstrating efficacy of current therapeutics. In this study female rats were given nitroglycerin and nociception was evaluated in OPADs. Estrous was not monitored. Based on the ED50 of nitroglycerin a dose of 10 mg/kg was used for experiments. Sumatriptan, caffeine, buprenorphine and morphine were administered to evaluate the reverse translatability of the model. We found that nitroglycerin did not produce mechanical allodynia in the face of the rats, which is reported to be a consequence of migraine in humans. Nitroglycerin reduced the animals’ participation in the assay. The reduced activity was verified using an assay to measure exploratory behavior. Furthermore, the effects of nitroglycerin were not reversed or prevented by agents that are effective acute therapies for migraine. Two interesting findings from this study, however, were that morphine and nitroglycerin interact to increase the rats’ tolerance of mechanical stimuli on their faces, and they work in concert to slow down the central motor pattern generator for licking on the reward bottle. These interactions suggest that nitroglycerin generated nitric oxide and mu opioid receptors interact with the same neuronal circuits in an additive manner. The interaction of nitroglycerin and morphine on sensory and motor circuits deserves additional examination. In conclusion, based on the results of this study the use of nitroglycerin at these doses in naïve female rats is not recommended as a model for migraine headaches.
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Affiliation(s)
- Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida, Gainesville, FL, United States
| | - Stephanie L Caudle
- Department of Orthodontics, University of Florida, Gainesville, FL, United States
| | - Natalie D Flenor
- Department of Orthodontics, University of Florida, Gainesville, FL, United States
| | - Eric L Rohrs
- Velocity Laboratories, LLC, Alachua, FL, United States
| | - John K Neubert
- Department of Orthodontics, University of Florida, Gainesville, FL, United States
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19
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Reker AN, Chen S, Etter K, Burger T, Caudill M, Davidson S. The Operant Plantar Thermal Assay: A Novel Device for Assessing Thermal Pain Tolerance in Mice. eNeuro 2020; 7:ENEURO.0210-19.2020. [PMID: 32071073 PMCID: PMC7078811 DOI: 10.1523/eneuro.0210-19.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 02/07/2023] Open
Abstract
Pain is a multidimensional experience of sensory-discriminative, cognitive, and affective processes; however, current basic research methods rely heavily on response to threshold stimuli, bypassing the supraspinal processing that ultimately gives rise to the pain experience. We developed the operant plantar thermal assay (OPTA), which utilizes a novel, conflict-based operant task requiring evaluation and active decision-making to obtain reward under thermally aversive conditions to quantify thermal pain tolerance. In baseline measures, male and female mice exhibited similar temperature preferences, however in the OPTA, female mice exhibited greater temperature-dependent tolerance, as defined by choice time spent in an adverse thermal condition to obtain reward. Increasing reward salience (4% vs 10% sucrose solution) led to increased thermal tolerance for males but not females. To determine whether neuropathic and inflammatory pain models alter thermal tolerance, animals with chronic constriction injury (CCI) or complete Freund's adjuvant (CFA), respectively, were tested in the OPTA. Surprisingly, neuropathic animals exhibited increased thermal tolerance, as shown by greater time spent in the reward zone in an adverse thermal condition, compared with sham animals. There was no effect of inflammation on thermal tolerance. Administration of clonidine in the CCI model led to increased thermal tolerance in both injured and sham animals. In contrast, the non-steroidal anti-inflammatory meloxicam was anti-hyperalgesic in the CFA model, but reduced thermal pain tolerance. These data support the feasibility of using the OPTA to assess thermal pain tolerance to gain new insights into complex pain behaviors and to investigate novel aspects of analgesic efficacy.
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Affiliation(s)
- Ashlie N Reker
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH 45267
| | - Sisi Chen
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH 45267
| | - Katherine Etter
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH 45267
| | - Taylor Burger
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH 45267
| | - Makayla Caudill
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH 45267
| | - Steve Davidson
- Department of Anesthesiology and Pain Research Center, University of Cincinnati, College of Medicine, Cincinnati, OH 45267
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20
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Developing Improved Translational Models of Pain: A Role for the Behavioral Scientist. Perspect Behav Sci 2020; 43:39-55. [PMID: 32440644 DOI: 10.1007/s40614-019-00239-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The effective management of pain is a longstanding public health concern. Although opioids have been frontline analgesics for decades, they also have well-known undesirable effects that limit their clinical utility, such as abuse liability and respiratory depression. The failure to develop better analgesics has, in some ways, contributed to the escalating opioid epidemic that has claimed tens of thousands of lives and has cost hundreds of billions of dollars in health-care expenses. A paradigm shift is needed in the pharmacotherapy of pain management that will require extensive efforts throughout biomedical science. The purpose of the present review is to highlight the critical role of the behavioral scientist to devise improved translational models of pain for drug development. Despite high heterogeneity of painful conditions that involve cortical-dependent pain processing, current models often feature an overreliance on simple reflex-based measures and an emphasis on the absence, rather than presence, of behavior as evidence of analgesic efficacy. Novel approaches should focus on the restoration of operant and other CNS-mediated behavior under painful conditions.
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21
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Khan J, Puchimada B, Kadouri D, Zusman T, Javed F, Eliav E. The anti-nociceptive effects of Porphyromonas gingivalis lipopolysaccharide. Arch Oral Biol 2019; 102:193-198. [PMID: 31071639 DOI: 10.1016/j.archoralbio.2019.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/15/2019] [Accepted: 04/19/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The objective of this study was to assess the effect of Porphyromonas gingivalis lipopolysaccharide (PG LPS) on acute pain-related behaviour induced in rats and to measure its impact on the levels of pro-inflammatory cytokines (IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines. DESIGN The Brennan model was used to induce acute pain like signs in rats' hind paw. Twenty-four hours following the surgery the rats were divided into 5 groups and the affected paws were injected with 0.2 m l of one of three commercialized forms PG LPS doses (high - 1 mg/ml, medium - 0.6 mg/m l and low - 0.2 mg/m l), diclofenac sodium (1 mg/kg) or saline. Tactile allodynia, mechanical hyperalgesia, body temperature and paw swelling were assessed at baseline, 24 h postoperatively and 2 h after the paw injection. The affected and contra-lateral paw tissue was assessed for the mentioned above cytokines levels employing enzyme-linked immunosorbent assay. RESULTS This study may suggest that PG LPS can reduce pain like behaviour via increased levels of anti-inflammatory cytokine IL-10 (5900 ± 748, p < 0.05). The high PG LPS dose and diclofenac reduced the tactile allodynia and mechanical hyperalgesia significantly (42.2 ± 4 and1.6 ± 0.3, p < 0.05). PG LPS high dose increase IL-10 levels while diclofenac reduces IL-1β levels significantly (5900 ± 748 and 1760 ± 271.2). The LPS administration had no effect on paw swelling and did not increase rat's body temperature. CONCLUSION The results demonstrated that PG LPS local application could possess anti- nociceptive properties, which at least in part is mediated by an increase in IL-10 levels.
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Affiliation(s)
- Junad Khan
- Orofacial Pain and Temporomandibular Joint Disorders, Eastman Institute for Oral Health, University of Rochester, 625 Elmwood Avenue, Rochester, NY, 14620, USA.
| | - Bollama Puchimada
- Department of Diagnostic Sciences, Rutgers School of Dental Medicine, NJ, USA
| | - Daniel Kadouri
- Oral Biology, Rutgers School of Dental Medicine, NJ, USA
| | - Tali Zusman
- Department of Diagnostic Sciences, Rutgers School of Dental Medicine, NJ, USA
| | - Fawad Javed
- Department of Periodontology, Stony Brook University, Stony Brook, NY, USA; Laboratory for Periodontal-, Implant-, Phototherapy (LA-PIP), School of Dental Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Eli Eliav
- Eastman Institute for Oral Health, University of Rochester, NY, USA
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22
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Abstract
All preclinical procedures for analgesic drug discovery involve two components: 1) a "pain stimulus" (the principal independent variable), which is delivered to an experimental subject with the intention of producing a pain state; and 2) a "pain behavior" (the principal dependent variable), which is measured as evidence of that pain state. Candidate analgesics are then evaluated for their effectiveness to reduce the pain behavior, and results are used to prioritize drugs for advancement to clinical testing. This review describes a taxonomy of preclinical procedures organized into an "antinociception matrix" by reference to their types of pain stimulus (noxious, inflammatory, neuropathic, disease related) and pain behavior (unconditioned, classically conditioned, operant conditioned). Particular emphasis is devoted to pain behaviors and the behavioral principals that govern their expression, pharmacological modulation, and preclinical-to-clinical translation. Strengths and weaknesses are compared and contrasted for procedures using each type of behavioral outcome measure, and the following four recommendations are offered to promote strategic use of these procedures for preclinical-to-clinical analgesic drug testing. First, attend to the degree of homology between preclinical and clinical outcome measures, and use preclinical procedures with behavioral outcome measures homologous to clinically relevant outcomes in humans. Second, use combinations of preclinical procedures with complementary strengths and weaknesses to optimize both sensitivity and selectivity of preclinical testing. Third, take advantage of failed clinical translation to identify drugs that can be back-translated preclinically as active negative controls. Finally, increase precision of procedure labels by indicating both the pain stimulus and the pain behavior in naming preclinical procedures.
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Affiliation(s)
- S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
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23
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IL-10 and CXCL2 in trigeminal ganglia in neuropathic pain. Neurosci Lett 2019; 703:132-138. [PMID: 30904573 DOI: 10.1016/j.neulet.2019.03.031] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 03/11/2019] [Accepted: 03/19/2019] [Indexed: 01/31/2023]
Abstract
Many trigeminal neuropathic pain patients suffer severe chronic pain. The neuropathic pain might be related with cross-excitation of the neighboring neurons and satellite glial cells (SGCs) in the sensory ganglia and increasing the pain signals from the peripheral tissue to the central nervous system. We induced trigeminal neuropathic pain by infraorbital nerve constriction injury (IONC) in Sprague-Dawley rats. We tested cytokine (CXCL2 and IL-10) levels in trigeminal ganglia (TGs) after trigeminal neuropathic pain induction, and the effect of direct injection of the anti-CXCL2 and recombinant IL-10 into TG. We found that IONC induced pain behavior. Additionally, IONC induced satellite glial cell activation in TG and cytokine levels of TGs were changed after IONC. CXCL2 levels increased on day 1 of neuropathic pain induction and decreased gradually, with IL-10 levels showing the opposite trend. Recombinant IL-10 or anti-CXCL2 injection into TG decreased pain behavior. Our results show that IL-10 or anti-CXCL2 are therapy options for neuropathic pain.
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Ling J, Erol F, Viatchenko-Karpinski V, Kanda H, Gu JG. Orofacial neuropathic pain induced by oxaliplatin: downregulation of KCNQ2 channels in V2 trigeminal ganglion neurons and treatment by the KCNQ2 channel potentiator retigabine. Mol Pain 2018; 13:1744806917724715. [PMID: 28741430 PMCID: PMC5549876 DOI: 10.1177/1744806917724715] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Neuropathic pain induced by chemotherapy drugs such as oxaliplatin is a dose-limiting side effect in cancer treatment. The mechanisms underlying chemotherapy-induced neuropathic pain are not fully understood. KCNQ2 channels are low-threshold voltage-gated K+ channels that play a role in controlling neuronal excitability. Downregulation of KCNQ2 channels has been proposed to be an underlying mechanism of sensory hypersensitivity that leads to neuropathic pain. However, it is currently unknown whether KCNQ channels may be downregulated by chemotherapy drugs in trigeminal ganglion neurons to contribute to the pathogenesis of chemotherapy-induced orofacial neuropathic pain. In the present study, mechanical sensitivity in orofacial regions is measured using the operant behavioral test in rats treated with oxaliplatin. Operant behaviors in these animals show the gradual development of orofacial neuropathic pain that manifests with orofacial mechanical allodynia. Immunostaining shows strong KCNQ2 immunoreactivity in small-sized V2 trigeminal ganglion neurons in controls, and the numbers of KCNQ2 immunoreactivity positive V2 trigeminal ganglion neurons are significantly reduced in oxaliplatin-treated animals. Immunostaining is also performed in brainstem and shows strong KCNQ2 immunoreactivity at the trigeminal afferent central terminals innervating the caudal spinal trigeminal nucleus (Vc) in controls, but the KCNQ2 immunoreactivity intensity is significantly reduced in oxaliplatin-treated animals. We further show with the operant behavioral test that oxaliplatin-induced orofacial mechanical allodynia can be alleviated by the KCNQ2 potentiator retigabine. Taken together, these findings suggest that KCNQ2 downregulation may be a cause of oxaliplatin-induced orofacial neuropathic pain and KCNQ2 potentiators may be useful for alleviating the neuropathic pain.
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Affiliation(s)
- Jennifer Ling
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ferhat Erol
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Hirosato Kanda
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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Zeng Y, Hu D, Yang W, Hayashinaka E, Wada Y, Watanabe Y, Zeng Q, Cui Y. A voxel-based analysis of neurobiological mechanisms in placebo analgesia in rats. Neuroimage 2018; 178:602-612. [DOI: 10.1016/j.neuroimage.2018.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/22/2018] [Accepted: 06/04/2018] [Indexed: 12/19/2022] Open
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26
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Bowden LN, Rohrs EL, Omoto K, Durham PL, Holliday LS, Morris AD, Allen KD, Caudle RM, Neubert JK. Effects of cocoa-enriched diet on orofacial pain in a murine model. Orthod Craniofac Res 2018. [PMID: 28643911 DOI: 10.1111/ocr.12149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES To investigate and discuss the effects of cocoa on orofacial pain. SETTING AND SAMPLE POPULATION The Department of Orthodontics at the University of Florida (UF). Male and female hairless rats (N=20/group) were tested. MATERIALS AND METHODS Rats were tested using the Orofacial Pain Assessment Device (OPAD) before and after changing their food from the standard chow to a cocoa-enriched or control-equivalent diet. RESULTS Male rats fed the cocoa diet had a significantly higher operant pain index when tested at 37°C as compared to control diet-fed animals. Female rats on the cocoa diet had a significantly higher pain index when tested at 18°C and 44°C, as compared to animals fed the control diet. Capsaicin-induced pain was inhibited, with cocoa-diet male rats having a significantly higher pain index than control-diet male rats and cocoa-diet female rats at both 37°C and 44°C. Cocoa-diet female rats had a significantly higher pain index at 44°C than control-diet females. Mechanical sensitivity was affected following capsaicin cream, with a significantly decreased tolerated bottle distance in both cocoa- and control-diet animals, but there was no difference between cocoa- and control-diet groups. CONCLUSION Using the OPAD operant system, we demonstrated that a diet rich in cocoa was effective in inhibiting neurogenic inflammatory pain in rats. This has implications for the use of novel alternative therapies such as diet modification for pain control.
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Affiliation(s)
- L N Bowden
- Department of Orthodontics, University of Florida, Gainesville, FL, USA
| | - E L Rohrs
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - K Omoto
- Department of Stomatognathic Function and Occlusal Reconstruction, Tokushima University, Tokushima, Japan
| | - P L Durham
- Department of Biology, Missouri State University, Springfield, MO, USA
| | - L S Holliday
- Department of Orthodontics, University of Florida, Gainesville, FL, USA
| | - A D Morris
- Department of Orthodontics, University of Florida, Gainesville, FL, USA
| | - K D Allen
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - R M Caudle
- Department of Oral & Maxillofacial Surgery, University of Florida, Gainesville, FL, USA
| | - J K Neubert
- Department of Orthodontics, University of Florida, Gainesville, FL, USA
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Salcido CA, Harris Bozer AL, McNabb CT, Fuchs PN. Assessing the aversive nature of pain with an operant approach/avoidance paradigm. Physiol Behav 2018; 189:59-63. [PMID: 29501556 DOI: 10.1016/j.physbeh.2018.02.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 02/21/2018] [Accepted: 02/28/2018] [Indexed: 12/18/2022]
Abstract
Preclinical pain assessments can be criticized for failing to adequately characterize the human clinical pain experience. Although recent assessments have improved upon this shortcoming, there are still significant limitations. One concern is that current procedures fail to examine underlying motivational drives related to pain. Therefore, we used a novel approach-avoidance paradigm that allowed a rat to either satisfy hunger or avoid noxious stimulation to reveal prioritizing of motivational drives. The operant paradigm utilized a single lever that the animal pressed for appetitive reward (approach). The lever press was associated with mechanical stimulation of an inflamed paw induced by subcutaneous injection of carrageenan (avoidance). The results revealed that carrageenan-injected animals had a significant suppression of lever pressing and, in addition, had a longer latency to approach and press a lever for appetitive reward. The pattern of operant behavioral responses indicates that the motivation to avoid pain superseded the motivation to alleviate hunger. Utilization of approach-avoidance paradigms, such as this one, can allow researchers to unravel the complexities of the pain experience with the goal of enhancing translation to clinical efficacy.
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Affiliation(s)
- Celina A Salcido
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Amber L Harris Bozer
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Christopher T McNabb
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Perry N Fuchs
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, USA; Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA.
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Abstract
Failure of analgesic drugs in clinical development is common. Along with the current "reproducibility crisis" in pain research, this has led some to question the use of animal models. Experimental models tend to comprise genetically homogeneous groups of young, male rodents in restricted and unvarying environments, and pain-producing assays that may not closely mimic the natural condition of interest. In addition, typical experimental outcome measures using thresholds or latencies for withdrawal may not adequately reflect clinical pain phenomena pertinent to human patients. It has been suggested that naturally occurring disease in veterinary patients may provide more valid models for the study of painful disease. Many painful conditions in animals resemble those in people. Like humans, veterinary patients are genetically diverse, often live to old age, and enjoy a complex environment, often the same as their owners. There is increasing interest in the development and validation of outcome measures for detecting pain in veterinary patients; these include objective (eg, locomotor activity monitoring, kinetic evaluation, quantitative sensory testing, and bioimaging) and subjective (eg, pain scales and quality of life scales) measures. Veterinary subject diversity, pathophysiological similarities to humans, and diverse outcome measures could yield better generalizability of findings and improved translation potential, potentially benefiting both humans and animals. The Comparative Oncology Trial Consortium in dogs has pawed the way for translational research, surmounting the challenges inherent in veterinary clinical trials. This review describes numerous conditions similarly applicable to pain research, with potential mutual benefits for human and veterinary clinicians, and their respective patients.
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Rohrs EL, Neubert JK, Caudle RM, Allen KD. Behavioral characteristics of capsaicin mediated cutaneous, myogenic, and arthrogenic orofacial nociception in rats. Arch Oral Biol 2018; 92:18-24. [PMID: 29738922 DOI: 10.1016/j.archoralbio.2018.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 04/06/2018] [Accepted: 04/26/2018] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To assess changes in orofacial tactile sensitivity and gnawing related to capsaicin-mediated cutaneous, myogenic, and arthrogenic nociception in the rat. DESIGN After recovery from anesthesia, orofacial tactile sensitivity and gnawing were assessed using operant testing methods following capsaicin application. Twenty female CD-Hairless rats were tested with bilateral capsaicin cream application to the cheek or with isoflurane anesthesia alone. Following several weeks of recovery, animals (n = 20) received either 10 μL unilateral masseter injections of vehicle, or phosphate buffered saline (PBS) to assess injection sensitization. After several weeks, masseter capsaicin (1.0%) injections (10 μL) were assessed compared to vehicle and PBS (n = 13). Weeks later capsaicin TMJ injections were evaluated. Animals (n = 11) received either 10 μL unilateral TMJ injections of capsaicin solution (1%) or vehicle. RESULTS Capsaicin cream to the skin significantly altered gnawing activity (increased puncture time by 248 s (p = 0.0002)) and tactile sensitivity (decreased tolerated bottle distance by 0.980 cm compared to isoflurane only (p = 0.0001)). Similarly, capsaicin masseter injection increased puncture time (339.6 s, p = 0.07) and decreased tolerated bottle distance (1.04 cm, p = 0.005) compared to vehicle. However, intra-articular capsaicin in the TMJ only modified gnawing (increased puncture time by 133 s), with no changes found in tactile sensitivity compared to vehicle. CONCLUSION Application of capsaicin to the skin and masseter had similar behavioral effects; however, intra-articular injections to the TMJ only affected gnawing. These data indicate the behavioral changes in rodent models of myogenic and cutaneous pain may be markedly different than models of arthrogenic pain originating from the TMJ.
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Affiliation(s)
- Eric L Rohrs
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Gainesville, FL, 32611, United States.
| | - John K Neubert
- Department of Orthodontics, University of Florida, 1395 Center Drive, Gainesville, FL, 32611, United States; Pain Research and Intervention Center of Excellence, University of Florida, 1329 SW 16th Street, Gainesville, FL, 32608, United States.
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida, 1395 Center Drive, D7-6, Gainesville, FL, 32610, United States; Pain Research and Intervention Center of Excellence, University of Florida, 1329 SW 16th Street, Gainesville, FL, 32608, United States.
| | - Kyle D Allen
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Gainesville, FL, 32611, United States; Pain Research and Intervention Center of Excellence, University of Florida, 1329 SW 16th Street, Gainesville, FL, 32608, United States; Institute for Cell Engineering and Regenerative Medicine, University of Florida, 300 Weil Hall, 1949 Stadium Road, Gainesville, FL, 32611, United States; Nanoscience Institute for Medical and Engineering Technology, University of Florida, 1041 Center Dr, Gainesville, FL, 32611, United States.
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Sapio MR, Neubert JK, LaPaglia DM, Maric D, Keller JM, Raithel SJ, Rohrs EL, Anderson EM, Butman JA, Caudle RM, Brown DC, Heiss JD, Mannes AJ, Iadarola MJ. Pain control through selective chemo-axotomy of centrally projecting TRPV1+ sensory neurons. J Clin Invest 2018; 128:1657-1670. [PMID: 29408808 DOI: 10.1172/jci94331] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 02/01/2018] [Indexed: 11/17/2022] Open
Abstract
Agonists of the vanilloid receptor transient vanilloid potential 1 (TRPV1) are emerging as highly efficacious nonopioid analgesics in preclinical studies. These drugs selectively lesion TRPV1+ primary sensory afferents, which are responsible for the transmission of many noxious stimulus modalities. Resiniferatoxin (RTX) is a very potent and selective TRPV1 agonist and is a promising candidate for treating many types of pain. Recent work establishing intrathecal application of RTX for the treatment of pain resulting from advanced cancer has demonstrated profound analgesia in client-owned dogs with osteosarcoma. The present study uses transcriptomics and histochemistry to examine the molecular mechanism of RTX action in rats, in clinical canine subjects, and in 1 human subject with advanced cancer treated for pain using intrathecal RTX. In all 3 species, we observe a strong analgesic action, yet this was accompanied by limited transcriptional alterations at the level of the dorsal root ganglion. Functional and neuroanatomical studies demonstrated that intrathecal RTX largely spares susceptible neuronal perikarya, which remain active peripherally but unable to transmit signals to the spinal cord. The results demonstrate that central chemo-axotomy of the TRPV1+ afferents underlies RTX analgesia and refine the neurobiology underlying effective clinical use of TRPV1 agonists for pain control.
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Affiliation(s)
- Matthew R Sapio
- Clinical Center, Department of Perioperative Medicine, NIH, Bethesda, Maryland, USA
| | - John K Neubert
- Department of Orthodontics, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Danielle M LaPaglia
- Clinical Center, Department of Perioperative Medicine, NIH, Bethesda, Maryland, USA
| | - Dragan Maric
- Flow Cytometry Core Facility, NIH, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
| | - Jason M Keller
- Clinical Center, Department of Perioperative Medicine, NIH, Bethesda, Maryland, USA
| | - Stephen J Raithel
- Clinical Center, Department of Perioperative Medicine, NIH, Bethesda, Maryland, USA
| | - Eric L Rohrs
- Department of Orthodontics, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Ethan M Anderson
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - John A Butman
- Clinical Center, Radiology and Imaging Services, NIH, Bethesda, Maryland, USA
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida, USA
| | - Dorothy C Brown
- Veterinary Clinical Investigations Center, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - John D Heiss
- Surgical Neurology Branch, NIH, National Institute of Neurological Disorders and Stroke, Bethesda, Maryland, USA
| | - Andrew J Mannes
- Clinical Center, Department of Perioperative Medicine, NIH, Bethesda, Maryland, USA
| | - Michael J Iadarola
- Clinical Center, Department of Perioperative Medicine, NIH, Bethesda, Maryland, USA
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Placebo Analgesia in Rodents: Current and Future Research. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 138:1-15. [PMID: 29681320 DOI: 10.1016/bs.irn.2018.02.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The investigation of placebo effects in animal pain models has received less attention than human research. This may be related to a number of difficulties, including the fact that animals lack the ability to use language and establish expectancies verbally, that animals cannot report and rate the extent to which they experience pain, and the inadequacy of current models of pain. Here, we describe the relatively small number of studies that have been published, communicating the opportunities and excitement of this research. We critically discuss pitfalls and limitations with the hope that this will advance future animal placebo-related research.
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Fischer BD, Adeyemo A, O'Leary ME, Bottaro A. Animal models of rheumatoid pain: experimental systems and insights. Arthritis Res Ther 2017; 19:146. [PMID: 28666464 PMCID: PMC5493070 DOI: 10.1186/s13075-017-1361-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Severe chronic pain is one of the hallmarks and most debilitating manifestations of inflammatory arthritis. It represents a significant problem in the clinical management of patients with common chronic inflammatory joint conditions such as rheumatoid arthritis, psoriatic arthritis and spondyloarthropathies. The functional links between peripheral inflammatory signals and the establishment of the neuroadaptive mechanisms acting in nociceptors and in the central nervous system in the establishment of chronic and neuropathic pain are still poorly understood, representing an area of intense study and translational priority. Several well-established inducible and spontaneous animal models are available to study the onset, progression and chronicization of inflammatory joint disease, and have been instrumental in elucidating its immunopathogenesis. However, quantitative assessment of pain in animal models is technically and conceptually challenging, and it is only in recent years that inflammatory arthritis models have begun to be utilized systematically in experimental pain studies using behavioral and neurophysiological approaches to characterize acute and chronic pain stages. This article aims primarily to provide clinical and experimental rheumatologists with an overview of current animal models of arthritis pain, and to summarize emerging findings, challenges and unanswered questions in the field.
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Affiliation(s)
- Bradford D Fischer
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, 401 S. Broadway, Camden, NJ, 08103, USA
| | - Adeshina Adeyemo
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, 401 S. Broadway, Camden, NJ, 08103, USA
| | - Michael E O'Leary
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, 401 S. Broadway, Camden, NJ, 08103, USA
| | - Andrea Bottaro
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, 401 S. Broadway, Camden, NJ, 08103, USA.
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Blivis D, Haspel G, Mannes PZ, O'Donovan MJ, Iadarola MJ. Identification of a novel spinal nociceptive-motor gate control for Aδ pain stimuli in rats. eLife 2017; 6. [PMID: 28537555 PMCID: PMC5470870 DOI: 10.7554/elife.23584] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/22/2017] [Indexed: 11/23/2022] Open
Abstract
Physiological responses to nociceptive stimuli are initiated within tens of milliseconds, but the corresponding sub-second behavioral responses have not been adequately explored in awake, unrestrained animals. A detailed understanding of these responses is crucial for progress in pain neurobiology. Here, high-speed videography during nociceptive Aδ fiber stimulation demonstrated engagement of a multi-segmental motor program coincident with, or even preceding, withdrawal of the stimulated paw. The motor program included early head orientation and adjustments of the torso and un-stimulated paws. Moreover, we observed a remarkably potent gating mechanism when the animal was standing on its hindlimbs and which was partially dependent on the endogenous opioid system. These data reveal a profound, immediate and precise integration of nociceptive inputs with ongoing motor activities leading to the initiation of complex, yet behaviorally appropriate, response patterns and the mobilization of a new type of analgesic mechanism within this early temporal nociceptive window. DOI:http://dx.doi.org/10.7554/eLife.23584.001 A bee sting or a pinprick are examples of painful experiences that trigger an immediate response in humans and other animals. Scientists have begun mapping how different parts of the nervous system control how the body reacts to pain. But there are still many questions about what happens in the very first moments after pain. For example, does the response depend on what the body is doing when the painful event occurs? Examining how animals move in response to pain may help answer these questions and possibly point to new strategies for treating pain. Now, Blivis et al. show that the nervous system orchestrates a sequence of movements in the whole body in the first 500 milliseconds after a painful event. In the experiments, a high-speed video camera recorded what happened when rats experience a pinprick or brief burst from a hot laser on one paw. When a rat is on all four paws, it first moves it head and then picks up its foot after one of these painful experiences. In fact, the position of the rat’s entire body moves to enable the head to turn towards the source of the pain. This may help the rat assess the threat and decide what to do about it. When a rat is standing on two hind legs, however, the animal’s pain reaction is delayed until the animal attains a more stable footing. The rat puts its front paws down, before moving its foot from the source of the pain. Future studies are needed to identify which parts of the brain and spinal cord are active during these early, rapid movements and if something similar happens in humans. If a similar process occurs in humans, scientists might be able to develop new pain medications that take advantage of the system that temporarily suppresses the body’s immediate reaction to pain. These medications could, in future, be used to treat the heightened sensitivity to pain that can occur after an injury, or the intense “breakthrough” pain experienced by cancer patients that cannot be controlled by their usual pain medication. DOI:http://dx.doi.org/10.7554/eLife.23584.002
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Affiliation(s)
- Dvir Blivis
- Developmental Neurobiology Section, Laboratory of Neural Control, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Gal Haspel
- Developmental Neurobiology Section, Laboratory of Neural Control, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States.,Federated Department of Biological Sciences, New Jersey Institute of Technology, and Rutgers, Newark, United States
| | - Philip Z Mannes
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Disorders, National Institutes of Health, Bethesda, United States
| | - Michael J O'Donovan
- Developmental Neurobiology Section, Laboratory of Neural Control, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Michael J Iadarola
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, United States
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Sex differences in mouse Transient Receptor Potential Cation Channel, Subfamily M, Member 8 expressing trigeminal ganglion neurons. PLoS One 2017; 12:e0176753. [PMID: 28472061 PMCID: PMC5417611 DOI: 10.1371/journal.pone.0176753] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 04/17/2017] [Indexed: 01/04/2023] Open
Abstract
The detection of cool temperatures is thought to be mediated by primary afferent neurons that express the cool temperature sensing protein Transient Receptor Potential Cation Channel, Subfamily M, Member 8 (TRPM8). Using mice, this study tested the hypothesis that sex differences in sensitivity to cool temperatures were mediated by differences in neurons that express TRPM8. Ion currents from TRPM8 expressing trigeminal ganglion (TRG) neurons in females demonstrated larger hyperpolarization-activated cyclic nucleotide-gated currents (Ih) than male neurons at both 30° and 18°C. Additionally, female neurons' voltage gated potassium currents (Ik) were suppressed by cooling, whereas male Ik was not significantly affected. At the holding potential tested (-60mV) TRPM8 currents were not visibly activated in either sex by cooling. Modeling the effect of Ih and Ik on membrane potentials demonstrated that at 30° the membrane potential in both sexes is unstable. At 18°, female TRPM8 TRG neurons develop a large oscillating pattern in their membrane potential, whereas male neurons become highly stable. These findings suggest that the differences in Ih and Ik in the TRPM8 TRG neurons of male and female mice likely leads to greater sensitivity of female mice to the cool temperature. This hypothesis was confirmed in an operant reward/conflict assay. Female mice contacted an 18°C surface for approximately half the time that males contacted the cool surface. At 33° and 10°C male and female mice contacted the stimulus for similar amounts of time. These data suggest that sex differences in the functioning of Ih and Ik in TRPM8 expressing primary afferent neurons leads to differences in cool temperature sensitivity.
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Moye LS, Pradhan AA. From blast to bench: A translational mini-review of posttraumatic headache. J Neurosci Res 2017; 95:1347-1354. [PMID: 28151589 DOI: 10.1002/jnr.24001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 11/07/2016] [Accepted: 11/28/2016] [Indexed: 12/25/2022]
Abstract
Current events within the military and professional sports have resulted in an increased recognition of the long-term and debilitating consequences of traumatic brain injury. Mild traumatic brain injury accounts for the majority of head injuries, and posttraumatic headache is the most common adverse effect. It is estimated that between 30% to 90% of traumatic brain injuries result in posttraumatic headache, and for a significant number of people this headache disorder can continue for up to and over a year post injury. Often, the most severe and chronic posttraumatic headache has a migraine-like phenotype and is difficult to resolve. In this review we discuss the preclinical findings from animal models of posttraumatic headache. We also describe potential mechanisms by which traumatic brain injury leads to chronic posttraumatic headache, including neuroinflammatory mediators and migraine-associated neuropeptides. There are surprisingly few preclinical studies that have investigated overlapping mechanisms between posttraumatic headache and migraine, especially considering the prevalence and debilitating nature of posttraumatic headache. Given this context, posttraumatic headache is a field with many emerging opportunities for growth. The frequency of posttraumatic headache in the general and military population is rising, and further preclinical research is required to understand, ameliorate, and treat this disabling disorder. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Laura S Moye
- Department of Psychiatry, University of Illinois at Chicago
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36
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Almeida RT, Romero TRL, Romero MGMEC, de Souza GG, Perez ADC, Duarte IDG. Endocannabinoid mechanism for orofacial antinociception induced by electroacupuncture in acupoint St36 in rats. Pharmacol Rep 2016; 68:1095-1101. [DOI: 10.1016/j.pharep.2016.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 06/28/2016] [Accepted: 07/20/2016] [Indexed: 10/21/2022]
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Ison SH, Clutton RE, Di Giminiani P, Rutherford KMD. A Review of Pain Assessment in Pigs. Front Vet Sci 2016; 3:108. [PMID: 27965968 PMCID: PMC5124671 DOI: 10.3389/fvets.2016.00108] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/15/2016] [Indexed: 11/13/2022] Open
Abstract
There is a moral obligation to minimize pain in pigs used for human benefit. In livestock production, pigs experience pain caused by management procedures, e.g., castration and tail docking, injuries from fighting or poor housing conditions, “management diseases” like mastitis or streptococcal meningitis, and at parturition. Pigs used in biomedical research undergo procedures that are regarded as painful in humans, but do not receive similar levels of analgesia, and pet pigs also experience potentially painful conditions. In all contexts, accurate pain assessment is a prerequisite in (a) the estimation of the welfare consequences of noxious interventions and (b) the development of more effective pain mitigation strategies. This narrative review identifies the sources of pain in pigs, discusses the various assessment measures currently available, and proposes directions for future investigation.
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Affiliation(s)
- Sarah H Ison
- Animal Behaviour and Welfare, Animal and Veterinary Sciences, Scotland's Rural College (SRUC), Edinburgh, UK; Easter Bush Veterinary Centre, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, UK
| | - R Eddie Clutton
- Easter Bush Veterinary Centre, Royal (Dick) School of Veterinary Studies, The University of Edinburgh , Midlothian , UK
| | - Pierpaolo Di Giminiani
- Food and Rural Development, School of Agriculture, Newcastle University , Newcastle upon Tyne , UK
| | - Kenneth M D Rutherford
- Animal Behaviour and Welfare, Animal and Veterinary Sciences, Scotland's Rural College (SRUC) , Edinburgh , UK
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Thibault K, Rivière S, Lenkei Z, Férézou I, Pezet S. Orofacial Neuropathic Pain Leads to a Hyporesponsive Barrel Cortex with Enhanced Structural Synaptic Plasticity. PLoS One 2016; 11:e0160786. [PMID: 27548330 PMCID: PMC4993517 DOI: 10.1371/journal.pone.0160786] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 07/25/2016] [Indexed: 12/30/2022] Open
Abstract
Chronic pain is a long-lasting debilitating condition that is particularly difficult to treat due to the lack of identified underlying mechanisms. Although several key contributing processes have been described at the level of the spinal cord, very few studies have investigated the supraspinal mechanisms underlying chronic pain. Using a combination of approaches (cortical intrinsic imaging, immunohistochemical and behavioural analysis), our study aimed to decipher the nature of functional and structural changes in a mouse model of orofacial neuropathic pain, focusing on cortical areas involved in various pain components. Our results show that chronic neuropathic orofacial pain is associated with decreased haemodynamic responsiveness to whisker stimulation in the barrel field cortex. This reduced functional activation is likely due to the increased basal neuronal activity (measured indirectly using cFos and phospho-ERK immunoreactivity) observed in several cortical areas, including the contralateral barrel field, motor and cingulate cortices. In the same animals, immunohistochemical analysis of markers for active pre- or postsynaptic elements (Piccolo and phospho-Cofilin, respectively) revealed an increased immunofluorescence in deep cortical layers of the contralateral barrel field, motor and cingulate cortices. These results suggest that long-lasting orofacial neuropathic pain is associated with exacerbated neuronal activity and synaptic plasticity at the cortical level.
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Affiliation(s)
- Karine Thibault
- Brain Plasticity Unit, ESPCI, PSL Research University, 10 rue Vauquelin, 75005, Paris, France
- Centre National de la Recherche Scientifique, UMR 8249, 75005, Paris, France
| | - Sébastien Rivière
- Brain Plasticity Unit, ESPCI, PSL Research University, 10 rue Vauquelin, 75005, Paris, France
- Centre National de la Recherche Scientifique, UMR 8249, 75005, Paris, France
| | - Zsolt Lenkei
- Brain Plasticity Unit, ESPCI, PSL Research University, 10 rue Vauquelin, 75005, Paris, France
- Centre National de la Recherche Scientifique, UMR 8249, 75005, Paris, France
| | - Isabelle Férézou
- Brain Plasticity Unit, ESPCI, PSL Research University, 10 rue Vauquelin, 75005, Paris, France
- Centre National de la Recherche Scientifique, UMR 8249, 75005, Paris, France
| | - Sophie Pezet
- Brain Plasticity Unit, ESPCI, PSL Research University, 10 rue Vauquelin, 75005, Paris, France
- Centre National de la Recherche Scientifique, UMR 8249, 75005, Paris, France
- * E-mail:
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Nag S, Mokha SS. Activation of the trigeminal α2-adrenoceptor produces sex-specific, estrogen dependent thermal antinociception and antihyperalgesia using an operant pain assay in the rat. Behav Brain Res 2016; 314:152-8. [PMID: 27506651 DOI: 10.1016/j.bbr.2016.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 01/04/2023]
Abstract
Higher prevalence of several pain disorders in women and sexual dimorphism in G-protein coupled receptor-induced analgesia has been reported. We have previously shown that α2-adrenoceptor-induced antinociception is sex-specific and attenuated by estrogen in the female rat. However, this evidence was obtained using reflexive withdrawal-based nociceptive assays conducted on restrained animals that may not involve cerebral processing. Hence, we evaluated whether activation of the trigeminal α2-adrenoceptor produces sex-specific antinociceptive and antihyperalgesic effects in the orofacial region of the rat using a reward conflict-based operant paradigm in which animals must tolerate nociceptive thermal stimulation to be rewarded. Male and ovariectomized (OVX) Sprague-Dawley rats were implanted intracisternally with a PE10 cannula for drug injections. A group of OVX rats (OVX+E) was administered subcutaneously with estradiol 48h before the test. Effect of clonidine, an α2-adrenoceptor agonist, was determined on the operant pain assay using a fully automated Orofacial Pain Assessment Device. Number of spout licks, thermode contacts, and amount of reward intake were automatically recorded by the ANY-maze software. Using acute pain modeling, clonidine produced a dose-dependent increase in all three parameters in male and OVX groups, however, it was ineffective in the OVX+E group. Similarly, using inflammatory pain modeling, clonidine significantly increased these parameters in carrageenan-treated male and OVX groups but not in the OVX+E group. Thus, α2-adrenoceptor activation produces sex-specific antinociception and antihyperalgesia and estrogen attenuates these effects in female rats using an operant pain assay. These findings may help the discovery of effective analgesics for each sex.
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Affiliation(s)
- Subodh Nag
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN 37208, United States.
| | - Sukhbir S Mokha
- Department of Neuroscience and Pharmacology, Meharry Medical College, Nashville, TN 37208, United States
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Rozas P, Lazcano P, Piña R, Cho A, Terse A, Pertusa M, Madrid R, Gonzalez-Billault C, Kulkarni AB, Utreras E. Targeted overexpression of tumor necrosis factor-α increases cyclin-dependent kinase 5 activity and TRPV1-dependent Ca2+ influx in trigeminal neurons. Pain 2016; 157:1346-1362. [PMID: 26894912 PMCID: PMC4868804 DOI: 10.1097/j.pain.0000000000000527] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We reported earlier that TNF-α, a proinflammatory cytokine implicated in many inflammatory disorders causing orofacial pain, increases the activity of Cdk5, a key kinase involved in brain development and function and recently found to be involved in pain signaling. To investigate a potential mechanism underlying inflammatory pain in trigeminal ganglia (TGs), we engineered a transgenic mouse model (TNF) that can conditionally overexpresses TNF-α upon genomic recombination by Cre recombinase. TNF mice were bred with Nav1.8-Cre mouse line that expresses the Cre recombinase in sensory neurons to obtain TNF-α:Nav1.8-Cre (TNF-α cTg) mice. Although TNF-α cTg mice appeared normal without any gross phenotype, they displayed a significant increase in TNF-α levels after activation of NFκB signaling in the TG. IL-6 and MCP-1 levels were also increased along with intense immunostaining for Iba1 and GFAP in TG, indicating the presence of infiltrating macrophages and the activation of satellite glial cells. TNF-α cTg mice displayed increased trigeminal Cdk5 activity, and this increase was associated with elevated levels of phospho-T407-TRPV1 and capsaicin-evocated Ca influx in cultured trigeminal neurons. Remarkably, this effect was prevented by roscovitine, an inhibitor of Cdk5, which suggests that TNF-α overexpression induced sensitization of the TRPV1 channel. Furthermore, TNF-α cTg mice displayed more aversive behavior to noxious thermal stimulation (45°C) of the face in an operant pain assessment device as compared with control mice. In summary, TNF-α overexpression in the sensory neurons of TNF-α cTg mice results in inflammatory sensitization and increased Cdk5 activity; therefore, this mouse model would be valuable for investigating the mechanism of TNF-α involved in orofacial pain.
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Affiliation(s)
- Pablo Rozas
- Laboratory of Molecular and Cellular Mechanisms of Pain, Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Pablo Lazcano
- Laboratory of Molecular and Cellular Mechanisms of Pain, Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Ricardo Piña
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile
| | - Andrew Cho
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Anita Terse
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Maria Pertusa
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile
| | - Rodolfo Madrid
- Department of Biology, Faculty of Chemistry and Biology, University of Santiago de Chile, Santiago, Chile
| | - Christian Gonzalez-Billault
- Laboratory of Cellular and Neuronal Dynamics, Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Ashok B. Kulkarni
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Elias Utreras
- Laboratory of Molecular and Cellular Mechanisms of Pain, Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
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Mustafa G, Hou J, Tsuda S, Nelson R, Sinharoy A, Wilkie Z, Pandey R, Caudle RM, Neubert JK, Thompson FJ, Bose P. Trigeminal neuroplasticity underlies allodynia in a preclinical model of mild closed head traumatic brain injury (cTBI). Neuropharmacology 2016; 107:27-39. [PMID: 26972829 DOI: 10.1016/j.neuropharm.2016.03.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 03/07/2016] [Accepted: 03/08/2016] [Indexed: 01/10/2023]
Abstract
Post-traumatic headache (PTH) following TBI is a common and often persisting pain disability. PTH is often associated with a multimodal central pain sensitization on the skin surface described as allodynia. However, the particular neurobiology underlying cTBI-induced pain disorders are not known. These studies were performed to assess trigeminal sensory sensitization and to determine if sensitization measured behaviorally correlated with detectable changes in portions of the trigeminal sensory system (TSS), particularly trigeminal nucleus, thalamus, and sensory cortex. Thermal stimulation is particularly well suited to evaluate sensitization and was used in these studies. Recent advances in the use of reward/conflict paradigms permit use of operant measures of behavior, versus reflex-driven response behaviors, for thermal sensitization studies. Thus, to quantitate facial thermal sensitization (allodynia) in the setting of acute TBI, the current study utilized an operant orofacial pain reward/conflict testing paradigm to assess facial thermal sensitivity in uninjured control animals compared with those two weeks after cTBI in a rodent model. Significant reductions in facial contact/lick behaviors were observed in the TBI animals using either cool or warm challenge temperatures compared with behaviors in the normal animals. These facial thermal sensitizations correlated with detectable changes in multiple levels of the TSS. The immunohistochemical (IHC) studies revealed significant alterations in the expression of the serotonin (5-HT), neurokinin 1 receptor (NK1R), norepinephrine (NE), and gamma-aminobutyric acid (GABA) in the caudal trigeminal nucleus, thalamic VPL/VPM nucleus, and sensory cortex of the orofacial pain pathways. There was a strong correlation between increased expression of certain IHC markers and increased behavioral markers for facial sensitization. The authors conclude that TBI-induced changes observed in the TSS are consistent with the expression of generalized facial allodynia following cTBI. To our knowledge, this is the first report of orofacial sensitization correlated with changes in selected neuromodulators/neurotransmitters in the TSS following experimental mild TBI.
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Affiliation(s)
- Golam Mustafa
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA; Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA
| | - Jiamei Hou
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA; Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA
| | - Shigeharu Tsuda
- Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA
| | - Rachel Nelson
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA
| | - Ankita Sinharoy
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA
| | - Zachary Wilkie
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA
| | - Rahul Pandey
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, College of Dentistry, University of Florida, Gainesville, FL 32610-0244, USA
| | - John K Neubert
- Department of Orthodontics, College of Dentistry, University of Florida, Gainesville, FL 32610-0244, USA
| | - Floyd J Thompson
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA; Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA; Department of Neuroscience, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610-0244, USA
| | - Prodip Bose
- Brain Rehabilitation Research Center of Excellence, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608-1197, USA; Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0144, USA; Department of Neurology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610-0236, USA.
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Harte SE, Meyers JB, Donahue RR, Taylor BK, Morrow TJ. Mechanical Conflict System: A Novel Operant Method for the Assessment of Nociceptive Behavior. PLoS One 2016; 11:e0150164. [PMID: 26915030 PMCID: PMC4767889 DOI: 10.1371/journal.pone.0150164] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/10/2016] [Indexed: 11/19/2022] Open
Abstract
A new operant test for preclinical pain research, termed the Mechanical Conflict System (MCS), is presented. Rats were given a choice either to remain in a brightly lit compartment or to escape to a dark compartment by crossing an array of height-adjustable nociceptive probes. Latency to escape the light compartment was evaluated with varying probe heights (0, .5, 1, 2, 3, and 4 mm above compartment floor) in rats with neuropathic pain induced by constriction nerve injury (CCI) and in naive control rats. Escape responses in CCI rats were assessed following intraperitoneal administration of pregabalin (10 and 30 mg/kg), morphine (2.5 and 5 mg/kg), and the tachykinin NK1 receptor antagonist, RP 67580 (1 and 10 mg/kg). Results indicate that escape latency increased as a function of probe height in both naive and CCI rats. Pregabalin (10 and 30 mg/kg) and morphine (5 mg/kg), but not RP 67580, decreased latency to escape in CCI rats suggesting an antinociceptive effect. In contrast, morphine (10 mg/kg) but not pregabalin (30 mg/kg) increased escape latency in naive rats suggesting a possible anxiolytic action of morphine in response to light-induced fear. No order effects following multiple test sessions were observed. We conclude that the MCS is a valid method to assess behavioral signs of affective pain in rodents.
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Affiliation(s)
- Steven E. Harte
- Department of Anesthesiology, Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
- * E-mail:
| | - Jessica B. Meyers
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
| | - Renee R. Donahue
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Bradley K. Taylor
- Department of Physiology, University of Kentucky, Lexington, Kentucky, United States of America
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Thomas J. Morrow
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, United States of America
- Neurology Service, Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, United States of America
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Jendryke T, Prochazkova M, Hall BE, Nordmann GC, Schladt M, Milenkovic VM, Kulkarni AB, Wetzel CH. TRPV1 function is modulated by Cdk5-mediated phosphorylation: insights into the molecular mechanism of nociception. Sci Rep 2016; 6:22007. [PMID: 26902776 PMCID: PMC4763283 DOI: 10.1038/srep22007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 02/05/2016] [Indexed: 01/19/2023] Open
Abstract
TRPV1 is a polymodally activated cation channel acting as key receptor in nociceptive neurons. Its function is strongly affected by kinase-mediated phosphorylation leading to hyperalgesia and allodynia. We present behavioral and molecular data indicating that TRPV1 is strongly modulated by Cdk5-mediated phosphorylation at position threonine-407(mouse)/T406(rat). Increasing or decreasing Cdk5 activity in genetically engineered mice has severe consequences on TRPV1-mediated pain perception leading to altered capsaicin consumption and sensitivity to heat. To understand the molecular and structural/functional consequences of TRPV1 phosphorylation, we generated various rTRPV1T406 receptor variants to mimic phosphorylated or dephosphorylated receptor protein. We performed detailed functional characterization by means of electrophysiological whole-cell and single-channel recordings as well as Ca2+-imaging and challenged recombinant rTRPV1 receptors with capsaicin, low pH, or heat. We found that position T406 is critical for the function of TRPV1 by modulating ligand-sensitivity, activation, and desensitization kinetics as well as voltage-dependence. Based on high resolution structures of TRPV1, we discuss T406 being involved in the molecular transition pathway, its phosphorylation leading to a conformational change and influencing the gating of the receptor. Cdk5-mediated phosphorylation of T406 can be regarded as an important molecular switch modulating TRPV1-related behavior and pain sensitivity.
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Affiliation(s)
- Thomas Jendryke
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Michaela Prochazkova
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bradford E Hall
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Grégory C Nordmann
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Moritz Schladt
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Vladimir M Milenkovic
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
| | - Ashok B Kulkarni
- Functional Genomics Section, Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Christian H Wetzel
- Molecular Neurosciences, Department of Psychiatry and Psychotherapy, University of Regensburg, 93053 Regensburg, Germany
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Hitomi S, Ono K, Yamaguchi K, Terawaki K, Imai R, Kubota K, Omiya Y, Hattori T, Kase Y, Inenaga K. The traditional Japanese medicine hangeshashinto alleviates oral ulcer-induced pain in a rat model. Arch Oral Biol 2016; 66:30-7. [PMID: 26878477 DOI: 10.1016/j.archoralbio.2016.02.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 12/15/2015] [Accepted: 02/01/2016] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Recent studies have demonstrated that mouthwash made with the traditional Japanese medicine hangeshashinto exhibits anti-inflammatory action and alleviates oral mucositis scores, including pain complaints, in patients undergoing chemoradiotherapy. However, no study has demonstrated the mechanism underlying how hangeshashinto provides pain relief in oral ulcers. DESIGN The analgesic effects on pain-related behaviors following the topical application of hangeshashinto were evaluated in an oral ulcer rat model treated with acetic acid using recently developed methods. Indomethacin, the representative anti-inflammatory agent, was intraperitoneally administered. The tissue permeability of the oral mucosa was histologically evaluated after applying the fluorescent substance FluoroGold. RESULTS The topical application of hangeshashinto in ulcerative oral mucosa suppressed mechanical pain hypersensitivity over 60 min, without any effects on healthy mucosa. The same drug application also inhibited oral ulcer-induced spontaneous pain. Indomethacin administration failed to block the mechanical pain hypersensitivity, though it did largely block spontaneous pain. Topical anesthesia with lidocaine showed hyposensitivity to mechanical stimulation in healthy mucosa. In the ulcer regions in which the oral epithelial barrier was destroyed, deep parenchyma was stained with FluoroGold, in contrast to healthy oral mucosa, in which staining was limiting to the superficial site. CONCLUSIONS Hangeshashinto leads to long-lasting analgesic effects, specifically in the ulcer region by destroying the epithelial barrier. Hangeshashinto alleviates oral ulcer-induced pain in inflammation-dependent and/or independent manner.
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Affiliation(s)
- Suzuro Hitomi
- Division of Physiology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
| | - Kentaro Ono
- Division of Physiology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan.
| | - Kiichiro Yamaguchi
- Division of Physiology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan; Division of Dental Anesthesiology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
| | - Kiyoshi Terawaki
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., 3586 Yoshihara, Amicho, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Ryota Imai
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., 3586 Yoshihara, Amicho, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Kunitsugu Kubota
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., 3586 Yoshihara, Amicho, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Yuji Omiya
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., 3586 Yoshihara, Amicho, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Tomohisa Hattori
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., 3586 Yoshihara, Amicho, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Yoshio Kase
- Tsumura Research Laboratories, Kampo Scientific Strategies Division, Tsumura & Co., 3586 Yoshihara, Amicho, Inashiki-gun, Ibaraki 300-1192, Japan
| | - Kiyotoshi Inenaga
- Division of Physiology, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, Fukuoka 803-8580, Japan
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Warner E, Krivitsky R, Cone K, Atherton P, Pitre T, Lanpher J, Giuvelis D, Bergquist I, King T, Bilsky EJ, Stevenson GW. Evaluation of a Postoperative Pain-Like State on Motivated Behavior in Rats: Effects of Plantar Incision on Progressive-Ratio Food-Maintained Responding. Drug Dev Res 2015; 76:432-41. [PMID: 26494422 PMCID: PMC4715615 DOI: 10.1002/ddr.21284] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 10/03/2015] [Indexed: 01/01/2023]
Abstract
There has been recent interest in characterizing the effects of pain-like states on motivated behaviors in order to quantify how pain modulates goal-directed behavior and the persistence of that behavior. The current set of experiments assessed the effects of an incisional postoperative pain manipulation on food-maintained responding under a progressive-ratio (PR) operant schedule. Independent variables included injury state (plantar incision or anesthesia control) and reinforcer type (grain pellet or sugar pellet); dependent variables were tactile sensory thresholds and response breakpoint. Once responding stabilized on the PR schedule, separate groups of rats received a single ventral hind paw incision or anesthesia (control condition). Incision significantly reduced breakpoints in rats responding for grain, but not sugar. In rats responding for sugar, tactile hypersensitivity recovered within 24 hr, indicating a faster recovery of incision-induced tactile hypersensitivity compared to rats responding for grain, which demonstrated recovery at PD2. The NSAID analgesic, diclofenac (5.6 mg/kg) completely restored incision-depressed PR operant responding and tactile sensitivity at 3 hr following incision. The PR schedule differentiated between sucrose and grain, suggesting that relative reinforcing efficacy may be an important determinant in detecting pain-induced changes in motivated behavior.
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Affiliation(s)
- Emily Warner
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Rebecca Krivitsky
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Katherine Cone
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Phillip Atherton
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Travis Pitre
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Janell Lanpher
- Department of Psychology, University of New England, Biddeford, ME, 04005
| | - Denise Giuvelis
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
| | - Ivy Bergquist
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
| | - Tamara King
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
- Center for Excellence in the Neurosciences, University of New England, ME, 04005
| | - Edward J. Bilsky
- Department of Biomedical Sciences, University of New England College of Osteopathic Medicine, Biddeford, ME, 04005
- Center for Excellence in the Neurosciences, University of New England, ME, 04005
| | - Glenn W. Stevenson
- Department of Psychology, University of New England, Biddeford, ME, 04005
- Center for Excellence in the Neurosciences, University of New England, ME, 04005
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Miller LL, Altarifi AA, Negus SS. Effects of repeated morphine on intracranial self-stimulation in male rats in the absence or presence of a noxious pain stimulus. Exp Clin Psychopharmacol 2015; 23:405-14. [PMID: 26375515 PMCID: PMC4578993 DOI: 10.1037/pha0000042] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Research on opioid analgesics such as morphine suggests that expression of abuse-related effects increases with repeated exposure. Repeated exposure to opioids often occurs clinically in the context of pain management, and a major concern for clinicians is the risk of iatrogenic addiction and dependence in patients receiving opioids for treatment of pain. This study compared abuse-related morphine effects in male rats in an intracranial self-stimulation (ICSS) procedure after repeated treatment either with morphine alone or with morphine in combination with a repeated noxious stimulus (intraperitoneal administration of dilute acid). The study also permitted comparison of morphine potency and effectiveness to block acid-induced depression of ICSS (antinociception) and to produce enhanced facilitation of ICSS (abuse-related effect). There were 3 main findings. First, initial morphine exposure to drug naïve rats did not produce abuse-related ICSS facilitation. Second, repeated daily treatment with 3.2 mg/kg/day morphine for 6 days increased expression of ICSS facilitation. This occurred whether morphine was administered in the absence or presence of the noxious stimulus. Finally, a lower dose of 1.0 mg/kg/day morphine was sufficient to produce antinociception during repeated acid treatment, but this lower dose did not reliably increase abuse-related morphine effects. Taken together, these results suggest that prior morphine exposure can increase abuse liability of subsequent morphine treatments even when that morphine exposure occurs in the context of a pain state. However, it may be possible to relieve pain with relatively low morphine doses that do not produce increases in abuse-related morphine effects.
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Affiliation(s)
- Laurence L. Miller
- Department of Psychological Science, Georgia Regents University, Augusta GA, USA
| | - Ahmad A. Altarifi
- Department of Pharmacology, Jordan University of Science and Technology, Irbid, Jordan
| | - S. Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond VA, USA
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Widmer CG, Morris-Wiman J. Assessment of incising ethology in the absence and presence of jaw muscle hyperalgesia in a mouse home cage environment. Physiol Behav 2015; 149:229-38. [PMID: 26074204 DOI: 10.1016/j.physbeh.2015.06.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 05/18/2015] [Accepted: 06/10/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Assessment of oral motor behavior in a mouse is challenging due to the lack of currently available techniques that are non-invasive and allow long-term assessment in a home cage environment. The purpose of this study was to evaluate incising behavior using mouse chow attached to a three-dimensional force transducer that was mounted on the existing home cage. In addition, a persistent hyperalgesia condition was introduced to evaluate the sensitivity of the technique to identify incising behavioral changes. METHODS Incising activity of CD-1 male and female mice (n=48) was evaluated over a 24 hour recording session during four baseline and six longitudinal hyperalgesia assessment sessions using custom written software. A pre-clinical persistent pain model was used to induce hyperalgesia in the masseter muscle by repetitive acidic saline injections. Sex and age differences were evaluated for multiple incising variables during both light and dark cycles during baseline and hyperalgesia conditions. RESULTS Significant sex differences were found for multiple incising variables but not for age. Discrete incising frequencies were identified in the range of 4.6-10.4 Hz and were reproducibly found in both female and male mice. A significant shift to lower incising frequencies was observed after repetitive acidic saline injections compared to neutral saline injections. This shift to lower frequencies of incising returned to baseline levels after approximately four weeks but was statistically longer in female compared to male mice. Significant differences were also found for chow intake (reduced) and weight change during the hyperalgesia condition. No significant differences were found for total number of incisions or number of incising episodes per day or incising force. CONCLUSIONS The findings from this study support the use of recording three dimensional incising forces as a sensitive measure of incising behavior. This novel technique allowed the identification of specific incising variables that were differentially affected in female and male mice during a persistent hyperalgesia. The data were collected in the home cage environment with minimal bias such as experimenter interaction. Similar to other dental pain studies, mice were able to maintain normal incising activity levels per day (total incisions, total number of incising episodes) even in the presence of hyperalgesia.
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Affiliation(s)
- C G Widmer
- Dept. of Orthodontics, Box 100444, JHMHSC, University of Florida, Gainesville, FL 32610-0444, USA.
| | - J Morris-Wiman
- Biomedical Sciences, West Virginia School of Osteopathic Medicine, 400 North Lee St., Lewisburg, VA 24901, USA.
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Anderson EM, Reeves T, Kapernaros K, Neubert JK, Caudle RM. Phosphorylation of the N-methyl-d-aspartate receptor is increased in the nucleus accumbens during both acute and extended morphine withdrawal. J Pharmacol Exp Ther 2015; 355:496-505. [PMID: 26377910 DOI: 10.1124/jpet.115.227629] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022] Open
Abstract
Opioid withdrawal causes a dysphoric state that can lead to complications in pain patients and can propagate use in drug abusers and addicts. Opioid withdrawal changes the activity of neurons in the nucleus accumbens, an area rich in both opioid-binding mu opioid receptors and glutamate-binding NMDA receptors. Because the accumbens is an area important for reward and aversion, plastic changes in this area during withdrawal could alter future behaviors in animals. We discovered an increase in phosphorylation of serine 897 in the NR1 subunit of the NMDA receptor (pNR1) during acute morphine withdrawal. This serine can be phosphorylated by protein kinase A (PKA) and dephosphorylated by calcineurin. We next demonstrated that this increased pNR1 change is associated with an increase in NR1 surface expression. NR1 surface expression and pNR1 levels during acute withdrawal were both reduced by the NMDA receptor antagonist MK-801 (dizocilpine hydrogen maleate) and the PKA inhibitor H-89(N-[2-[[3-(4-bromophenyl)-2-propenyl]amino]ethyl]-5-isoquinolinesulfonamide dihydrochloride hydrate). We also found that pNR1 levels remained high after an extended morphine withdrawal period of 2 months, correlated with reward-seeking behavior for palatable food, and were associated with a decrease in accumbal calcineurin levels. These data suggest that NR1 phosphorylation changes during the acute withdrawal phase can be long lasting and may reflect a permanent change in NMDA receptors in the accumbens. These altered NMDA receptors in the accumbens could play a role in long-lasting behaviors associated with reward and opioid use.
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Affiliation(s)
- Ethan M Anderson
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida (E.M.A., R.M.C.); Department of Neuroscience, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, Florida (E.M.A., R.M.C.); University of Florida, Gainesville, Florida (T.R., K.K.); and UF College of Dentistry, Department of Orthodontics, Gainesville, Florida (J.K.N.)
| | - Turi Reeves
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida (E.M.A., R.M.C.); Department of Neuroscience, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, Florida (E.M.A., R.M.C.); University of Florida, Gainesville, Florida (T.R., K.K.); and UF College of Dentistry, Department of Orthodontics, Gainesville, Florida (J.K.N.)
| | - Katherine Kapernaros
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida (E.M.A., R.M.C.); Department of Neuroscience, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, Florida (E.M.A., R.M.C.); University of Florida, Gainesville, Florida (T.R., K.K.); and UF College of Dentistry, Department of Orthodontics, Gainesville, Florida (J.K.N.)
| | - John K Neubert
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida (E.M.A., R.M.C.); Department of Neuroscience, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, Florida (E.M.A., R.M.C.); University of Florida, Gainesville, Florida (T.R., K.K.); and UF College of Dentistry, Department of Orthodontics, Gainesville, Florida (J.K.N.)
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, Florida (E.M.A., R.M.C.); Department of Neuroscience, University of Florida College of Medicine, McKnight Brain Institute, Gainesville, Florida (E.M.A., R.M.C.); University of Florida, Gainesville, Florida (T.R., K.K.); and UF College of Dentistry, Department of Orthodontics, Gainesville, Florida (J.K.N.)
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Abd-Elsayed AA, Ikeda R, Jia Z, Ling J, Zuo X, Li M, Gu JG. KCNQ channels in nociceptive cold-sensing trigeminal ganglion neurons as therapeutic targets for treating orofacial cold hyperalgesia. Mol Pain 2015; 11:45. [PMID: 26227020 PMCID: PMC4521366 DOI: 10.1186/s12990-015-0048-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 07/22/2015] [Indexed: 12/03/2022] Open
Abstract
Background Hyperexcitability of nociceptive afferent fibers is an underlying mechanism of neuropathic pain and ion channels involved in neuronal excitability are potentially therapeutic targets. KCNQ channels, a subfamily of voltage-gated K+ channels mediating M-currents, play a key role in neuronal excitability. It is unknown whether KCNQ channels are involved in the excitability of nociceptive cold-sensing trigeminal afferent fibers and if so, whether they are therapeutic targets for orofacial cold hyperalgesia, an intractable trigeminal neuropathic pain. Methods Patch-clamp recording technique was used to study M-currents and neuronal excitability of cold-sensing trigeminal ganglion neurons. Orofacial operant behavioral assessment was performed in animals with trigeminal neuropathic pain induced by oxaliplatin or by infraorbital nerve chronic constrictive injury. Results We showed that KCNQ channels were expressed on and mediated M-currents in rat nociceptive cold-sensing trigeminal ganglion (TG) neurons. The channels were involved in setting both resting membrane potentials and rheobase for firing action potentials in these cold-sensing TG neurons. Inhibition of KCNQ channels by linopirdine significantly decreased resting membrane potentials and the rheobase of these TG neurons. Linopirdine directly induced orofacial cold hyperalgesia when the KCNQ inhibitor was subcutaneously injected into rat orofacial regions. On the other hand, retigabine, a KCNQ channel potentiator, suppressed the excitability of nociceptive cold-sensing TG neurons. We further determined whether KCNQ channel could be a therapeutic target for orofacial cold hyperalgesia. Orofacial cold hyperalgesia was induced in rats either by the administration of oxaliplatin or by infraorbital nerve chronic constrictive injury. Using the orofacial operant test, we showed that retigabine dose-dependently alleviated orofacial cold hyperalgesia in both animal models. Conclusion Taken together, these findings indicate that KCNQ channel plays a significant role in controlling cold sensitivity and is a therapeutic target for alleviating trigeminal neuropathic pain that manifests orofacial cold hyperalgesia.
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Affiliation(s)
- Alaa A Abd-Elsayed
- Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA. .,Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
| | - Ryo Ikeda
- Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA. .,Department of Orthopedic Surgery, Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo, 105-8461, Japan.
| | - Zhanfeng Jia
- Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA. .,Department of Pharmacology, Hebei Medical University, 361 East Zhongshan Road, Shijiazhuang, 050017, Hebei, China.
| | - Jennifer Ling
- Department of Anesthesiology and Perioperative Medicine, College of Medicine, University of Alabama at Birmingham, 901 19th Street South, BMR II 210, Birmingham, AL, 35294, USA. .,Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA.
| | - Xiaozhuo Zuo
- Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA.
| | - Min Li
- Department of Neuroscience and High Throughput Biology Center, Johns Hopkins University School of Medicine, 733 N. Broadway 311 BRB, Baltimore, MD, 21205, USA. .,GlaxoSmithKline, New York, NY, USA.
| | - Jianguo G Gu
- Department of Anesthesiology and Perioperative Medicine, College of Medicine, University of Alabama at Birmingham, 901 19th Street South, BMR II 210, Birmingham, AL, 35294, USA. .,Department of Anesthesiology and the Graduate Program in Neuroscience, The University of Cincinnati College of Medicine, PO Box 670531, 231 Albert Sabin Way, Cincinnati, OH, 45267-0531, USA.
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Rohrs EL, Kloefkorn HE, Lakes EH, Jacobs BY, Neubert JK, Caudle RM, Allen KD. A novel operant-based behavioral assay of mechanical allodynia in the orofacial region of rats. J Neurosci Methods 2015; 248:1-6. [PMID: 25823368 DOI: 10.1016/j.jneumeth.2015.03.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND Detecting behaviors related to orofacial pain in rodent models often relies on subjective investigator grades or methods that place the animal in a stressful environment. In this study, an operant-based behavioral assay is presented for the assessment of orofacial tactile sensitivity in the rat. NEW METHODS In the testing chamber, rats are provided access to a sweetened condensed milk bottle; however, a 360° array of stainless steel wire loops impedes access. To receive the reward, an animal must engage the wires across the orofacial region. Contact with the bottle triggers a motor, requiring the animal to accept increasing pressure on the face during the test. To evaluate this approach, tolerated bottle distance was measured for 10 hairless Sprague Dawley rats at baseline and 30 min after application of capsaicin cream (0.1%) to the face. The experiment was repeated to evaluate the ability of morphine to reverse this effect. RESULTS The application of capsaicin cream reduced tolerated bottle distance measures relative to baseline (p<0.05). As long as morphine did not cause reduced participation due to sedation, subcutaneous morphine dosing reduced the effects of capsaicin (p<0.001). Comparison with existing method: For behavioral tests, experimenters often make subjective decisions of an animal's response. Operant methods can reduce these effects by measuring an animal's selection in a reward-conflict decision. Herein, a method to measure orofacial sensitivity is presented using an operant system. CONCLUSIONS This operant device allows for consistent measurement of heightened tactile sensitivity in the orofacial regions of the rat.
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Affiliation(s)
- Eric L Rohrs
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive Biomedical Sciences Building, JG56, Gainesville, FL, 32610, United States.
| | - Heidi E Kloefkorn
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive Biomedical Sciences Building, JG56, Gainesville, FL, 32610, United States.
| | - Emily H Lakes
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive Biomedical Sciences Building, JG56, Gainesville, FL, 32610, United States; Institute for Cell Engineering and Regenerative Medicine, University of Florida, Gainesville, FL, United States.
| | - Brittany Y Jacobs
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive Biomedical Sciences Building, JG56, Gainesville, FL, 32610, United States.
| | - John K Neubert
- Department of Orthodontics, University of Florida, Gainesville, FL, United States; Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, FL, United States.
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida, Gainesville, FL, United States; Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, FL, United States.
| | - Kyle D Allen
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive Biomedical Sciences Building, JG56, Gainesville, FL, 32610, United States; Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, FL, United States; Institute for Cell Engineering and Regenerative Medicine, University of Florida, Gainesville, FL, United States; Nanoscience Institute for Medical and Engineering Technology, University of Florida, Gainesville, FL, United States.
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