1
|
Cao B, Xu Q, Shi Y, Zhao R, Li H, Zheng J, Liu F, Wan Y, Wei B. Pathology of pain and its implications for therapeutic interventions. Signal Transduct Target Ther 2024; 9:155. [PMID: 38851750 PMCID: PMC11162504 DOI: 10.1038/s41392-024-01845-w] [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: 05/12/2023] [Revised: 04/08/2024] [Accepted: 04/25/2024] [Indexed: 06/10/2024] Open
Abstract
Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.
Collapse
Affiliation(s)
- Bo Cao
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
| | - Qixuan Xu
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
- Medical School of Chinese PLA, Beijing, 100853, China
| | - Yajiao Shi
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China
| | - Ruiyang Zhao
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
- Medical School of Chinese PLA, Beijing, 100853, China
| | - Hanghang Li
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China
- Medical School of Chinese PLA, Beijing, 100853, China
| | - Jie Zheng
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China
| | - Fengyu Liu
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China.
| | - You Wan
- Neuroscience Research Institute and Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience, Ministry of Education/National Health Commission, Peking University, Beijing, 100191, China.
| | - Bo Wei
- Department of General Surgery, First Medical Center, Chinese PLA General Hospital, Beijing, 100853, China.
| |
Collapse
|
2
|
Navratilova E, Qu C, Ji G, Neugebauer V, Guerrero M, Rosen H, Roberts E, Porreca F. Opposing Effects on Descending Control of Nociception by µ and κ Opioid Receptors in the Anterior Cingulate Cortex. Anesthesiology 2024; 140:272-283. [PMID: 37725756 DOI: 10.1097/aln.0000000000004773] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/21/2023]
Abstract
BACKGROUND The efficiency of descending pain modulation, commonly assessed with the conditioned pain modulation procedure, is diminished in patients with chronic pain. The authors hypothesized that the efficiency of pain modulation is controlled by cortical opioid circuits. METHODS This study evaluated the effects of µ opioid receptor activation in the anterior cingulate cortex on descending control of nociception, a preclinical correlate of conditioned pain modulation, in male Sprague-Dawley rats with spinal nerve ligation-induced chronic pain or in sham-operated controls. Additionally, the study explored the consequences of respective activation or inhibition of κ opioid receptor in the anterior cingulate cortex of naive rats or animals with neuropathic pain. Descending control of nociception was measured as the hind paw withdrawal response to noxious pressure (test stimulus) in the absence or presence of capsaicin injection in the forepaw (conditioning stimulus). RESULTS Descending control of nociception was diminished in the ipsilateral, but not contralateral, hind paw of rats with spinal nerve ligation. Bilateral administration of morphine in the anterior cingulate cortex had no effect in shams but restored diminished descending control of nociception without altering hypersensitivity in rats with neuropathic pain. Bilateral anterior cingulate cortex microinjection of κ opioid receptor antagonists, including nor-binaltorphimine and navacaprant, also re-established descending control of nociception in rats with neuropathic pain without altering hypersensitivity and with no effect in shams. Conversely, bilateral injection of a κ opioid receptor agonist, U69,593, in the anterior cingulate cortex of naive rats inhibited descending control of nociception without altering withdrawal thresholds. CONCLUSIONS Anterior cingulate cortex κ opioid receptor activation therefore diminishes descending control of nociception both in naive animals and as an adaptive response to chronic pain, likely by enhancing net descending facilitation. Descending control of nociception can be restored by activation of μ opioid receptors in the anterior cingulate cortex, but also by κ opioid receptor antagonists, providing a nonaddictive alternative to opioid analgesics. Navacaprant is now in advanced clinical trials. EDITOR’S PERSPECTIVE
Collapse
Affiliation(s)
- Edita Navratilova
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona
| | - Chaoling Qu
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona
| | - Guangchen Ji
- Department of Pharmacology and Neuroscience and Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience and Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Miguel Guerrero
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Hugh Rosen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Edward Roberts
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California
| | - Frank Porreca
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona
| |
Collapse
|
3
|
Bharadwaj VN, Sahbaie P, Shi X, Irvine KA, Yeomans DC, Clark JD. Effect of Voluntary Exercise on Endogenous Pain Control Systems and Post-traumatic Headache in Mice. THE JOURNAL OF PAIN 2023; 24:1859-1874. [PMID: 37271350 DOI: 10.1016/j.jpain.2023.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 05/16/2023] [Accepted: 05/30/2023] [Indexed: 06/06/2023]
Abstract
Traumatic brain injury (TBI) can cause acute and chronic pain along with motor, cognitive, and emotional problems. Although the mechanisms are poorly understood, previous studies suggest disruptions in endogenous pain modulation may be involved. Voluntary exercise after a TBI has been shown to reduce some consequences of injury including cognitive impairment. We hypothesized, therefore, that voluntary exercise could augment endogenous pain control systems in a rodent model of TBI. For these studies, we used a closed-head impact procedure in male mice modeling mild TBI. We investigated the effect of voluntary exercise on TBI-induced hindpaw nociceptive sensitization, diffuse noxious inhibitory control failure, and periorbital sensitization after bright light stress, a model of post-traumatic headache. Furthermore, we investigated the effects of exercise on memory, circulating markers of brain injury, neuroinflammation, and spinal cord gene expression. We observed that exercise significantly reduced TBI-induced hindpaw allodynia and periorbital allodynia in the first week following TBI. We also showed that exercise improved the deficits associated with diffuse noxious inhibitory control and reduced bright light stress-induced allodynia up to 2 months after TBI. In addition, exercise preserved memory and reduced TBI-induced increases in spinal BDNF, CXCL1, CXCL2, and prodynorphin expression, all genes previously linked to TBI-induced nociceptive sensitization. Taken together, our observations suggest that voluntary exercise may reduce pain after TBI by reducing TBI-induced changes in nociceptive signaling and preserving endogenous pain control systems. PERSPECTIVE: This article evaluates the effects of exercise on pain-related behaviors in a preclinical model of traumatic brain injury (TBI). The findings show that exercise reduces nociceptive sensitization, loss of diffuse noxious inhibitory control, memory deficits, and spinal nociception-related gene expression after TBI. Exercise may reduce or prevent pain after TBI.
Collapse
Affiliation(s)
- Vimala N Bharadwaj
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, California.
| | - Peyman Sahbaie
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, California; Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Xiaoyou Shi
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, California; Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - Karen-Amanda Irvine
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, California; Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| | - David C Yeomans
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, California
| | - J David Clark
- Department of Anesthesia, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, California; Anesthesiology Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California
| |
Collapse
|
4
|
Huo J, Du F, Duan K, Yin G, Liu X, Ma Q, Dong D, Sun M, Hao M, Su D, Huang T, Ke J, Lai S, Zhang Z, Guo C, Sun Y, Cheng L. Identification of brain-to-spinal circuits controlling the laterality and duration of mechanical allodynia in mice. Cell Rep 2023; 42:112300. [PMID: 36952340 DOI: 10.1016/j.celrep.2023.112300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 12/22/2022] [Accepted: 03/07/2023] [Indexed: 03/24/2023] Open
Abstract
Mechanical allodynia (MA) represents one prevalent symptom of chronic pain. Previously we and others have identified spinal and brain circuits that transmit or modulate the initial establishment of MA. However, brain-derived descending pathways that control the laterality and duration of MA are still poorly understood. Here we report that the contralateral brain-to-spinal circuits, from Oprm1 neurons in the lateral parabrachial nucleus (lPBNOprm1), via Pdyn neurons in the dorsal medial regions of hypothalamus (dmHPdyn), to the spinal dorsal horn (SDH), act to prevent nerve injury from inducing contralateral MA and reduce the duration of bilateral MA induced by capsaicin. Ablating/silencing dmH-projecting lPBNOprm1 neurons or SDH-projecting dmHPdyn neurons, deleting Dyn peptide from dmH, or blocking spinal κ-opioid receptors all led to long-lasting bilateral MA. Conversely, activation of dmHPdyn neurons or their axonal terminals in SDH can suppress sustained bilateral MA induced by lPBN lesion.
Collapse
Affiliation(s)
- Jiantao Huo
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Feng Du
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kaifang Duan
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guangjuan Yin
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xi Liu
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Quan Ma
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dong Dong
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mengge Sun
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Mei Hao
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Dongmei Su
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Tianwen Huang
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China
| | - Jin Ke
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China
| | - Shishi Lai
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China
| | - Zhi Zhang
- Division of Life Sciences and Medicine, CAS Key Laboratory of Brain Function and Diseases, University of Science and Technology of China, Hefei 230027, China
| | - Chao Guo
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Yuanjie Sun
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Longzhen Cheng
- Shenzhen Key Laboratory of Gene Regulation and Systems Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China; Department of Biology, Brain Research Center, Southern University of Science and Technology, Shenzhen 518055, China; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China.
| |
Collapse
|
5
|
Neural mechanisms underlying the conditioned pain modulation response: a narrative review of neuroimaging studies. Pain 2023; 164:e25-e46. [PMID: 36017881 DOI: 10.1097/j.pain.0000000000002716] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 04/25/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Processing spatially distributed nociceptive information is critical for survival. The conditioned pain modulation (CPM) response has become a common psychophysical test to examine pain modulation capabilities related to spatial filtering of nociceptive information. Neuroimaging studies have been conducted to elucidate the neural mechanisms underlying the CPM response in health and chronic pain states, yet their findings have not been critically reviewed and synthesized before. This narrative review presents a simplified overview of MRI methodology in relation to CPM assessments and summarizes the findings of neuroimaging studies on the CPM response. The summary includes functional MRI studies assessing CPM responses during scanning as well as functional and structural MRI studies correlating indices with CPM responses assessed outside of the scanner. The findings are discussed in relation to the suggested mechanisms for the CPM response. A better understanding of neural mechanisms underlying spatial processing of nociceptive information could advance both pain research and clinical use of the CPM response as a marker or a treatment target.
Collapse
|
6
|
Jennings EM, Sullivan LC, Jamshidi RJ, LoCoco PM, Smith HR, Chavera TS, Berg KA, Clarke WP. Age-related changes in peripheral nociceptor function. Neuropharmacology 2022; 216:109187. [PMID: 35835212 DOI: 10.1016/j.neuropharm.2022.109187] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/21/2022] [Accepted: 07/03/2022] [Indexed: 01/05/2023]
Abstract
Pain and pain management in the elderly population is a significant social and medical problem. Pain sensation is a complex phenomenon that typically involves activation of peripheral pain-sensing neurons (nociceptors) which send signals to the spinal cord and brain that are interpreted as pain, an unpleasant sensory experience. In this work, young (4-5 months) and aged (26-27 months) Fischer 344 x Brown Norway (F344xBN) rats were examined for nociceptor sensitivity to activation by thermal (cold and heat) and mechanical stimulation following treatment with inflammatory mediators and activators of transient receptor potential (TRP) channels. Unlike other senses that decrease in sensitivity with age, sensitivity of hindpaw nociceptors to thermal and mechanical stimulation was not different between young and aged F344xBN rats. Intraplantar injection of bradykinin (BK) produced greater thermal and mechanical allodynia in aged versus young rats, whereas only mechanical allodynia was greater in aged rats following injection of prostaglandin E2 (PGE2). Intraplantar injection of TRP channel activators, capsaicin (TRPV1), mustard oil (TRPA1) and menthol (TRPM8) each resulted in greater mechanical allodynia in aged versus young rats and capsaicin-induced heat allodynia was also greater in aged rats. A treatment-induced allodynia that was greater in young rats was never observed. The anti-allodynic effects of intraplantar injection of kappa and delta opioid receptor agonists, salvinorin-A and D-Pen2,D-Pen5]enkephalin (DPDPE), respectively, were greater in aged than young rats, whereas mu opioid receptor agonists, [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) and morphine, were not effective in aged rats. Consistent with these observations, in primary cultures of peripheral sensory neurons, inhibition of cAMP signaling in response to delta and kappa receptor agonists was greater in cultures derived from aged rats. By contrast, mu receptor agonists did not inhibit cAMP signaling in aged rats. Thus, age-related changes in nociceptors generally favor increased pain signaling in aged versus young rats, suggesting that changes in nociceptor sensitivity may play a role in the increased incidence of pain in the elderly population. These results also suggest that development of peripherally-restricted kappa or delta opioid receptor agonists may provide safer and effective pain relief for the elderly.
Collapse
Affiliation(s)
- Elaine M Jennings
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - Laura C Sullivan
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - Raehannah J Jamshidi
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - Peter M LoCoco
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - Hudson R Smith
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - Teresa S Chavera
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - Kelly A Berg
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA
| | - William P Clarke
- Department of Pharmacology, The University of Texas Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX, 78229-3900, USA.
| |
Collapse
|
7
|
Follansbee T, Domocos D, Nguyen E, Nguyen A, Bountouvas A, Velasquez L, Iodi Carstens M, Takanami K, Ross SE, Carstens E. Inhibition of itch by neurokinin 1 receptor (Tacr1) -expressing ON cells in the rostral ventromedial medulla in mice. eLife 2022; 11:69626. [PMID: 35972457 PMCID: PMC9381038 DOI: 10.7554/elife.69626] [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: 04/21/2021] [Accepted: 08/04/2022] [Indexed: 12/03/2022] Open
Abstract
The rostral ventromedial medulla (RVM) is important in descending modulation of spinal nociceptive transmission, but it is unclear if the RVM also modulates spinal pruriceptive transmission. RVM ON cells are activated by noxious algesic and pruritic stimuli and are pronociceptive. Many RVM-spinal projection neurons express the neurokinin-1 receptor (Tacr1), and ON-cells are excited by local administration of substance P (SP). We hypothesized that Tacr1-expressing RVM ON cells exert an inhibitory effect on itch opposite to their pronociceptive action. Intramedullary microinjection of SP significantly potentiated RVM ON cells and reduced pruritogen-evoked scratching while producing mild mechanical sensitization. Chemogenetic activation of RVM Tacr1-expressing RVM neurons also reduced acute pruritogen-evoked scratching. Optotagging experiments confirmed RVM Tacr1-expressing neurons to be ON cells. We conclude that Tacr1-expressing ON cells in RVM play a significant role in the modulation of pruriceptive transmission.
Collapse
Affiliation(s)
- Taylor Follansbee
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States.,Department of Neuroscience, Johns Hopkins University, Baltimore, United States
| | - Dan Domocos
- Department of Anatomy, Animal Physiology and Biophysics, University of Bucharest, Bucharest, Romania
| | - Eileen Nguyen
- Pittsburgh Center for Pain Research and Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
| | - Amanda Nguyen
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| | - Aristea Bountouvas
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| | - Lauren Velasquez
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| | - Mirela Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| | - Keiko Takanami
- Department of Environmental Life Science, National Nara Women University, Nara, Japan
| | - Sarah E Ross
- Pittsburgh Center for Pain Research and Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
| | - Earl Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, United States
| |
Collapse
|
8
|
Barger MK. Systematic Reviews to Inform Practice, January/February 2022. J Midwifery Womens Health 2022; 67:126-132. [DOI: 10.1111/jmwh.13334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 11/30/2022]
Affiliation(s)
- Mary K. Barger
- Midwifery researcher and consultant San Diego California
| |
Collapse
|
9
|
Alter BJ, Santosa H, Nguyen QH, Huppert TJ, Wasan AD. Offset analgesia is associated with opposing modulation of medial versus dorsolateral prefrontal cortex activations: A functional near-infrared spectroscopy study. Mol Pain 2022; 18:17448069221074991. [PMID: 35083928 PMCID: PMC9047820 DOI: 10.1177/17448069221074991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/20/2021] [Accepted: 12/29/2021] [Indexed: 12/02/2022] Open
Abstract
Offset analgesia is defined by a dramatic drop in perceived pain intensity with a relatively small decrease in noxious input. Although functional magnetic resonance imaging studies implicate subcortical descending inhibitory circuits during offset analgesia, the role of cortical areas remains unclear. The current study identifies cortical correlates of offset analgesia using functional near infrared spectroscopy (fNIRS). Twenty-four healthy volunteers underwent fNIRS scanning during offset (OS) and control (Con) heat stimuli applied to the forearm. After controlling for non-neural hemodynamic responses in superficial tissues, widespread increases in cortical oxygenated hemoglobin concentration were observed, reflecting cortical activation during heat pain. OS-Con contrasts revealed deactivations in bilateral medial prefrontal cortex (mPFC) and bilateral somatosensory cortex (SSC) associated with offset analgesia. Right dorsolateral prefrontal cortex (dlPFC) showed activation only during OS. These data demonstrate opposing cortical activation patterns during offset analgesia and support a model in which right dlPFC underlies ongoing evaluation of pain intensity change. With predictions of decreasing pain intensity, right dlPFC activation likely inhibits ascending noxious input via subcortical pathways resulting in SSC and mPFC deactivation. This study identifies cortical circuitry underlying offset analgesia and introduces the use of fNIRS to study pain modulation in an outpatient clinical environment.
Collapse
Affiliation(s)
- Benedict J. Alter
- Department of Anesthesiology and
Perioperative Medicine, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Hendrik Santosa
- Department of Radiology, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Quynh H. Nguyen
- Department of Anesthesiology and
Perioperative Medicine, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Theodore J. Huppert
- Department of Electrical and
Computer Engineering, University of
Pittsburgh, Pittsburgh, PA, USA
| | - Ajay D. Wasan
- Department of Anesthesiology and
Perioperative Medicine, University of
Pittsburgh, Pittsburgh, PA, USA
- Department of Psychiatry, University of
Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
10
|
Defrin R, Gruener H, Gaidukov E, Bondi M, Rachamim-Katz O, Ringler E, Blumen N, Zeilig G. From acute to long-term alterations in pain processing and modulation after spinal cord injury: mechanisms related to chronification of central neuropathic pain. Pain 2022; 163:e94-e105. [PMID: 33863855 DOI: 10.1097/j.pain.0000000000002315] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 04/10/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT A severe and debilitating consequence of a spinal cord injury (SCI) is central neuropathic pain (CNP). Our aim was to investigate the processes leading to CNP emergence and chronification by analyzing causal relationship over time between spinothalamic function, pain excitability, and pain inhibition after SCI. This longitudinal follow-up study included 53 patients with acute SCI and 20 healthy controls. Spinothalamic, pain excitability, and intrasegmental and extrasegmental pain inhibition indices were repeatedly evaluated at 1.5, 3, and 6 months post-SCI. Between- and within-group analyses were conducted among those patients who eventually developed CNP and those who did not. Healthy controls were evaluated twice for repeatability analysis. Patients who developed CNP, compared with those who did not, exhibited increased thermal thresholds (P < 0.05), reduced pain adaptation (P < 0.01), and conditioned pain modulation (P < 0.05), early post-injury, and the CNP group's manifestations remained worse throughout the follow-up. By contrast, allodynia frequency was initially similar across SCI groups, but gradually increased in the subacute phase onward only among the CNP group (P < 0.001), along with CNP emergence. Early worse spinothalamic and pain inhibition preceded CNP and predicted its occurrence, and early worse pain inhibition mediated the link between spinothalamic function and CNP. Crossover associations were observed between early and late pain inhibition and excitability. Inefficient intrasegmental and extrasegmental inhibition, possibly resulting from spinothalamic deafferentation, seems to ignite CNP chronification. Pain excitability probably contributes to CNP maintenance, possibly via further exhaustion of the inhibitory control. Preemptive treatment promoting antinociception early post-SCI may mitigate or prevent CNP.
Collapse
Affiliation(s)
- Ruth Defrin
- Department of Physical Therapy at Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Hila Gruener
- Department of Physical Therapy at Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Evgeni Gaidukov
- Department of Neurological Rehabilitation, Chaim Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
- Department of Rehabilitation Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Moshe Bondi
- Department of Neurological Rehabilitation, Chaim Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
- Department of Rehabilitation Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Orna Rachamim-Katz
- Barzilai Day Care Rehabilitation Unit, Barzilai Medical Center, Ashkelon, Israel
| | - Erez Ringler
- Department of Neurological Rehabilitation, Chaim Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
- Department of Rehabilitation Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nava Blumen
- Department of Neurological Rehabilitation, Chaim Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
- Department of Rehabilitation Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Gabi Zeilig
- Department of Neurological Rehabilitation, Chaim Sheba Medical Center, Tel Hashomer, Ramat Gan, Israel
- Department of Rehabilitation Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
11
|
Isa AS, Chetty S. Physiology and pathophysiology of chronic pain (Part I). SOUTHERN AFRICAN JOURNAL OF ANAESTHESIA AND ANALGESIA 2021. [DOI: 10.36303/sajaa.2021.27.6.2491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- AS Isa
- Department of Anaesthesiology and Critical Care, Faculty of Medicine and Health Sciences, Stellenbosch University,
South Africa
- Department of Human Physiology, Faculty of Basic Medical Sciences, College of Medical Sciences, Ahmadu Bello University,
Nigeria
| | - S Chetty
- Department of Anaesthesiology and Critical Care, Faculty of Medicine and Health Sciences, Stellenbosch University,
South Africa
| |
Collapse
|
12
|
Worthington A, Kalteniece A, Ferdousi M, D'Onofrio L, Dhage S, Azmi S, Adamson C, Hamdy S, Malik RA, Calcutt NA, Marshall AG. Spinal Inhibitory Dysfunction in Patients With Painful or Painless Diabetic Neuropathy. Diabetes Care 2021; 44:1835-1841. [PMID: 34385346 DOI: 10.2337/dc20-2797] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 05/13/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Impaired rate-dependent depression of the Hoffman reflex (HRDD) is a marker of spinal inhibitory dysfunction and has previously been associated with painful neuropathy in a proof-of-concept study in patients with type 1 diabetes. We have now undertaken an assessment of HRDD in patients with type 1 or type 2 diabetes. RESEARCH DESIGN AND METHODS A total of 148 participants, including 34 healthy control subjects, 42 patients with painful diabetic neuropathy, and 62 patients with diabetic neuropathy without pain, underwent an assessment of HRDD and a detailed assessment of peripheral neuropathy, including nerve conduction studies, corneal confocal microscopy, and thermal threshold testing. RESULTS Compared with healthy control subjects (P < 0.001) and patients without pain (P < 0.001), we found that HRDD is impaired in patients with type 1 or type 2 diabetes with neuropathic pain. These impairments are unrelated to diabetes type and the presence or severity of neuropathy. In contrast, patients without neuropathic pain (P < 0.05) exhibited enhanced HRDD compared with control subjects. CONCLUSIONS We suggest that loss or impairment of HRDD may help to identify a subpopulation of patients with painful diabetic neuropathy mediated by impaired spinal inhibitory systems who may respond optimally to therapies that target spinal or supraspinal mechanisms. Enhanced RDD in patients without pain may reflect engagement of spinal pain-suppressing mechanisms.
Collapse
Affiliation(s)
- Anne Worthington
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K
| | - Alise Kalteniece
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K
| | - Maryam Ferdousi
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K
| | - Luca D'Onofrio
- Department of Experimental Medicine, Sapienza University, Rome, Italy
| | - Shaishav Dhage
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K
| | - Shazli Azmi
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K.,Diabetes Centre, Manchester University NHS Foundation Trust, Manchester, U.K
| | - Clare Adamson
- Diabetes Centre, Manchester University NHS Foundation Trust, Manchester, U.K
| | - Shaheen Hamdy
- Centre for Gastrointestinal Sciences, Division of Diabetes and Endocrinology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K
| | - Rayaz A Malik
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, U.K.,Weill Cornell Medicine-Qatar, Research Division, Qatar Foundation, Education City
| | - Nigel A Calcutt
- Department of Pathology, University of California, San Diego, La Jolla, CA
| | - Andrew G Marshall
- Division of Neuroscience and Experimental Psychology, Faculty of Medical and Human Sciences, University of Manchester, Manchester, U.K. .,Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, U.K
| |
Collapse
|
13
|
Dallel R. Advances in the understanding and treatment of pain and headache. J Neural Transm (Vienna) 2021; 127:389-392. [PMID: 32172470 DOI: 10.1007/s00702-020-02164-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Radhouane Dallel
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, F-63000, Clermont-Ferrand, France.
| |
Collapse
|
14
|
The role of glutamate transporter-1 in firing activity of locus coeruleus neurons and nociception in rats. Exp Brain Res 2021; 239:1287-1294. [PMID: 33619583 DOI: 10.1007/s00221-021-06065-0] [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: 10/28/2020] [Accepted: 02/13/2021] [Indexed: 10/22/2022]
Abstract
Locus coeruleus (LC) is considered to be the main source of norepinephrine in the central nervous system (CNS) and plays important role in relieving pain in the body. Changes in the activity of synaptic excitatory amino acid transporters (EAATs) would be an applicable way to regulate synaptic transmission in the LC. In the present study, we examined the role of astrocytic glutamate transporter-1 (GLT1) in the firing activity of LC neurons and the sensation of pain in rats. Male Wistar rats were divided into three control (CNT), ceftriaxone (CFT) and dihydrokainic acid (DHK) groups. Animals were given intraperitoneal injections for nine consecutive days after which the electrophysiological and behavioral experiments were performed to determine the single-unit activity of LC neurons and pain sensation. Results of this study revealed that CFT as a well-known up-regulator of GLT1 expression decreases the latency of pain sensation in rats but inhibition of GLT1 activity by DHK showed no significant effects. Furthermore, the results obtained by single-unit recording from LC showed a significant decrease in evoked response in CFT group compared to the CNT group. Therefore, this study suggests that GLT1 might be considered as a potential therapeutic target for pain modulation in the future.
Collapse
|
15
|
Kopruszinski CM, Turnes JM, Swiokla J, Weinstein TJ, Schwedt TJ, Dodick DW, Anderson T, Navratilova E, Porreca F. CGRP monoclonal antibody prevents the loss of diffuse noxious inhibitory controls (DNIC) in a mouse model of post-traumatic headache. Cephalalgia 2021; 41:749-759. [PMID: 33615840 DOI: 10.1177/0333102420981688] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM Determine the role of calcitonin-gene related peptide in promoting post-traumatic headache and dysregulation of central pain modulation induced by mild traumatic brain injury in mice. METHODS Mild traumatic brain injury was induced in lightly anesthetized male C57BL/6J mice by a weight drop onto a closed and unfixed skull, which allowed free head rotation after the impact. We first determined possible alterations in the diffuse noxious inhibitory controls, a measure of net descending pain inhibition called conditioned pain modulation in humans at day 2 following mild traumatic brain injury. Diffuse noxious inhibitory control was assessed as the latency to a thermally induced tail-flick that served as the test stimulus in the presence of right forepaw capsaicin injection that provided the conditioning stimulus. Post-traumatic headache-like behaviors were assessed by the development of cutaneous allodynia in the periorbital and hindpaw regions after mild traumatic brain injury. We then determined if intraperitoneal fremanezumab, an anti-calcitonin-gene related peptide monoclonal antibody or vehicle administered 2 h after sham or mild traumatic brain injury induction could alter cutaneous allodynia or diffuse noxious inhibitory control responses on day 2 post mild traumatic brain injury. RESULTS In naïve and sham mice, capsaicin injection into the forepaw elevated the latency to tail-flick, reflecting the antinociceptive diffuse noxious inhibitory control response. Periorbital and hindpaw cutaneous allodynia, as well as a loss of diffuse noxious inhibitory control, was observed in mice 2 days after mild traumatic brain injury. Systemic treatment with fremanezumab blocked mild traumatic brain injury-induced cutaneous allodynia and prevented the loss of diffuse noxious inhibitory controls in mice subjected to a mild traumatic brain injury. INTERPRETATION Sequestration of calcitonin-gene related peptide in the initial stages following mild traumatic brain injury blocked the acute allodynia that may reflect mild traumatic brain injury-related post-traumatic headache and, additionally, prevented the loss of net descending inhibition within central pain modulation pathways. As loss of conditioned pain modulation has been linked to multiple persistent pain conditions, dysregulation of descending modulatory pathways may contribute to the persistence of post-traumatic headache. Additionally, evaluation of the conditioned pain modulation/diffuse noxious inhibitory controls response may serve as a biomarker of vulnerability for chronic/persistent pain. These findings suggest that early anti-calcitonin-gene related peptide intervention has the potential to be effective both for the treatment of mild traumatic brain injury-induced post-traumatic headache, as well as inhibiting mechanisms that may promote post-traumatic headache persistence.
Collapse
Affiliation(s)
- Caroline M Kopruszinski
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona, USA
| | - Joelle M Turnes
- Department of Pharmacology, Federal University of Parana, Curitiba, Parana, Brazil
| | - Juliana Swiokla
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona, USA
| | - Troy J Weinstein
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona, USA
| | | | | | - Trent Anderson
- Department of Biomedical Sciences, College of Medicine, University of Arizona, Phoenix, AZ, USA
| | - Edita Navratilova
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona, USA
| | - Frank Porreca
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona, USA.,Department of Neurology, Mayo Clinic, Phoenix, AZ, USA
| |
Collapse
|
16
|
Painful Cutaneous Electrical Stimulation vs. Heat Pain as Test Stimuli in Conditioned Pain Modulation. Brain Sci 2020; 10:brainsci10100684. [PMID: 32998204 PMCID: PMC7599732 DOI: 10.3390/brainsci10100684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 09/24/2020] [Accepted: 09/26/2020] [Indexed: 11/30/2022] Open
Abstract
Different paradigms can assess the effect of conditioned pain modulation (CPM). The aim of the present study was to compare heat pain, as an often used test stimulus (TS), to painful cutaneous electrical stimulation (PCES), having the advantage of the additional recording of PCES-related evoked potentials. In 28 healthy subjects we applied heat and PCES at the dominant hand as test stimulus (TS) to compare the CPM-effect elicited by hand immersion into cold water (10 °C) as conditioning stimulus (CS). Subjects rated the pain intensity of TS at baseline, during and 5 min after CS application and additionally of CS, on a numerical rating scale (NRS) (0–100). The ‘early’ (during CS–before CS) and ‘late’ (after CS–before CS) CPM-effects were analyzed. Parallel to the PCES, the related evoked potentials were recorded via Cz to evaluate any changes in PCES-amplitudes. CS reduced significantly the pain intensity of both PCES and heat pain as TS. On a group level, the CPM-effect did not differ significantly between both paradigms. Both early and late CPM-effect based on PCES correlated significantly with the CS pain intensity (r = −0.630 and −0.503, respectively), whereas using heat pain the correlation was not significant. We found a significant reduction of PCES-amplitudes during CS, but this did not correlate with the PCES-induced pain intensity. Correlation with the CS painfulness (r = −0.464) did not achieve the significance level after Bonferroni correction. The extent of the CPM effects was similar in both testing paradigms at group level, despite intraindividual differences. Future studies should further elicit the exact mechanisms explaining the modality of these specific differences.
Collapse
|
17
|
Hilton E, Satia I, Holt K, Woodcock AA, Belcher J, Smith JA. The Effect of Pain Conditioning on Experimentally Evoked Cough: Evidence of Impaired Endogenous Inhibitory Control Mechanisms in Refractory Chronic Cough. Eur Respir J 2020; 56:2001387. [PMID: 32703776 DOI: 10.1183/13993003.01387-2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 06/28/2020] [Indexed: 01/31/2023]
Abstract
The pathophysiology of refractory chronic cough (RCC) is unclear. We hypothesised that endogenous inhibitory control mechanisms, such as those activated by noxiousstimuli inducing pain (conditioned pain modulation (CPM)), may be capable of inhibiting coughing and urge to cough evoked by inhaled capsaicin. Furthermore, these mechanisms may be impaired in patients with RCC.The objective was to investigate the effects of pain on cough and urge to cough (UTC) in healthy volunteers (HV) and RCC. HV and RCC patients underwent a randomised, controlled, 4-way cross-over study comparing the effect of 4 interventions on capsaicin evoked coughing and UTC. The interventions comprised immersing a hand in i) noxious cold-water, ii) warm water, iii) warm water but instructed to voluntarily supress coughing and iv) no intervention. The co-primary outcomes were numbers of evoked coughs and UTC scores.Twenty HV (mean age 50.1(±SD14.2), M:F 10:10) and 20 RCC (age 60.1(±7.9), M:F 9:11) participated. Overall, noxious cold water reduced capsaicin evoked UTC scores and cough numbers compared with warm water (1.6 (95% C.I. 1.3-2.0) versus 2.2 (1.8-2.6) p<0.001; 4.8 coughs (3.7-6.2) versus 7.9 coughs (6.7-9.5) p<0.001, respectively). HV and RCC demonstrated similar reductions in the UTC during noxious cold-water immersion, but noxious cold water and voluntary suppression interventions were less effective in RCC than HV in reducing capsaicin evoked cough (p=0.041).Endogenous inhibitory control mechanisms, specifically those activated by pain, can reduce both coughing and the UTC. Impairment of endogenous inhibitory control mechanisms may contribute to excessive coughing in RCC.
Collapse
Affiliation(s)
- Emma Hilton
- Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Equal contributors
| | - Imran Satia
- Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Department of Medicine, Division of Respirology, McMaster University, Hamilton, Canada
- Equal contributors
| | - Kimberley Holt
- Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Manchester University NHS Foundation Trust, Manchester, UK
| | - Ashley A Woodcock
- Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Manchester University NHS Foundation Trust, Manchester, UK
| | - John Belcher
- Manchester University NHS Foundation Trust, Manchester, UK
| | - Jaclyn A Smith
- Division of Infection, Immunity and Respiratory Medicine, and Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Manchester University NHS Foundation Trust, Manchester, UK
| |
Collapse
|
18
|
Dickenson AH, Patel R. Translational issues in precision medicine in neuropathic pain. CANADIAN JOURNAL OF PAIN-REVUE CANADIENNE DE LA DOULEUR 2020; 4:30-38. [PMID: 32258972 PMCID: PMC7077367 DOI: 10.1080/24740527.2020.1720502] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/14/2020] [Accepted: 01/21/2020] [Indexed: 02/08/2023]
Abstract
Neuropathic pain remains poorly treated, with most new drugs falling through the translational gap. The traditional model of bench-to-bedside research has relied on identifying new mechanisms/targets in animal models and then developing clinical applications. Several have advocated bridging the translational gap by beginning with clinical observations and back-translating to animal models for further investigation of mechanisms. There is good evidence that phenotyping of patients through quantitative sensory testing can lead to improved treatment selection and hence improved patient outcomes. This practice has been widely adopted in clinical investigations, but its application in preclinical research is not mainstream. In this review, we retrospectively examine our historical rodent data sets with the aim of reconsidering drug effects on sensory neuronal endpoints, their alignment with clinical observations, and how these might guide future clinical studies.
Collapse
Affiliation(s)
- Anthony H Dickenson
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Ryan Patel
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| |
Collapse
|