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Allen D, Hanumantharao SN, McDonell R, Irvine KA, Sahbaie P, Clark D, Blum P. Preclinical characterization of the efficacy and safety of biologic N-001 as a novel pain analgesic for post-operative acute pain treatment. Sci Rep 2023; 13:11778. [PMID: 37479740 PMCID: PMC10362049 DOI: 10.1038/s41598-023-38618-4] [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: 03/23/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023] Open
Abstract
Inhibition of actin remodeling in nerves modulates action potential propagation and therefore could be used to treat acute pain. N-001 is a novel protein analgesic engineered from several C. Botulinum toxins. N-001 targets sensory neurons through ganglioside GT1b binding and ADP-ribosylates G-actin reducing actin remodeling. The activity and efficacy of N-001 was evaluated previously in vitro and in a mouse inflammatory pain model. To assess the relevance of N-001 for treatment of acute post-surgical pain, the current study evaluated the efficacy of N-001 in a mouse hind-paw incision model by peri-incisional and popliteal nerve block administration combined with mechanical testing. N-001 provided relief of pain-like behavior over 3 days and 2 days longer than the conventional long-acting anesthetic bupivacaine. Preclinical safety studies of N-001 indicated the drug produced no toxic or adverse immunological reactions over multiple doses in mice. These results combined with past targeting results encourage further investigation of N-001 as an analgesic for post-operative pain management with the potential to function as a differential nociceptor-specific nerve block.
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Affiliation(s)
- Derek Allen
- Neurocarrus Inc, Monterey, CA, USA
- Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, CA, USA
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Rylie McDonell
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Peyman Sahbaie
- Stanford University School of Medicine, Stanford, CA, USA
| | - David Clark
- Stanford University School of Medicine, Stanford, CA, USA
- VA Palo Alto Health Care, Palo Alto, CA, USA
| | - Paul Blum
- Neurocarrus Inc, Monterey, CA, USA.
- Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, CA, USA.
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
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2
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Oz M, Lorke DE, Howarth FC. Transient receptor potential vanilloid 1 (TRPV1)-independent actions of capsaicin on cellular excitability and ion transport. Med Res Rev 2023. [PMID: 36916676 DOI: 10.1002/med.21945] [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: 06/14/2022] [Revised: 01/17/2023] [Accepted: 02/26/2023] [Indexed: 03/15/2023]
Abstract
Capsaicin is a naturally occurring alkaloid derived from chili pepper that is responsible for its hot pungent taste. Capsaicin is known to exert multiple pharmacological actions, including analgesia, anticancer, anti-inflammatory, antiobesity, and antioxidant effects. The transient receptor potential vanilloid subfamily member 1 (TRPV1) is the main receptor mediating the majority of the capsaicin effects. However, numerous studies suggest that the TRPV1 receptor is not the only target for capsaicin. An increasing number of studies indicates that capsaicin, at low to mid µM ranges, not only indirectly through TRPV1-mediated Ca2+ increases, but also directly modulates the functions of voltage-gated Na+ , K+ , and Ca2+ channels, as well as ligand-gated ion channels and other ion transporters and enzymes involved in cellular excitability. These TRPV1-independent effects are mediated by alterations of the biophysical properties of the lipid membrane and subsequent modulation of the functional properties of ion channels and by direct binding of capsaicin to the channels. The present study, for the first time, systematically categorizes this diverse range of non-TRPV1 targets and discusses cellular and molecular mechanisms mediating TRPV1-independent effects of capsaicin in excitable, as well as nonexcitable cells.
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Affiliation(s)
- Murat Oz
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
| | - Dietrich E Lorke
- Department of Anatomy and Cellular Biology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.,Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Frank C Howarth
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
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3
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Messina DN, Peralta ED, Seltzer AM, Patterson SI, Acosta CG. Age-dependent and modality-specific changes in the phenotypic markers Nav1.8, ASIC3, P2X3 and TRPM8 in male rat primary sensory neurons during healthy aging. Biogerontology 2023; 24:111-136. [PMID: 36478541 DOI: 10.1007/s10522-022-10000-3] [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: 07/26/2022] [Accepted: 11/08/2022] [Indexed: 12/12/2022]
Abstract
The effects during healthy aging of the tetrodotoxin-resistant voltage-gated sodium channel 1.8 (Nav1.8), the acid-sensing ion channel-3 (ASIC3), the purinergic-receptor 2X3 (P2X3) and transient receptor potential of melastatin-8 (TRPM8) on responses to non-noxious stimuli are poorly understood. These effects will influence the transferability to geriatric subjects of findings obtained using young animals. To evaluate the involvement of these functional markers in mechanical and cold sensitivity to non-noxious stimuli and their underlying mechanisms, we used a combination of immunohistochemistry and quantitation of immunostaining in sub-populations of neurons of the dorsal root ganglia (DRG), behavioral tests, pharmacological interventions and Western-blot in healthy male Wistar rats from 3 to 24 months of age. We found significantly decreased sensitivity to mechanical and cold stimuli in geriatric rats. These behavioural alterations occurred simultaneously with differing changes in the expression of Nav1.8, ASIC3, P2X3 and TRPM8 in the DRG at different ages. Using pharmacological blockade in vivo we demonstrated the involvement of ASIC3 and P2X3 in normal mechanosensation and of Nav1.8 and ASIC3 in cold sensitivity. Geriatric rats also exhibited reductions in the number of A-like large neurons and in the proportion of peptidergic to non-peptidergic neurons. The changes in normal sensory physiology in geriatric rats we report here strongly support the inclusion of aged rodents as an important group in the design of pre-clinical studies evaluating pain treatments.
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Affiliation(s)
- Diego N Messina
- Laboratorio de Estudios Neurobiológicos (LABENE), Facultad de Ciencias Médicas, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Universidad Nacional de Cuyo, 5500, Mendoza, Argentina
| | - Emanuel D Peralta
- Laboratorio de Estudios Neurobiológicos (LABENE), Facultad de Ciencias Médicas, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Universidad Nacional de Cuyo, 5500, Mendoza, Argentina
| | - Alicia M Seltzer
- Laboratorio de Estudios Neurobiológicos (LABENE), Facultad de Ciencias Médicas, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Universidad Nacional de Cuyo, 5500, Mendoza, Argentina
| | - Sean I Patterson
- Instituto de Fisiología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.,Instituto de Histología y Embriología - CONICET, Universidad Nacional de Cuyo, 5500, Mendoza, Argentina
| | - Cristian G Acosta
- Laboratorio de Estudios Neurobiológicos (LABENE), Facultad de Ciencias Médicas, Instituto de Histología y Embriología de Mendoza (IHEM-CONICET), Universidad Nacional de Cuyo, 5500, Mendoza, Argentina. .,Histology Laboratory 107, IHEM-Faculty of Medical Sciences, National University of Cuyo, Av. del Libertador 80, 5500, Mendoza, Argentina.
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A subset of spinal dorsal horn interneurons crucial for gating touch-evoked pain-like behavior. Proc Natl Acad Sci U S A 2021; 118:2021220118. [PMID: 33431693 DOI: 10.1073/pnas.2021220118] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A cardinal, intractable symptom of neuropathic pain is mechanical allodynia, pain caused by innocuous stimuli via low-threshold mechanoreceptors such as Aβ fibers. However, the mechanism by which Aβ fiber-derived signals are converted to pain remains incompletely understood. Here we identify a subset of inhibitory interneurons in the spinal dorsal horn (SDH) operated by adeno-associated viral vectors incorporating a neuropeptide Y promoter (AAV-NpyP+) and show that specific ablation or silencing of AAV-NpyP+ SDH interneurons converted touch-sensing Aβ fiber-derived signals to morphine-resistant pain-like behavioral responses. AAV-NpyP+ neurons received excitatory inputs from Aβ fibers and transmitted inhibitory GABA signals to lamina I neurons projecting to the brain. In a model of neuropathic pain developed by peripheral nerve injury, AAV-NpyP+ neurons exhibited deeper resting membrane potentials, and their excitation by Aβ fibers was impaired. Conversely, chemogenetic activation of AAV-NpyP+ neurons in nerve-injured rats reversed Aβ fiber-derived neuropathic pain-like behavior that was shown to be morphine-resistant and reduced pathological neuronal activation of superficial SDH including lamina I. These findings suggest that identified inhibitory SDH interneurons that act as a critical brake on conversion of touch-sensing Aβ fiber signals into pain-like behavioral responses. Thus, enhancing activity of these neurons may offer a novel strategy for treating neuropathic allodynia.
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5
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Sultana A, Singla RK, He X, Sun Y, Alam MS, Shen B. Topical Capsaicin for the Treatment of Neuropathic Pain. Curr Drug Metab 2021; 22:198-207. [PMID: 33198614 DOI: 10.2174/1389200221999201116143701] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/05/2020] [Accepted: 08/09/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND Neuropathic pain (NP) is an egregious problem worldwide. Due to the side-effects of oral drugs, drugs delivered directly to the affected area of pain are preferred. OBJECTIVE Capsaicin, a chemical compound isolated from chili peppers, is used as an analgesic in topical ointments and dermal patches to alleviate pain. Objective of the study is to review the application and functionality of topical capsaicin in treatment of neuropathic pain. DATA SOURCES To systematically review capsaicin's functions on NP, we retrieved articles from the PubMed database published in the last ten years. STUDY ELIGIBILITY CRITERIA The inclusion criteria were capsaicin and the use of capsaicin for the treatment of NP; on the other hand, articles were excluded according to the mentioned criteria such as abstracts, articles written in any language other than English, incomplete articles, and conference papers. PARTICIPANTS AND INTERVENTIONS Out of 265 articles, 108 articles were selected after filtering through the inclusion and exclusion criteria. The data and knowledge currently existing for capsaicin treatment in NP are summarized. RESULTS This review indicates that capsaicin effectively improves NP treatment without affecting the motor and large nerve fibres involved in sensory function. Transient receptor potential channel vanilloid type 1 (TRPV1) is the capsaicin receptor expressed in central and peripheral terminals of a sensitive primary nerve cell. Conclusions and implications of key findings: Topical capsaicin has a sensible safety profile and is effective in reducing NP. Therefore, studies over the last decade suggest that capsaicin might be a potential drug for NP treatment.
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Affiliation(s)
- Adiba Sultana
- Center for Systems Biology, Soochow University, Suzhou, 215006, China
| | - Rajeev K Singla
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xuefei He
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Yan Sun
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, 610041, Sichuan, China
| | - Md Shahin Alam
- Center for Systems Biology, Soochow University, Suzhou, 215006, China
| | - Bairong Shen
- Center for Systems Biology, Soochow University, Suzhou, 215006, China
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Wang Q, Zhang Y, Liu J, Zhang W. Quaternary Lidocaine Derivatives: Past, Present, and Future. Drug Des Devel Ther 2021; 15:195-207. [PMID: 33469271 PMCID: PMC7813469 DOI: 10.2147/dddt.s291229] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 12/25/2020] [Indexed: 02/05/2023] Open
Abstract
Local anesthetics have the advantage of complete analgesia with fewer side effects compared to systemic analgesics. However, their clinical use is limited due to their short duration of action. Thus, local anesthetics with fast onset, long duration of action, selective nociceptive block, and low local and systemic toxicity are highly desirable. In the past electrophysiological studies, quaternary lidocaine derivatives (QLDs) showed these characteristics. Here, we review electrophysiological properties of QLDs and their pharmacodynamic characteristics to shed light on potential problems.
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Affiliation(s)
- Qi Wang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Yujun Zhang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Jin Liu
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Wensheng Zhang
- Department of Anesthesiology, Laboratory of Anesthesia and Critical Care Medicine, Translational Neuroscience Centre, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu, People's Republic of China
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7
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Hwang SM, Lee K, Im ST, Go EJ, Kim YH, Park CK. Co-Application of Eugenol and QX-314 Elicits the Prolonged Blockade of Voltage-Gated Sodium Channels in Nociceptive Trigeminal Ganglion Neurons. Biomolecules 2020; 10:E1513. [PMID: 33167484 PMCID: PMC7694476 DOI: 10.3390/biom10111513] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/31/2020] [Accepted: 11/02/2020] [Indexed: 12/11/2022] Open
Abstract
Local anesthetics (LAs) can completely block nociception by inhibiting voltage-gated sodium channels (VGSCs), and thus, blocking action potentials (APs) within sensory neurons. As one of the several LAs, eugenol is used for dental pain treatment. It reportedly features multiple functions in regulating diverse ion channels. This study aimed to investigate the long-lasting analgesic effect of eugenol alone, as well as that of the combination of eugenol as a noxious-heat-sensitive transient receptor potential vanilloid 1 (TRPV1) channel agonist and a permanently charged sodium channel blocker (QX-314), on neuronal excitability in trigeminal ganglion (TG) neurons. Eugenol alone increased inward current in a dose-dependent manner in capsaicin-sensitive TG neurons. Eugenol also inhibited the VGSC current and AP. These effects were reversed through wash-out. The combination of eugenol and QX-314 was evaluated in the same manner. The combination completely inhibited the VGSC current and AP. However, these effects were not reversed and were continuously blocked even after wash-out. Taken together, our results suggest that, in contrast to the effect of eugenol alone, the combination of eugenol and QX-314 irreversibly and selectively blocked VGSCs in TG neurons expressing TRPV1.
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Affiliation(s)
- Sung-Min Hwang
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon 21999, Korea; (S.-M.H.); (K.L.); (S.-T.I.); (E.J.G.)
| | - Kihwan Lee
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon 21999, Korea; (S.-M.H.); (K.L.); (S.-T.I.); (E.J.G.)
| | - Sang-Taek Im
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon 21999, Korea; (S.-M.H.); (K.L.); (S.-T.I.); (E.J.G.)
- Fight against Angiogenesis-Related Blindness (FARB) Laboratory, Seoul National University Hospital, Seoul 03082, Korea
| | - Eun Jin Go
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon 21999, Korea; (S.-M.H.); (K.L.); (S.-T.I.); (E.J.G.)
| | - Yong Ho Kim
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon 21999, Korea; (S.-M.H.); (K.L.); (S.-T.I.); (E.J.G.)
| | - Chul-Kyu Park
- Gachon Pain Center and Department of Physiology, Gachon University College of Medicine, Incheon 21999, Korea; (S.-M.H.); (K.L.); (S.-T.I.); (E.J.G.)
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8
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Dai YE, Liu SX, Ye L, Zuo YX. Clinical Efficacy of Ultrasound-Mediated Transdermal Lidocaine and Capsaicin Delivery for the Treatment of Allodynia Caused by Herpes Zoster. PAIN MEDICINE 2020; 21:3739-3746. [PMID: 32524145 DOI: 10.1093/pm/pnaa137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE To investigate the efficacy of ultrasound-mediated drug delivery for allodynia caused by herpes zoster. DESIGN Unblinded randomized controlled study with two treatment groups and an additional control group. SUBJECTS Patients hospitalized with allodynia caused by herpes zoster were enrolled. METHODS Patients were randomly assigned to three groups: ultrasound-mediated transdermal drug delivery (group U), lidocaine intradermal injection (group I), or control group (group C). The primary outcome was pain intensity associated with allodynia, assessed with the visual analog scale (VAS) while brushing the skin with clothing after treatment stimulated allodynia. The secondary outcomes included an emotional functioning score (ES), average gabapentin consumption, and incidence of adverse events of each group. RESULTS Sixty patients were enrolled in the study, but two of them failed to complete the treatment process. Therefore, 58 patients were included in the final analysis. All groups had lower VAS and ES scores after treatment compared with baseline. The VAS scores in groups U and I decreased significantly more than in group C (P < 0.05). Mean VAS scores in group U on days 1, 2, and 3 were lower than in group C (P < 0.01). ES was significantly lower in group U compared with groups I and C after treatment (P < 0.001). Average gabapentin consumption and incidence of adverse events in group C were higher than in the other two groups. CONCLUSIONS In this study of treatment of allodynia caused by herpetic zoster, ultrasound-mediated lidocaine and capsaicin delivery provided better pain relief and improved emotional functioning compared with intradermal blockade with local anesthetics.
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Affiliation(s)
- Yue-E Dai
- Department of Anesthesiology, West China Hospital, Sichuan University & The Research Units of West China (2018RU012), Chinese Academy of Medical Sciences, Chengdu, Sichuan, People's Republic of China.,Department of Anesthesiology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People's Republic of China
| | - Shao-Xing Liu
- Department of Anesthesiology, Chengdu Second People's Hospital, Chengdu, Sichuan, People's Republic of China
| | - Ling Ye
- Department of Pain Management, West China Hospital, Sichuan University & The Research Units of West China (2018RU012), Chinese Academy of Medical Sciences, Chengdu, Sichuan, People's Republic of China
| | - Yun-Xia Zuo
- Department of Anesthesiology, West China Hospital, Sichuan University & The Research Units of West China (2018RU012), Chinese Academy of Medical Sciences, Chengdu, Sichuan, People's Republic of China
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Zakir HM, Masuda Y, Kitagawa J. A novel approach for detection of functional expression of TRPV1 channels on regenerated neurons following nerve injury. J Oral Sci 2020; 62:136-139. [PMID: 32074545 DOI: 10.2334/josnusd.19-0356] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is a polymodal receptor channel, which plays an important role in pain transduction. It is important to understand the functional expression of this channel under neuropathic pain (NP) conditions. A novel method was used to investigate the dynamics of functional expression of this channel on regenerated neurons under NP conditions following trigeminal nerve injury using a combination of a permanently charged sodium channel blocker (QX-314) and a TRPV1 agonist (capsaicin; QX-CAP). The combination was originally introduced as a local anesthetic. Synchronization between the local anesthetic effect of QX-CAP and TRPV1 expression on regenerated neurons was observed following the nerve injury. QX-CAP had no local anesthetic effect under NP conditions 2 weeks after the injury when TRPV1 expression on regenerated neurons was low. However, this combination was effective under NP conditions 3 and 4 weeks following injury when TRPV1 expression in regenerated neurons was moderate to high. The current review, discusses the potential of QX-314 as a local anesthetic and a novel approach of using QX-CAP to reveal the dynamics of functional expression of TRPV1 on regenerated neurons following trigeminal nerve injury.
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Affiliation(s)
- Hossain M Zakir
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University
| | - Yuji Masuda
- Institute for Oral Science, Matsumoto Dental University
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University
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11
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Optogenetic Activation of Non-Nociceptive Aβ Fibers Induces Neuropathic Pain-Like Sensory and Emotional Behaviors after Nerve Injury in Rats. eNeuro 2018; 5:eN-NWR-0450-17. [PMID: 29468190 PMCID: PMC5819669 DOI: 10.1523/eneuro.0450-17.2018] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 01/25/2018] [Indexed: 01/16/2023] Open
Abstract
Neuropathic pain is caused by peripheral nerve injury (PNI). One hallmark symptom is allodynia (pain caused by normally innocuous stimuli), but its mechanistic underpinning remains elusive. Notably, whether selective stimulation of non-nociceptive primary afferent Aβ fibers indeed evokes neuropathic pain-like sensory and emotional behaviors after PNI is unknown, because of the lack of tools to manipulate Aβ fiber function in awake, freely moving animals. In this study, we used a transgenic rat line that enables stimulation of non-nociceptive Aβ fibers by a light-activated channel (channelrhodopsin-2; ChR2). We found that illuminating light to the plantar skin of these rats with PNI elicited pain-like withdrawal behaviors that were resistant to morphine. Light illumination to the skin of PNI rats increased the number of spinal dorsal horn (SDH) Lamina I neurons positive to activity markers (c-Fos and phosphorylated extracellular signal-regulated protein kinase; pERK). Whole-cell recording revealed that optogenetic Aβ fiber stimulation after PNI caused excitation of Lamina I neurons, which were normally silent by this stimulation. Moreover, illuminating the hindpaw of PNI rats resulted in activation of central amygdaloid neurons and produced an aversion to illumination. Thus, these findings provide the first evidence that optogenetic activation of primary afferent Aβ fibers in PNI rats produces excitation of Lamina I neurons and neuropathic pain-like behaviors that were resistant to morphine treatment. This approach may provide a new path for investigating circuits and behaviors of Aβ fiber-mediated neuropathic allodynia with sensory and emotional aspects after PNI and for discovering novel drugs to treat neuropathic pain.
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12
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Liu L, Yin Y, Li F, Malhotra C, Cheng J. Flow cytometry analysis of inflammatory cells isolated from the sciatic nerve and DRG after chronic constriction injury in mice. J Neurosci Methods 2017; 284:47-56. [PMID: 28445708 DOI: 10.1016/j.jneumeth.2017.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 02/05/2023]
Abstract
BACKGROUND Cellular responses to nerve injury play a central role in the pathogenesis of neuropathic pain. However, the analysis of site specific cellular responses to nerve injury and neuropathic pain is limited to immunohistochemistry staining with numerous limitations. NEW METHODS We proposed to apply flow cytometry to overcome some of the limitations and developed two protocols for isolation of cells from small specimens of the sciatic nerve and dorsal root ganglion (DRG) in mice. RESULTS AND COMPARASION WITH EXISTING: methods We found that both the non-enzymatic and enzymatic approaches were highly effective in harvesting a sufficient number of cells for flow cytometry analysis in normal and pathological conditions. The total number of cells in the injury site of the sciatic and its DRGs increased significantly 14days after chronic constriction injury (CCI) of the sciatic nerve, compared to sham surgery control or the contralateral control. The enzymatic approach yielded a significantly higher total number of cells and CD45 negative cells, suggesting that this approach allows for harvest of more resident cells, compared to the non-enzymatic method. The percentage of CD45+/CD11b+ cells was significantly increased in the sciatic nerve but not in the DRG. These results were consistent with both protocols. CONCLUSIONS We thus offer two simple and effective protocols that allow for application of flow cytometry to the investigation of cellular and molecular mechanisms of neuropathic pain.
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Affiliation(s)
- Liping Liu
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, Euclid Avenue, Cleveland, OH 44195, USA
| | - Yan Yin
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, Euclid Avenue, Cleveland, OH 44195, USA; Department of Anesthesiology, West China Hospital of Sichuan University, 610041, China
| | - Fei Li
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, Euclid Avenue, Cleveland, OH 44195, USA
| | - Charvi Malhotra
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, Euclid Avenue, Cleveland, OH 44195, USA
| | - Jianguo Cheng
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, Euclid Avenue, Cleveland, OH 44195, USA.
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Stueber T, Eberhardt MJ, Hadamitzky C, Jangra A, Schenk S, Dick F, Stoetzer C, Kistner K, Reeh PW, Binshtok AM, Leffler A. Quaternary Lidocaine Derivative QX-314 Activates and Permeates Human TRPV1 and TRPA1 to Produce Inhibition of Sodium Channels and Cytotoxicity. Anesthesiology 2016; 124:1153-65. [PMID: 26859646 DOI: 10.1097/aln.0000000000001050] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND The relatively membrane-impermeable lidocaine derivative QX-314 has been reported to permeate the ion channels transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential cation channel, subfamily A, member 1 (TRPA1) to induce a selective inhibition of sensory neurons. This approach is effective in rodents, but it also seems to be associated with neurotoxicity. The authors examined whether the human isoforms of TRPV1 and TRPA1 allow intracellular entry of QX-314 to mediate sodium channel inhibition and cytotoxicity. METHODS Human embryonic kidney 293 (HEK-293) cells expressing wild-type or mutant human (h) TRPV1 or TRPA1 constructs as well as the sodium channel Nav1.7 were investigated by means of patch clamp and ratiometric calcium imaging. Cytotoxicity was examined by flow cytometry. RESULTS Activation of hTRPA1 by carvacrol and hTRPV1 by capsaicin produced a QX-314-independent reduction of sodium current amplitudes. However, permeation of QX-314 through hTRPV1 or hTRPA1 was evident by a concentration-dependent, use-dependent inhibition of Nav1.7 activated at 10 Hz. Five and 30 mM QX-314 activated hTRPV1 via mechanisms involving the intracellular vanilloid-binding domain and hTRPA1 via unknown mechanisms independent of intracellular cysteins. Expression of hTRPV1, but not hTRPA1, was associated with a QX-314-induced cytotoxicity (viable cells 48 ± 5% after 30 mM QX-314) that was ameliorated by the TRPV1 antagonist 4-(3-chloro-2-pyridinyl)-N-[4-(1,1-dimethylethyl)phenyl]-1-piperazinecarboxamide (viable cells 81 ± 5%). CONCLUSIONS The study data demonstrate that QX-314 directly activates and permeates the human isoforms of TRPV1 and TRPA1 to induce inhibition of sodium channels, but also a TRPV1-dependent cytotoxicity. These results warrant further validation of this approach in more intact preparations and may be valuable for the development of this concept into clinical practice.
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Affiliation(s)
- Thomas Stueber
- From the Department of Anaesthesiology and Intensive Care Medicine, Hannover Medical School, Hannover, Germany (T.S., M.J.E., C.H., A.J., S.S., F.D., C.S., A.L.); Department of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (K.K., P.W.R.); and Department of Medical Neurobiology, Institute for Medical Research Israel-Canada, The Hebrew University Faculty of Medicine, and The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University, Jerusalem, Israel (A.M.B.)
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Hua Z, Liu L, Shen J, Cheng K, Liu A, Yang J, Wang L, Qu T, Yang H, Li Y, Wu H, Narouze J, Yin Y, Cheng J. Mesenchymal Stem Cells Reversed Morphine Tolerance and Opioid-induced Hyperalgesia. Sci Rep 2016; 6:32096. [PMID: 27554341 PMCID: PMC4995471 DOI: 10.1038/srep32096] [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: 02/19/2016] [Accepted: 08/02/2016] [Indexed: 01/27/2023] Open
Abstract
More than 240 million opioid prescriptions are dispensed annually to treat pain in the US. The use of opioids is commonly associated with opioid tolerance (OT) and opioid-induced hyperalgesia (OIH), which limit efficacy and compromise safety. The dearth of effective way to prevent or treat OT and OIH is a major medical challenge. We hypothesized that mesenchymal stem cells (MSCs) attenuate OT and OIH in rats and mice based on the understanding that MSCs possess remarkable anti-inflammatory properties and that both OT and chronic pain are associated with neuroinflammation in the spinal cord. We found that the development of OT and OIH was effectively prevented by either intravenous or intrathecal MSC transplantation (MSC-TP), which was performed before morphine treatment. Remarkably, established OT and OIH were significantly reversed by either intravenous or intrathecal MSCs when cells were transplanted after repeated morphine injections. The animals did not show any abnormality in vital organs or functions. Immunohistochemistry revealed that the treatments significantly reduced activation level of microglia and astrocytes in the spinal cord. We have thus demonstrated that MSC-TP promises to be a potentially safe and effective way to prevent and reverse two of the major problems of opioid therapy.
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Affiliation(s)
- Zhen Hua
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA.,Department of Anesthesiology, Beijing Hospital, No. 1 Dahua Road, Beijing 100730, China
| | - LiPing Liu
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Jun Shen
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Kathleen Cheng
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Aijun Liu
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Jing Yang
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Lina Wang
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Tingyu Qu
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - HongNa Yang
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Yan Li
- Psychiatric Institute, Department of Psychiatry, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Haiyan Wu
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - John Narouze
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Yan Yin
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
| | - Jianguo Cheng
- Departments of Pain Management and Neurosciences, Lerner Research Institute and Anaesthesiology Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195, USA
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Fernandes ES, Cerqueira ARA, Soares AG, Costa SKP. Capsaicin and Its Role in Chronic Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 929:91-125. [PMID: 27771922 DOI: 10.1007/978-3-319-41342-6_5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A significant number of experimental and clinical studies published in peer-reviewed journals have demonstrated promising pharmacological properties of capsaicin in relieving signs and symptoms of non-communicable diseases (chronic diseases). This chapter provides an overview made from basic and clinical research studies of the potential therapeutic effects of capsaicin, loaded in different application forms, such as solution and cream, on chronic diseases (e.g. arthritis, chronic pain, functional gastrointestinal disorders and cancer). In addition to the anti-inflammatory and analgesic properties of capsaicin largely recognized via, mainly, interaction with the TRPV1, the effects of capsaicin on different cell signalling pathways will be further discussed here. The analgesic, anti-inflammatory or apoptotic effects of capsaicin show promising results in arthritis, neuropathic pain, gastrointestinal disorders or cancer, since evidence demonstrates that the oral or local application of capsaicin reduce inflammation and pain in rheumatoid arthritis, promotes gastric protection against ulcer and induces apoptosis of the tumour cells. Sadly, these results have been paralleled by conflicting studies, which indicate that high concentrations of capsaicin are likely to evoke deleterious effects, thus suggesting that capsaicin activates different pathways at different concentrations in both human and rodent tissues. Thus, to establish effective capsaicin doses for chronic conditions, which can be benefited from capsaicin therapeutic effects, is a real challenge that must be pursued.
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Affiliation(s)
- E S Fernandes
- Programa de Pós-Graduação, Universidade Ceuma, São Luís-MA, Brazil.,Vascular Biology Section, Cardiovascular Division, King's College London, London, UK
| | - A R A Cerqueira
- Department of Pharmacology, Institute of Biomedical Sciences (ICB), University of São Paulo (USP), Av. Prof. Lineu Prestes, 1524 - Room 326, Butantan, São Paulo, 05508-900, Sao Paulo, Brazil
| | - A G Soares
- Department of Pharmacology, Institute of Biomedical Sciences (ICB), University of São Paulo (USP), Av. Prof. Lineu Prestes, 1524 - Room 326, Butantan, São Paulo, 05508-900, Sao Paulo, Brazil
| | - Soraia K P Costa
- Department of Pharmacology, Institute of Biomedical Sciences (ICB), University of São Paulo (USP), Av. Prof. Lineu Prestes, 1524 - Room 326, Butantan, São Paulo, 05508-900, Sao Paulo, Brazil.
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Safrany-Fark A, Petrovszki Z, Kekesi G, Liszli P, Benedek G, Keresztes C, Horvath G. In vivo potency of different ligands on voltage-gated sodium channels. Eur J Pharmacol 2015; 762:158-64. [PMID: 26033207 DOI: 10.1016/j.ejphar.2015.05.053] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 05/19/2015] [Accepted: 05/20/2015] [Indexed: 12/24/2022]
Abstract
The Ranvier nodes of thick myelinated nerve fibers contain almost exclusively voltage-gated sodium channels (Navs), while the unmyelinated fibers have several receptors (e.g., cannabinoid, transient receptor potential vanilloid receptor 1), too. Therefore, a nerve which contains only motor fibers can be an appropriate in vivo model for selective influence of Navs. The goals were to evaluate the potency of local anesthetic drugs on such a nerve in vivo; furthermore, to investigate the effects of ligands with different structures (arachidonic acid, anandamide, capsaicin and nisoxetine) that were proved to inhibit Navs in vitro with antinociceptive properties. The marginal mandibular branch of the facial nerve was explored in anesthetized Wistar rats; after its stimulation, the electrical activity of the vibrissae muscles was registered following the perineural injection of different drugs. Lidocaine, bupivacaine and ropivacaine evoked dose-dependent decrease in electromyographic activity, i.e., lidocaine had lower potency than bupivacaine or ropivacaine. QX-314 did not cause any effect by itself, but its co-application with lidocaine produced a prolonged inhibition. Nisoxetine had a very low potency. While anandamide and capsaicin in high doses caused about 50% decrease in the amplitude of action potential, arachidonic acid did not influence the responses. We proved that the classical local anesthetics have high potency on motor nerves, suggesting that this method might be a reliable model for selective targeting of Navs in vivo circumstances. It is proposed that the effects of these endogenous lipids and capsaicin on sensory fibers are not primarily mediated by Navs.
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Affiliation(s)
- Arpad Safrany-Fark
- Department of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, University of Szeged, Tisza L. krt. 64, H-6720 Szeged, Hungary.
| | - Zita Petrovszki
- Institute of Physical Education and Sport Science, Juhász Gyula Faculty of Education, University of Szeged, Hattyas sor 10, H-6725 Szeged, Hungary.
| | - Gabriella Kekesi
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
| | - Peter Liszli
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
| | - Gyorgy Benedek
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
| | - Csilla Keresztes
- Department of Medical Communication and Translation, Faculty of Medicine, University of Szeged, Szentháromság u. 5, H-6720 Szeged, Hungary.
| | - Gyongyi Horvath
- Department of Physiology, Faculty of Medicine, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary.
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Rogoz K, Stjärne L, Kullander K, Lagerström MC. VGLUT2 controls heat and punctuate hyperalgesia associated with nerve injury via TRPV1-Cre primary afferents. PLoS One 2015; 10:e0116568. [PMID: 25615623 PMCID: PMC4304805 DOI: 10.1371/journal.pone.0116568] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 12/11/2014] [Indexed: 12/04/2022] Open
Abstract
Nerve injury induces a state of prolonged thermal and mechanical hypersensitivity in the innervated area, causing distress in affected individuals. Nerve injury-induced hypersensitivity is partially due to increased activity and thereby sustained release of neurotransmitters from the injured fibers. Glutamate, a prominent neurotransmitter in primary afferents, plays a major role in development of hypersensitivity. Glutamate is packed in vesicles by vesicular glutamate transporters (VGLUTs) to enable controlled release upon depolarization. While a role for peripheral VGLUTs in nerve injury-induced pain is established, their contribution in specific peripheral neuronal populations is unresolved. We investigated the role of VGLUT2, expressed by transient receptor potential vanilloid (TRPV1) fibers, in nerve injury-induced hypersensitivity. Our data shows that removal of Vglut2 from Trpv1-Cre neurons using transgenic mice abolished both heat and punctuate hyperalgesia associated with nerve injury. In contrast, the development of cold hypersensitivity after nerve injury was unaltered. Here, we show that, VGLUT2-mediated glutamatergic transmission from Trpv1-Cre neurons selectively mediates heat and mechanical hypersensitivity associated with nerve injury. Our data clarifies the role of the Trpv1-Cre population and the dependence of VGLUT2-mediated glutamatergic transmission in nerve injury-induced hyperalgesia.
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Affiliation(s)
- Katarzyna Rogoz
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Ludvig Stjärne
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Klas Kullander
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
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Hofmann ME, Largent-Milnes TM, Fawley JA, Andresen MC. External QX-314 inhibits evoked cranial primary afferent synaptic transmission independent of TRPV1. J Neurophysiol 2014; 112:2697-706. [PMID: 25185814 DOI: 10.1152/jn.00316.2014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The cell-impermeant lidocaine derivative QX-314 blocks sodium channels via intracellular mechanisms. In somatosensory nociceptive neurons, open transient receptor potential vanilloid type 1 (TRPV1) receptors provide a transmembrane passageway for QX-314 to produce long-lasting analgesia. Many cranial primary afferents express TRPV1 at synapses on neurons in the nucleus of the solitary tract and caudal trigeminal nucleus (Vc). Here, we investigated whether QX-314 interrupts neurotransmission from primary afferents in rat brain-stem slices. Shocks to the solitary tract (ST) activated highly synchronous evoked excitatory postsynaptic currents (ST-EPSCs). Application of 300 μM QX-314 increased the ST-EPSC latency from TRPV1+ ST afferents, but, surprisingly, it had similar actions at TRPV1- ST afferents. Continued exposure to QX-314 blocked evoked ST-EPSCs at both afferent types. Neither the time to onset of latency changes nor the time to ST-EPSC failure differed between responses for TRPV1+ and TRPV1- inputs. Likewise, the TRPV1 antagonist capsazepine failed to prevent the actions of QX-314. Whereas QX-314 blocked ST-evoked release, the frequency and amplitude of spontaneous EPSCs remained unaltered. In neurons exposed to QX-314, intracellular current injection evoked action potentials suggesting a presynaptic site of action. QX-314 acted similarly at Vc neurons to increase latency and block EPSCs evoked from trigeminal tract afferents. Our results demonstrate that QX-314 blocked nerve conduction in cranial primary afferents without interrupting the glutamate release mechanism or generation of postsynaptic action potentials. The TRPV1 independence suggests that QX-314 either acted extracellularly or more likely entered these axons through an undetermined pathway common to all cranial primary afferents.
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Affiliation(s)
- Mackenzie E Hofmann
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon
| | - Tally M Largent-Milnes
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon
| | - Jessica A Fawley
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon
| | - Michael C Andresen
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon
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Nociceptor-selective peripheral nerve block induces delayed mechanical hypersensitivity and neurotoxicity in rats. Anesthesiology 2014; 120:976-86. [PMID: 24296762 DOI: 10.1097/aln.0000000000000088] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Long-lasting, sensory-specific peripheral nerve blockade would advance perioperative analgesia. Perineural injection of a combination of transient receptor potential vanilloid 1 channel agonists and lidocaine or its hydrophilic derivative, QX-314, produces prolonged sensory or nociceptor-selective nerve block in rodents. In this study, the authors tested the efficacy of these combinations in peripheral nerve block after incisional surgery in rats. METHODS The authors administered perisciatic lidocaine (2%), QX-314 (0.2%) followed by dilute capsaicin (0.05%, 10 min later), or vehicle in rats and the duration of motor and sensory block to thermal and mechanical stimuli assessed in normal animals and those after incisional surgery to the hind paw. Other animals receiving these injections were evaluated 7 weeks later by behavior and histology for potential neurotoxicity. RESULTS Perineural injection of the combination not only attenuated mechanical hypersensitivity for 72 h after incision but also resulted in delayed onset mechanical hypersensitivity several weeks later, accompanied by degeneration of central terminals of isolectin B4 (nonpeptidergic) and calcitonin gene-related peptide-containing (peptidergic) afferents in the ipsilateral spinal cord. Dorsal root ganglia ipsilateral to injection of the combination showed increased expression of activating transcription factor-3 and satellite cell activation. CONCLUSIONS Combined administration of local anesthetics with the transient receptor potential vanilloid 1 agonist capsaicin induced a near complete blockade of incision-induced hypersensitivity for several days. However, the same combination induced delayed mechanical hypersensitivity and neurotoxicity in naïve rats. Combination of these drugs in these concentrations is likely to result in neurotoxicity, and the safety of other concentrations warrants further study.
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Interaction of local anesthetics with biomembranes consisting of phospholipids and cholesterol: mechanistic and clinical implications for anesthetic and cardiotoxic effects. Anesthesiol Res Pract 2013; 2013:297141. [PMID: 24174934 PMCID: PMC3794646 DOI: 10.1155/2013/297141] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/13/2013] [Accepted: 08/17/2013] [Indexed: 01/13/2023] Open
Abstract
Despite a long history in medical and dental application, the molecular mechanism and precise site of action are still arguable for local anesthetics. Their effects are considered to be induced by acting on functional proteins, on membrane lipids, or on both. Local anesthetics primarily interact with sodium channels embedded in cell membranes to reduce the excitability of nerve cells and cardiomyocytes or produce a malfunction of the cardiovascular system. However, the membrane protein-interacting theory cannot explain all of the pharmacological and toxicological features of local anesthetics. The administered drug molecules must diffuse through the lipid barriers of nerve sheaths and penetrate into or across the lipid bilayers of cell membranes to reach the acting site on transmembrane proteins. Amphiphilic local anesthetics interact hydrophobically and electrostatically with lipid bilayers and modify their physicochemical property, with the direct inhibition of membrane functions, and with the resultant alteration of the membrane lipid environments surrounding transmembrane proteins and the subsequent protein conformational change, leading to the inhibition of channel functions. We review recent studies on the interaction of local anesthetics with biomembranes consisting of phospholipids and cholesterol. Understanding the membrane interactivity of local anesthetics would provide novel insights into their anesthetic and cardiotoxic effects.
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Shen J, Fox LE, Cheng J. Swim therapy reduces mechanical allodynia and thermal hyperalgesia induced by chronic constriction nerve injury in rats. PAIN MEDICINE 2013; 14:516-25. [PMID: 23438327 DOI: 10.1111/pme.12057] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Neuropathic pain is common and often difficult to treat because it generally does not respond well to the currently available pain medications or nerve blocks. Recent studies in both humans and animals have suggested that exercise may induce a transient analgesia and reduce acute pain in normal healthy individuals. We examined whether swim therapy could alleviate neuropathic pain in rats. DESIGN Rats were trained to swim over a 2-week period in warm water. After the rats were trained, neuropathic pain was induced by constricting the right sciatic nerve, and regular swimming was resumed. The sensitivity of each hind paw was monitored using the Hargreaves test and von Frey test to evaluate the withdrawal response thresholds to heat and touch. RESULTS The paw ipsilateral to the nerve ligation expressed pain-like behaviors including thermal hyperalgesia and mechanical allodynia. Regular swim therapy sessions significantly reduced the mechanical allodynia and thermal hyperalgesia. Swim therapy had little effect on the withdrawal thresholds for the contralateral paw. In addition, swim therapy alone did not alter the thermal or mechanical thresholds of normal rats. CONCLUSIONS The results suggest that regular exercise, including swim therapy, may be an effective treatment for neuropathic pain caused by nerve injuries. This study, showing that swim therapy reduces neuropathic pain behavior in rats, provides a scientific rationale for clinicians to test the efficacy of exercise in the management of neuropathic pain. It may prove to be a safe and cost-effective therapy in a variety of neuropathic pain states.
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Affiliation(s)
- Jun Shen
- Departments of Neurosciences, Cleveland Clinic, Cleveland, Ohio, USA
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