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Shibata M, Kayama Y, Takizawa T, Ibata K, Shimizu T, Yuzaki M, Suzuki N, Nakahara J. Resilience to capsaicin-induced mitochondrial damage in trigeminal ganglion neurons. Mol Pain 2021; 16:1744806920960856. [PMID: 32985330 PMCID: PMC7536481 DOI: 10.1177/1744806920960856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Capsaicin is an agonist of transient receptor potential cation channel subfamily V member 1 (TRPV1). Strong TRPV1 stimulation with capsaicin causes mitochondrial damage in primary sensory neurons. However, the effect of repetitive and moderate exposure to capsaicin on the integrity of neuronal mitochondria remains largely unknown. Our electron microscopic analysis revealed that repetitive stimulation of the facial skin of mice with 10 mM capsaicin induced short-term damage to the mitochondria in small-sized trigeminal ganglion neurons. Further, capsaicin-treated mice exhibited decreased sensitivity to noxious heat stimulation, indicating TRPV1 dysfunction, in parallel with the mitochondrial damage in the trigeminal ganglion neurons. To analyze the capsaicin-induced mitochondrial damage and its relevant cellular events in detail, we performed cell-based assays using TRPV1-expressing PC12 cells. Dose-dependent capsaicin-mediated mitochondrial toxicity was observed. High doses of capsaicin caused rapid destruction of mitochondrial internal structure, while low doses induced mitochondrial swelling. Further, capsaicin induced a dose-dependent loss of mitochondria and autophagy-mediated degradation of mitochondria (mitophagy). Concomitantly, transcriptional upregulation of mitochondrial proteins, cytochrome c oxidase subunit IV, Mic60/Mitofilin, and voltage-dependent anion channel 1 was observed, which implied induction of mitochondrial biogenesis to compensate for the loss of mitochondria. Collectively, although trigeminal ganglion neurons transiently exhibit mitochondrial damage and TRPV1 dysfunction following moderate capsaicin exposure, they appear to be resilient to such a challenge. Our in vitro data show a dose-response relationship in capsaicin-mediated mitochondrial toxicity. We postulate that induction of mitophagy and mitochondrial biogenesis in response to capsaicin stimulation play important roles in repairing the damaged mitochondrial system.
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Affiliation(s)
- Mamoru Shibata
- Department of Neurology, Keio University School of Medicine, Japan
| | - Yohei Kayama
- Department of Neurology, Keio University School of Medicine, Japan
| | - Tsubasa Takizawa
- Department of Neurology, Keio University School of Medicine, Japan
| | - Keiji Ibata
- Department of Physiology, Keio University School of Medicine, Japan.,Department of Physiology, St. Marianna Medical University, Japan
| | | | - Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Japan
| | - Norihiro Suzuki
- Department of Neurology, Keio University School of Medicine, Japan
| | - Jin Nakahara
- Department of Neurology, Keio University School of Medicine, Japan
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Quantitative Thermal Testing Profiles as a Predictor of Treatment Response to Topical Capsaicin in Patients with Localized Neuropathic Pain. PAIN RESEARCH AND TREATMENT 2017; 2017:7425907. [PMID: 28321335 PMCID: PMC5339491 DOI: 10.1155/2017/7425907] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/15/2017] [Accepted: 01/30/2017] [Indexed: 01/17/2023]
Abstract
There are no reliable predictors of response to treatment with capsaicin. Given that capsaicin application causes heat sensation, differences in quantitative thermal testing (QTT) profiles may predict treatment response. The aim of this study was to determine whether different QTT profiles could predict treatment outcomes in patients with localized peripheral neuropathic pain (PeLNP). We obtained from medical records QTT results and treatment outcomes of 55 patients treated between 2010 and 2013. Warm sensation threshold (WST) and heat pain threshold (HPT) values were assessed at baseline at the treatment site and in the asymptomatic, contralateral area. Responders were defined as those who achieved a > 30% decrease in pain lasting > 30 days. Two distinct groups were identified based on differences in QTT profiles. Most patients (27/31; 87.1%) with a homogenous profile were nonresponders. By contrast, more than half of the patients (13/24, 54.2%) with a nonhomogenous profile were responders (p = 0.0028). A nonhomogenous QTT profile appears to be predictive of response to capsaicin. We hypothesize patients with a partial loss of cutaneous nerve fibers or receptors are more likely to respond. By contrast, when severe nerve damage or normal cutaneous sensations are present, the pain is likely due to central sensitization and thus not responsive to capsaicin. Prospective studies with larger patient samples are needed to confirm this hypothesis.
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Lipina C, Irving AJ, Hundal HS. Mitochondria: a possible nexus for the regulation of energy homeostasis by the endocannabinoid system? Am J Physiol Endocrinol Metab 2014; 307:E1-13. [PMID: 24801388 DOI: 10.1152/ajpendo.00100.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The endocannabinoid system (ECS) regulates numerous cellular and physiological processes through the activation of receptors targeted by endogenously produced ligands called endocannabinoids. Importantly, this signaling system is known to play an important role in modulating energy balance and glucose homeostasis. For example, current evidence indicates that the ECS becomes overactive during obesity whereby its central and peripheral stimulation drives metabolic processes that mimic the metabolic syndrome. Herein, we examine the role of the ECS in modulating the function of mitochondria, which play a pivotal role in maintaining cellular and systemic energy homeostasis, in large part due to their ability to tightly coordinate glucose and lipid utilization. Because of this, mitochondrial dysfunction is often associated with peripheral insulin resistance and glucose intolerance as well as the manifestation of excess lipid accumulation in the obese state. This review aims to highlight the different ways through which the ECS may impact upon mitochondrial abundance and/or oxidative capacity and, where possible, relate these findings to obesity-induced perturbations in metabolic function. Furthermore, we explore the potential implications of these findings in terms of the pathogenesis of metabolic disorders and how these may be used to strategically develop therapies targeting the ECS.
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Affiliation(s)
- Christopher Lipina
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Andrew J Irving
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Harinder S Hundal
- Division of Cell Signalling and Immunology, Sir James Black Centre, College of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
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Szolcsányi J. Capsaicin and sensory neurones: a historical perspective. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2014; 68:1-37. [PMID: 24941663 DOI: 10.1007/978-3-0348-0828-6_1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Capsaicin, the pungent ingredient of red pepper has become not only a "hot" topic in neuroscience but its new target-related unique actions have opened the door for the drug industry to introduce a new chapter of analgesics. After several lines of translational efforts with over 1,000 patents and clinical trials, the 8% capsaicin dermal patch reached the market and its long-lasting local analgesic effect in some severe neuropathic pain states is now well established. This introductory chapter outlines on one hand the historical background based on the author's 50 years of experience in this field and on the other hand emphasizes new scopes, fascinating perspectives in pharmaco-physiology, and molecular pharmacology of nociceptive sensory neurons. Evidence for the effect of capsaicin on C-polymodal nociceptors (CMH), C-mechanoinsensitive (CHMi), and silent C-nociceptors are listed and the features of the capsaicin-induced blocking effects of nociceptors are demonstrated. Common and different characteristics of nociceptor-blocking actions after systemic, perineural, local, intrathecal, and in vitro treatments are summarized. Evidence for the misleading conclusions drawn from neonatal capsaicin pretreatment is presented. Perspectives opened from cloning the capsaicin receptor "Transient Receptor Potential Vanilloid 1" (TRPV1) are outlined and potential molecular mechanisms behind the long-lasting functional, ultrastructural, and nerve terminal-damaging effects of capsaicin and other TRPV1 agonists are summarized. Neurogenic inflammation and the long-list of "capsaicin-sensitive" tissue responses are mediated by an unorthodox dual sensory-efferent function of peptidergic TRPV1-expressing nerve terminals which differ from the classical efferent and sensory nerve endings that have a unidirectional role in neuroregulation. Thermoregulatory effects of capsaicin are discussed in detail. It is suggested that since hyperthermia and burn risk due to enhanced noxious heat threshold are the major obstacles of some TRPV1 antagonists, they could be overcome. The special "multisteric" gating function of the TRPV1 cation channel provides the structural ground for blocking chemical activation of TRPV1 without affecting its responsiveness to physical stimuli. A new chapter of potential analgesics targeting nociceptors is now already supported for pain relief in persistent pathological pain states.
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Szolcsányi J, Pintér E. Transient receptor potential vanilloid 1 as a therapeutic target in analgesia. Expert Opin Ther Targets 2013; 17:641-57. [PMID: 23421411 DOI: 10.1517/14728222.2013.772580] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The selective excitatory action of capsaicin followed by long-term chemoanalgesia due to an action on the 'capsaicin receptor' of C-polymodal nociceptors, cloned 15 years ago, opened up fascinating perspectives for a class of nociceptor blocking analgesics. AREAS COVERED The TRPV1/capsaicin receptor is an integrative, chemoceptive, noxious heat-gated cation channel also gated by several endogenous ligands and sensitized by phosphorylation through intracellular cascades triggered from receptors of bradykinin, prostanoids, NGF and interactions with TRPA1. In this review, types of sensory receptors and unique mechanisms for blocking nociceptor action, e.g., 'pore dilation' intracellular acidosis and the long-term function-related mitochondrial swelling at the nerve terminals and sensory neurons are summarized. In humans the 8% capsaicin dermal patch is already in usage for nondiabetic neuropathic pain and two topical preparations of civamide have also been approved recently for cluster headache and osteoarthritis. Evidence for epidermal nerve terminal loss in humans after topical applications and misleading results on sensory neuron death evoked by TRPV1 agonism in animals are discussed. EXPERT OPINION The unique 'multisteric' gating of TRPV1 channel which is opened and modulated in various conformational changes to natural stimuli differs from the operation of canonical ligand-gated channels and makes it suitable to initiate development of second generation of TRPV1 antagonists without on-target side effects of hyperthermia and risk of burn injury.
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Affiliation(s)
- János Szolcsányi
- University of Pécs Medical School, Department of Pharmacology and Pharmacotherapy , H-7624 Pécs, Szigeti u. 12 , Hungary.
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Spinal anandamide produces analgesia in neuropathic rats: possible CB(1)- and TRPV1-mediated mechanisms. Neuropharmacology 2011; 62:1746-55. [PMID: 22178705 DOI: 10.1016/j.neuropharm.2011.11.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 11/23/2011] [Accepted: 11/29/2011] [Indexed: 11/21/2022]
Abstract
The endocannabinoid anandamide (AEA) activates also transient receptor potential vanilloid-1 (TRPV1) channels. However, no data exist on the potential role of spinal TRPV1 activation by AEA in neuropathic pain. We tested the effect of: 1) AEA (5-100 μg), alone or in the presence of an inhibitor of its hydrolysis, and 2) elevated levels of endogenous AEA (following inhibition of AEA hydrolysis), in CCI rats, and the involvement of TRPV1 or cannabinoid CB(1) receptors in the observed effects. Levels of AEA in the spinal cord of CCI rats were measured following all treatments. AEA (50 μg) displayed anti-allodynic and anti-hyperalgesic effects which were abolished by previous antagonism of TRPV1, but not CB(1), receptors. Depending on the administered dose, the selective inhibitor of AEA enzymatic hydrolysis, URB597 (10-100 μg), reduced thermal and tactile nociception via CB(1) or CB(1)/TRPV1 receptors. The anti-nociceptive effects of co-administered per se ineffective doses of AEA (5 μg) and URB597 (5 μg) was abolished by antagonism of CB(1), but not TRPV1, receptors. Spinal AEA levels were increased after CCI, slightly increased further by URB597, 10 μg i.t., and strongly elevated by URB597, 100 μg. Injection of AEA (50 μg) into the lumbar spinal cord led to its dramatic elevation in this tissue, whereas, when a lower dose was used (5 μg) AEA endogenous levels were elevated only in the presence of URB597 (5 μg). We suggest that spinal AEA reduces neuropathic pain via CB(1) or TRPV1, depending on its local concentration.
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Hamtiaux L, Hansoulle L, Dauguet N, Muccioli GG, Gallez B, Lambert DM. Increasing antiproliferative properties of endocannabinoids in N1E-115 neuroblastoma cells through inhibition of their metabolism. PLoS One 2011; 6:e26823. [PMID: 22046372 PMCID: PMC3203169 DOI: 10.1371/journal.pone.0026823] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 10/05/2011] [Indexed: 11/19/2022] Open
Abstract
The antitumoral properties of endocannabinoids received a particular attention these last few years. Indeed, these endogenous molecules have been reported to exert cytostatic, apoptotic and antiangiogenic effects in different tumor cell lines and tumor xenografts. Therefore, we investigated the cytotoxicity of three N-acylethanolamines – N-arachidonoylethanolamine (anandamide, AEA), N-palmitoylethanolamine (PEA) and N-oleoylethanolamine (OEA) - which were all able to time- and dose-dependently reduce the viability of murine N1E-115 neuroblastoma cells. Moreover, several inhibitors of FAAH and NAAA, whose presence was confirmed by RT-PCR in the cell line, induced cell cytotoxicity and favored the decrease in cell viability caused by N-acylethanolamines. The most cytotoxic treatment was achieved by the co-incubation of AEA with the selective FAAH inhibitor URB597, which drastically reduced cell viability partly by inhibiting AEA hydrolysis and consequently increasing AEA levels. This combination of molecules synergistically decreased cell proliferation without inducing cell apoptosis or necrosis. We found that these effects are independent of cannabinoid, TRPV1, PPARα, PPARγ or GPR55 receptors activation but seem to occur through a lipid raft-dependent mechanism. These findings further highlight the interest of targeting the endocannabinoid system to treat cancer. More particularly, this emphasizes the great potential benefit of designing novel anti-cancerous therapies based on the association of endocannabinoids and inhibitors of their hydrolysis.
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Affiliation(s)
- Laurie Hamtiaux
- Medicinal Chemistry, Cannabinoid and Endocannabinoid Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Laurie Hansoulle
- Medicinal Chemistry, Cannabinoid and Endocannabinoid Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Nicolas Dauguet
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Giulio G. Muccioli
- Bioanalysis and Pharmacology of Bioactive Lipids Laboratory, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Bernard Gallez
- Biomedical Magnetic Resonance, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Didier M. Lambert
- Medicinal Chemistry, Cannabinoid and Endocannabinoid Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
- * E-mail:
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Zavitsanou K, Dalton VS, Wang H, Newson P, Chahl LA. Receptor changes in brain tissue of rats treated as neonates with capsaicin. J Chem Neuroanat 2010; 39:248-55. [DOI: 10.1016/j.jchemneu.2010.01.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 01/19/2010] [Accepted: 01/19/2010] [Indexed: 02/03/2023]
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Catanzaro G, Rapino C, Oddi S, Maccarrone M. Anandamide increases swelling and reduces calcium sensitivity of mitochondria. Biochem Biophys Res Commun 2009; 388:439-42. [DOI: 10.1016/j.bbrc.2009.08.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Accepted: 08/05/2009] [Indexed: 12/19/2022]
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Horvath G, Kekesi G, Nagy E, Benedek G. The role of TRPV1 receptors in the antinociceptive effect of anandamide at spinal level. Pain 2008; 134:277-284. [PMID: 17533116 DOI: 10.1016/j.pain.2007.04.032] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 01/31/2007] [Accepted: 04/23/2007] [Indexed: 11/22/2022]
Abstract
While it is well known that the endogenous cannabinoid receptor ligand anandamide also activates the transient receptor potential vanilloid1 (TRPV1) receptors, there has been no in vivo study indicating the role of the TRPV1 receptors in the antinociceptive effect of anandamide at spinal level. The goal of this study was to determine the effect of inhibition of TRPV1 receptors by capsazepine on the antinociceptive potency of anandamide after intrathecal administration. Anandamide alone (1, 30 or 100 microg) dose-dependently decreased carrageenan-induced thermal hyperalgesia, however, the highest dose caused temporary excitation and vocalization, suggesting the pain-inducing potential of anandamide. Capsazepine (10 or 20 microg) by itself did not change the pain sensitivity markedly, but the lower dose increased it, and the higher dose decreased the antinociceptive effect of 30 microg anandamide. Furthermore, both doses of capsazepine decreased the efficacy of the largest dose of anandamide. These results show that TRPV1 receptor activation plays a substantial role in the antinociceptive effects of anandamide at spinal level. The effect of the inhibition on TRPV1 receptors depended on the dose applied. We presume that coactivation of the cannabinoid and TRPV1 receptors by anandamide provides elevated antinociception through the release of antinociceptive endogenous ligands at spinal level.
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Affiliation(s)
- Gyöngyi Horvath
- Department of Physiology, Faculty of Medicine, University of Szeged, P.O. Box 427, H-6701 Szeged, Hungary Department of Physiotherapy, Faculty of Health Sciences, University of Szeged, Hungary
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Hong S, Agresta L, Guo C, Wiley JW. The TRPV1 receptor is associated with preferential stress in large dorsal root ganglion neurons in early diabetic sensory neuropathy. J Neurochem 2008; 105:1212-22. [PMID: 18182051 DOI: 10.1111/j.1471-4159.2008.05220.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Chronic diabetic neuropathy is associated with peripheral demyelination and degeneration of nerve fibers. The mechanism(s) underlying neuronal injury in diabetic sensory neuropathy remain poorly understood. Recently, we reported increased expression and function of transient receptor potential vanilloid 1 (TRPV1) in large dorsal root ganglion (DRG) neurons in diabetic sensory neuropathy. In this study, we examined the effects of TRPV1 activation on cell injury pathways in this subpopulation of neurons in the streptozotocin-induced diabetic rat model. Large DRG neurons from diabetic (6-8 weeks) rats displayed increased oxidative stress and activation of cell injury markers compared with healthy controls. Capsaicin (CAP) treatment induced decreased labeling of MitoTracker Red and increased cytosolic cytochrome c and activation of caspase 3 in large neurons isolated from diabetic rats. CAP treatment also induced oxidative stress in large diabetic DRG neurons, which was blocked by pre-treatment with caspase or calpain inhibitor. In addition, both mu-calpain expression and calpain activity were significantly increased in DRG neurons from diabetic rats after CAP treatment. Treatment with capsazepine, a competitive TRPV1 antagonist, markedly reduced these abnormalities in vitro and prevented activation of cell injury in large DRG neurons in diabetic rats in vivo. These results suggest that activation of the TRPV1 receptor activates pathways associated with caspase-dependent and calpain-dependent stress in large DRG neurons in STZ-diabetic rats. Activation of the TRPV1 receptor may contribute to preferential neuronal stress in large DRG neurons relatively early in diabetic sensory neuropathy.
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Affiliation(s)
- Shuangsong Hong
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA.
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Downer EJ, Gowran A, Campbell VA. A comparison of the apoptotic effect of Δ9-tetrahydrocannabinol in the neonatal and adult rat cerebral cortex. Brain Res 2007; 1175:39-47. [PMID: 17884022 DOI: 10.1016/j.brainres.2007.07.076] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Revised: 07/24/2007] [Accepted: 07/30/2007] [Indexed: 11/21/2022]
Abstract
The maternal use of cannabis during pregnancy results in a number of cognitive deficits in the offspring that persist into adulthood. The endocannabinoid system has a role to play in neurodevelopmental processes such as neurogenesis, migration and synaptogenesis. However, exposure to phytocannabinoids, such as Delta(9)-tetrahydrocannabinol, during gestation may interfere with these events to cause abnormal patterns of neuronal wiring and subsequent cognitive impairments. Aberrant cell death evoked by Delta(9)-tetrahydrocannabinol may also contribute to cognitive deficits and in cultured neurones Delta(9)-tetrahydrocannabinol induces apoptosis via the CB(1) cannabinoid receptor. In this study we report that Delta(9)-tetrahydrocannabinol (5-50 microM) activates the stress-activated protein kinase, c-jun N-terminal kinase, and the pro-apoptotic protease, caspase-3, in in vitro cerebral cortical slices obtained from the neonatal rat brain. The proclivity of Delta(9)-tetrahydrocannabinol to impact on these pro-apoptotic signalling molecules was not observed in in vitro cortical slices obtained from the adult rat brain. In vivo, subcutaneous administration of Delta(9)-tetrahydrocannabinol (1-30 mg/kg) activated c-jun N-terminal kinase, caspase-3 and cathepsin-D, and induced DNA fragmentation in the cerebral cortex of neonatal rats. In contrast, in vivo administration of Delta(9)-tetrahydrocannabinol to adult rats was not associated with the apoptotic pathway in the cerebral cortex. The data provide evidence which supports the hypothesis that the neonatal rat brain is more vulnerable to the neurotoxic influence of Delta(9)-tetrahydrocannabinol, suggesting that the cognitive deficits that are observed in humans exposed to marijuana during gestation may be due, in part, to abnormal engagement of the apoptotic cascade during brain development.
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Affiliation(s)
- Eric J Downer
- Department of Physiology and Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland
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Lauria G, Morbin M, Lombardi R, Capobianco R, Camozzi F, Pareyson D, Manconi M, Geppetti P. Expression of capsaicin receptor immunoreactivity in human peripheral nervous system and in painful neuropathies. J Peripher Nerv Syst 2006; 11:262-71. [PMID: 16930289 DOI: 10.1111/j.1529-8027.2006.0097.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We describe the expression of the capsaicin receptor (TRPV1) in human peripheral nervous system (PNS) and its changes in sural nerve and skin nerve fibers of patients with painful neuropathy. Dorsal root ganglion (DRG), root, and spinal cord autopsy specimens from subjects without PNS diseases were immunoassayed with anti-TRPV1 antibodies. Bright-field and confocal microscope studies using anti-TRPV1, protein gene product 9.5 (PGP 9.5), and unique-beta-tubulin (TuJ1) antibodies were performed in skin biopsies from 15 healthy subjects and 10 painful neuropathies. The density of intraepidermal nerve fiber (IENF) labeled by each antibody was quantified. Sural nerve biopsies from three patients with painful, one patient with nonpainful diabetic neuropathy, and two patients with multifocal motor neuropathy used as controls were immunoassayed with anti-TRPV1 antibodies and investigated by immunoelectron microscopy. TRPV1 strongly labeled laminae I and II of dorsal horns, most small-size and some medium-size DRG neurons, and small-diameter axons of dorsal roots. In sural nerve, TRPV1 was expressed within the cytoplasm of most unmyelinated and some small myelinated axons, in the muscular lamina of epineural vessels, and in the endothelium of endoneurial vessels. The density of IENF labeled by TRPV1, PGP 9.5, and TuJ1 did not differ. TRPV1 colocalized with TuJ1 in all IENF and dermal nerve bundles. Painful neuropathies showed a diffuse loss of TRPV1-positive axons both in the sural nerve and in the skin. Our findings demonstrated that TRPV1 is normally expressed throughout the nociceptive pathway of PNS and that TRPV1-positive peripheral nerve fibers degenerate in painful neuropathies.
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Affiliation(s)
- Giuseppe Lauria
- Neuromuscular Diseases, National Neurological Institute 'Carlo Besta', Milan, Italy.
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Chapter 2 History of Ion Channels in the Pain Sensory System. CURRENT TOPICS IN MEMBRANES 2006. [DOI: 10.1016/s1063-5823(06)57001-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Tóth A, Boczán J, Kedei N, Lizanecz E, Bagi Z, Papp Z, Edes I, Csiba L, Blumberg PM. Expression and distribution of vanilloid receptor 1 (TRPV1) in the adult rat brain. ACTA ACUST UNITED AC 2005; 135:162-8. [PMID: 15857679 DOI: 10.1016/j.molbrainres.2004.12.003] [Citation(s) in RCA: 339] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Revised: 12/10/2004] [Accepted: 12/13/2004] [Indexed: 01/13/2023]
Abstract
The vanilloid receptor (TRPV1 or VR1) is a molecular integrator of various painful stimuli, including capsaicin, acid, and high temperature. It can also be activated by endogenous ligands, like the cannabinoid 1 receptor (CB1) agonist anandamide. TRPV1 is well characterized at the terminals of sensory nerves involved in the pain pathway. There is also evidence that TRPV1 is expressed in the brain but little is known about its function. Here, using commercially available specific antibodies to investigate the localization of TRPV1 in the brain of the rat, we report that TRPV1 was expressed in hippocampus, cortex, cerebellum, olfactory bulb, mesencephalon and hindbrain. Immunohistochemical analyses showed high expression in the cell bodies and dendrites of neurons in the hippocampus and in the cortex. To address the question of subcellular localization, immunoelectronmicroscopy was used. TRPV1-like staining was detected in the synapses (mostly, but not exclusively in post-synaptic dendritic spines), on the end feet of astrocytes and in pericytes. In summary, TRPV1 expression shows wide distribution in the brain of the rat, being found in astrocytes and pericytes as well as in neurons. Its localization is consistent with multiple functions within the central nervous system, including the regulation of brain vasculature.
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Affiliation(s)
- Attila Tóth
- Molecular Mechanisms of Tumor Promotion Section, Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Bernardini N, Neuhuber W, Reeh PW, Sauer SK. Morphological evidence for functional capsaicin receptor expression and calcitonin gene-related peptide exocytosis in isolated peripheral nerve axons of the mouse. Neuroscience 2004; 126:585-90. [PMID: 15183508 DOI: 10.1016/j.neuroscience.2004.03.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2004] [Indexed: 10/26/2022]
Abstract
Rat sciatic nerve axons express capsaicin, proton and heat sensitivity and respond to stimulation with a Ca2+-dependent and graded calcitonin gene-related peptide (CGRP) release. In this study we demonstrate that similar functions, including capsaicin-induced CGRP release, are to be found in the desheathed sciatic nerve of the mouse. We have morphologically investigated the mechanisms of this axonal release in regions away from the active zones of synapses. Capsaicin receptor 1 (TRPV1) and CGRP immunostaining was performed using electron microscopic visualization. TRPV1 was identified in the axoplasm and inside vesicles--presumably on axonal transport--as well as in considerable quantity in the axonal plasma membrane of unmyelinated nerve fibers. Most of the unmyelinated axons were immunopositive for CGRP and in unstimulated nerves CGRP-containing vesicles almost entirely filled the axoplasm. After capsaicin stimulation (10(-6) M for 5 min), the fibers appeared depleted of CGRP with only few vesicles remaining as well as some residual staining of the axoplasm. In addition a large number of vesicles were fused with the axonal membrane, forming classical exocytotic figures--the omega structures--lined with CGRP immunoreactive product. These results present morphological evidence for the distribution of TRPV1 along unmyelinated axons in peripheral nerve and also provide the first demonstration of vesicular neuropeptide exocytosis along unmyelinated axons in peripheral nerve.
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Affiliation(s)
- N Bernardini
- Institut für Physiologie und Experimentelle Pathophysiologie, Erlangen-Universität, Universitätstrasse 17, 91054 Erlangen, Germany
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17
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Szolcsányi J, Sándor Z, Petho G, Varga A, Bölcskei K, Almási R, Riedl Z, Hajos G, Czéh G. Direct evidence for activation and desensitization of the capsaicin receptor by N-oleoyldopamine on TRPV1-transfected cell, line in gene deleted mice and in the rat. Neurosci Lett 2004; 361:155-8. [PMID: 15135917 DOI: 10.1016/j.neulet.2003.12.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Effects of the endogenous lipid N-oleoyldopamine (OLDA) were analyzed on the rTRPV1-expressing HT1080 human fibrosarcoma cell line (HT5-1), on cultured rat trigeminal neurons, on the noxious heat threshold of rats and on nocifensive behavior of TRPV1 knockout mice. The EC(50) of capsaicin and OLDA on (45)Ca accumulation of rTRPV1-expressing HT5-1 cells was 36 nM and 1.8 microM, respectively. The efficacy of OLDA was 60% as compared to the maximum response of capsaicin. OLDA (330 nM to 3.3 microM) caused a transient increase in fluorescence of fura-2 loaded cultured small trigeminal neurons of the rat and rTRPV1-transfected HT5-1 cells measured with a ratiometric technique. Repeated application of OLDA and capsaicin caused similar desensitization in the Ca(2+) transients both in cultured neurons and rTRPV1-transfected HT5-1 cells. In the rat intraplantar injection of OLDA (5 nmol) decreased the noxious heat threshold by 6-9 degrees C and this response was strongly inhibited by the TRPV1 antagonist iodoresiniferatoxin (0.05 nmol intraplantarly (i.pl.)). In wild-type mice OLDA (50 nmol i.pl.) evoked paw lifting/licking which was significantly less sustained in TRPV1 knockout mice. It is concluded that on TRPV1 capsaicin receptors OLDA is 50 times less potent than capsaicin and it might serve as an endogenous ligand for TRPV1 in the rat, but more likely in humans.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Capsaicin/pharmacology
- Cell Line, Tumor
- Dopamine/analogs & derivatives
- Dopamine/pharmacology
- Dose-Response Relationship, Drug
- Hot Temperature/adverse effects
- Humans
- Ligands
- Mice
- Mice, Knockout
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Nociceptors/drug effects
- Nociceptors/metabolism
- Pain/chemically induced
- Pain/genetics
- Pain/metabolism
- Pain Threshold/drug effects
- Pain Threshold/physiology
- Rats
- Receptors, Drug/deficiency
- Receptors, Drug/drug effects
- Receptors, Drug/genetics
- Transfection
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Affiliation(s)
- J Szolcsányi
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Neuropharmacology Research Group of the Hungarian Academy of Sciences, University of Pécs, Szigeti u. 12, H-7624 Pécs, Hungary.
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18
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Price TJ, Patwardhan A, Akopian AN, Hargreaves KM, Flores CM. Modulation of trigeminal sensory neuron activity by the dual cannabinoid-vanilloid agonists anandamide, N-arachidonoyl-dopamine and arachidonyl-2-chloroethylamide. Br J Pharmacol 2004; 141:1118-30. [PMID: 15006899 PMCID: PMC1574881 DOI: 10.1038/sj.bjp.0705711] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
1. Peripheral cannabinoids have been shown to suppress nociceptive neurotransmission in a number of behavioral and neurophysiological studies. It is not known, however, whether cannabinoids exert this action through direct interactions with nociceptors in the periphery and/or if other processes are involved. To gain a better understanding of the direct actions of cannabinoid-vanilloid agonists on sensory neurons, we examined the effects of these compounds on trigeminal ganglion (TG) neurons in vitro. 2. AEA (EC(50)=11.0 microM), NADA (EC(50)=857 nM) and arachidonyl-2-chloroethylamide ACEA (EC(50)=14.0 microM) each evoked calcitonin gene-related peptide (CGRP) release from TG neurons. The TRPV1 antagonists iodo-resiniferatoxin (I-RTX) and capsazepine (CPZ) each obtunded AEA-, NADA-, ACEA- and capsaicin (CAP)-evoked CGRP release with individually equivalent IC(50)'s for each of the compounds (I-RTX IC(50) range=2.6-4.0 nM; CPZ IC(50) range=523-1140 microM). 3. The pro-inflammatory mediator prostaglandin E(2) significantly increased the maximal effect of AEA-evoked CGRP release without altering the EC(50). AEA, ACEA and CAP stimulated cAMP accumulation in TG neurons in a calcium- and TRPV1-dependent fashion. Moreover, the protein kinase inhibitor staurosporine significantly inhibited AEA- and CAP-evoked CGRP release. 4. The pungency of AEA, NADA, ACEA and CAP in the rat eye-wipe assay was also assessed. Interestingly, when applied intraocularly, NADA or CAP each produced nocifensive responses, while AEA or ACEA did not. 5. Finally, the potential inhibitory effects of these cannabinoids on TG nociceptors were evaluated. Neither AEA nor ACEA decreased CAP-evoked CGRP release. Furthermore, neither of the cannabinoid receptor type 1 antagonists SR141716A nor AM251 had any impact on either basal or CAP-evoked CGRP release. AEA also did not inhibit 50 mM K(+)-evoked CGRP release and did not influence bradykinin-stimulated inositol phosphate accumulation. 6. We conclude that the major action of AEA, NADA and ACEA on TG neurons is excitatory, while, of these, only NADA is pungent. These findings are discussed in relation to our current understanding of interactions between the cannabinoid and vanilloid systems and nociceptive processing in the periphery.
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MESH Headings
- Aminobutyrates/pharmacology
- Animals
- Arachidonic Acid/antagonists & inhibitors
- Arachidonic Acid/chemistry
- Arachidonic Acid/pharmacology
- Arachidonic Acids/antagonists & inhibitors
- Arachidonic Acids/chemistry
- Arachidonic Acids/pharmacology
- Calcitonin Gene-Related Peptide/antagonists & inhibitors
- Calcitonin Gene-Related Peptide/metabolism
- Calcium Channels/drug effects
- Capsaicin/analogs & derivatives
- Capsaicin/antagonists & inhibitors
- Capsaicin/pharmacology
- Dinoprostone/pharmacology
- Diterpenes/pharmacology
- Dopamine/analogs & derivatives
- Dopamine/chemistry
- Dopamine/pharmacology
- Endocannabinoids
- Ganglia, Spinal/cytology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/physiology
- Male
- Polyunsaturated Alkamides
- Rats
- Rats, Sprague-Dawley
- Receptor, Cannabinoid, CB1/agonists
- Receptor, Cannabinoid, CB1/drug effects
- Receptor, Cannabinoid, CB1/metabolism
- Receptor, Cannabinoid, CB2/agonists
- Receptor, Cannabinoid, CB2/drug effects
- Receptor, Cannabinoid, CB2/metabolism
- Receptors, Drug/agonists
- Receptors, Drug/drug effects
- Staurosporine/pharmacology
- TRPC Cation Channels
- TRPV Cation Channels
- Trigeminal Ganglion/cytology
- Trigeminal Ganglion/drug effects
- Trigeminal Ganglion/physiology
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Affiliation(s)
- Theodore J Price
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, U.S.A
| | - Amol Patwardhan
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, U.S.A
| | - Armen N Akopian
- Department of Endodontics, The University of Texas Health Science Center at San Antonio, U.S.A
| | - Kenneth M Hargreaves
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, U.S.A
- Department of Endodontics, The University of Texas Health Science Center at San Antonio, U.S.A
| | - Christopher M Flores
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, U.S.A
- Department of Endodontics, The University of Texas Health Science Center at San Antonio, U.S.A
- Author for correspondence:
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19
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Kárai LJ, Russell JT, Iadarola MJ, Oláh Z. Vanilloid receptor 1 regulates multiple calcium compartments and contributes to Ca2+-induced Ca2+ release in sensory neurons. J Biol Chem 2004; 279:16377-87. [PMID: 14963041 DOI: 10.1074/jbc.m310891200] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Vanilloid receptor 1 belongs to the transient receptor potential ion channel family and transduces sensations of noxious heat and inflammatory hyperalgesia in nociceptive neurons. These neurons contain two vanilloid receptor pools, one in the plasma membrane and the other in the endoplasmic reticulum. The present experiments characterize these two pools and their functional significance using calcium imaging and 45Ca uptake in stably transfected cells or dorsal root ganglion neurons. The plasma membrane localized receptor is directly activated by vanilloids. The endoplasmic reticulum pool was demonstrated to be independently activated with 20 microm capsaicin or 1.6 microm resiniferatoxin using a bathing solution containing 10 microm Ruthenium Red (to selectively block plasma membrane-localized receptors) and 100 microm EGTA. We also demonstrate an overlap between the endoplasmic reticulum-localized vanilloid receptor regulated stores and thapsigargin-sensitive stores. Direct depletion of calcium via activation of endoplasmic reticulum-localized vanilloid receptor 1 triggered store operated calcium entry. Furthermore, we found that, in the presence of low extracellular calcium (10(-5) m), either 2 microm capsaicin or 0.1 nm-1.6 microm resiniferatoxin caused a pronounced calcium-induced calcium release in either vanilloid receptor-expressing neurons or heterologous expression systems. This phenomenon may allow new insight into how nociceptive neuron function in response to a variety of nociceptive stimuli both acutely and during prolonged nociceptive signaling.
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Affiliation(s)
- László J Kárai
- Neuronal Gene Expression Unit, Pain and Neurosensory Mechanisms Branch, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA
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