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Objective: The transient receptor potential cation channel, subfamily V (vanilloid), member 1 (TRPV1) mediates pain perception to thermal and chemical stimuli in peripheral neurons. The cannabinoid receptor type 1 (CB1), on the other hand, promotes analgesia in both the periphery and the brain. TRPV1 and CB1 have also been implicated in learned fear, which involves the association of a previously neutral stimulus with an aversive event. In this review, we elaborate on the interplay between CB1 receptors and TRPV1 channels in learned fear processing. Methods: We conducted a PubMed search for a narrative review on endocannabinoid and endovanilloid mechanisms on fear conditioning. Results: TRPV1 and CB1 receptors are activated by a common endogenous agonist, arachidonoyl ethanolamide (anandamide), Moreover, they are expressed in common neuroanatomical structures and recruit converging cellular pathways, acting in concert to modulate fear learning. However, evidence suggests that TRPV1 exerts a facilitatory role, whereas CB1 restrains fear responses. Conclusion: TRPV1 and CB1 seem to mediate protective and aversive roles of anandamide, respectively. However, more research is needed to achieve a better understanding of how these receptors interact to modulate fear learning. [ABSTRACT FROM AUTHOR]

Eugenol, a known vanilloid, was frequently used in dentistry as a local analgesic in addition, antibacterial and neuroprotective effects were also reported. Eugenol, capsaicin and many vanilloids are interacting with the transient receptor potential vanilloid 1 (TRPV1) in mammals and the TRPV1 is activated by noxious heat. The pharmacological manipulation of the TRPV1 has been shown to have therapeutic value. Caenorhabditis elegans (C. elegans) express TRPV orthologs (e.g. OCR-2, OSM-9) and it is a commonly used animal model system to study nociception as it displays a well-defined and reproducible nocifensive behavior. After exposure to vanilloid solutions, C. elegans wild type (N2) and mutants were placed on petri dishes divided in quadrants for heat stimulation. Thermal avoidance index was used to phenotype each tested C. elegans experimental groups. The results showed that eugenol, vanillin and zingerone can hamper nocifensive response of C. elegans to noxious heat (32–35 °C) following a sustained exposition. Also, the effect was reversed 6 h post exposition. Furthermore, eugenol and vanillin did not target specifically the OCR-2 or OSM-9 but zingerone did specifically target the OCR-2 similarly to capsaicin. Further structural and physicochemical analyses were performed. Key parameters for quantitative structure-property relationships (QSPR), quantitative structure-activity relationships (QSAR) and frontier orbital analyses suggest similarities and dissimilarities amongst the tested vanilloids and capsaicin in accordance with the relative anti-nociceptive effects observed. [ABSTRACT FROM AUTHOR]

Although TRPV1 ion channel has been attracting researchers' attention for many years, its functions in animal organisms, the principles of regulation, and the involvement in pathological processes have not yet been fully clarified. Mutagenesis experiments and structural studies have identified the structural features of the channel and binding sites for its numerous ligands; however, these studies are far from conclusion. This review summarizes recent achievements in the TRPV1 research with special focus on structural and functional studies of the channel and on its ligands, which are extremely diverse in their nature and interaction specificity to TRPV1. Particular attention was given to the effects of numerous endogenous agonists and antagonists that can fine-tune the channel sensitivity to its usual activators, such as capsaicin, heat, acids, or their combination. In addition to the pain sensing not covered in this review, the TRPV1 channel was found to be involved in the regulation of many important physiological and pathological processes and, therefore, can be considered as a promising therapeutic target in the treatment of various diseases, such as pneumonia, ischemia, diabetes, epilepsy, schizophrenia, psoriasis, etc. [ABSTRACT FROM AUTHOR]

Neutrophils migrate to sites of infection where they phagocytose, degranulate, and/or, in the presence of appropriate stimuli, release decondensed chromatin strands (called neutrophil extracellular traps, NETs) for trapping and possibly killing microorganisms. NET formation is characterized by marked morphological cell changes, in particular within the nucleus. Lytic NET formation can be observed in neutrophils undergoing cell death, which is referred to as NETosis. Dysregulation of NET production and/or degradation can exert pathogenic effects, contributing to the pathogenesis of various diseases, including cystic fibrosis, autoimmune diseases and inflammatory conditions. By employing a phenotypic assay based on high-content imaging and analysis, we screened a library of biologically active compounds and identified vanilloids as a novel class of chemical compounds able to hinder NETosis induction and NET release. Vanilloids also markedly decrease cytosolic ROS production. The identification of novel vanilloid NET inhibitors, able to stop excessive or aberrant NET production might offer new therapeutic options for those disorders displaying NET overproduction.

Neutrophils migrate to sites of infection where they phagocytose, degranulate, and/or, in the presence of appropriate stimuli, release decondensed chromatin strands (called neutrophil extracellular traps, NETs) for trapping and possibly killing microorganisms. NET formation is characterized by marked morphological cell changes, in particular within the nucleus. Lytic NET formation can be observed in neutrophils undergoing cell death, which is referred to as NETosis. Dysregulation of NET production and/or degradation can exert pathogenic effects, contributing to the pathogenesis of various diseases, including cystic fibrosis, autoimmune diseases and inflammatory conditions. By employing a phenotypic assay based on high-content imaging and analysis, we screened a library of biologically active compounds and identified vanilloids as a novel class of chemical compounds able to hinder NETosis induction and NET release. Vanilloids also markedly decrease cytosolic ROS production. The identification of novel vanilloid NET inhibitors, able to stop excessive or aberrant NET production might offer new therapeutic options for those disorders displaying NET overproduction. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Thermoregulatory side effects hinder the development of transient receptor potential vanilloid‐1 (TRPV1) antagonists as new painkillers. While many antagonists cause hyperthermia, a well‐studied effect, some cause hypothermia. The mechanisms of this hypothermia are unknown and were studied herein. Methods: Two hypothermia‐inducing TRPV1 antagonists, the newly synthesized A‐1165901 and the known AMG7905, were used in physiological experiments in rats and mice. Their pharmacological profiles against rat TRPV1 were studied in vitro. Results: Administered peripherally, A‐1165901 caused hypothermia in rats by either triggering tail‐skin vasodilation (at thermoneutrality) or inhibiting thermogenesis (in the cold). A‐1165901‐induced hypothermia did not occur in rats with desensitized (by an intraperitoneal dose of the TRPV1 agonist resiniferatoxin) sensory abdominal nerves. The hypothermic responses to A‐1165901 and AMG7905 (administered intragastrically or intraperitoneally) were absent in Trpv1−/− mice, even though both compounds evoked pronounced hypothermia in Trpv1+/+ mice. In vitro, both A‐1165901 and AMG7905 potently potentiated TRPV1 activation by protons, while potently blocking channel activation by capsaicin. Conclusion: TRPV1 antagonists cause hypothermia by an on‐target action: on TRPV1 channels on abdominal sensory nerves. These channels are tonically activated by protons and drive the reflectory inhibition of thermogenesis and tail‐skin vasoconstriction. Those TRPV1 antagonists that cause hypothermia further inhibit these cold defences, thus decreasing body temperature. Significance: TRPV1 antagonists (of capsaicin activation) are highly unusual in that they can cause both hyper‐ and hypothermia by modulating the same mechanism. For drug development, this means that both side effects can be dealt with simultaneously, by minimizing these compounds’ interference with TRPV1 activation by protons. [ABSTRACT FROM AUTHOR]

In this study, a series of 20 structurally similar vanilloids (Vn) were tested for their antiproliferative effects against 12 human cancer cells: human breast (MCF-7 and MDA-MB-231), cervical (HeLa), ovarian (Caov-3), lung (A549), liver (HepG2), colorectal (HT-29 and HCT116), nasopharyngeal (CNE-1 and HK-1), and leukemic (K562 and CEM-SS) cancer cells. Among all the tested vanilloids, Vn16 (6-shogaol) exhibited the most potent cytotoxic effects against human colorectal cancer cells (HT-29). The apoptotic induction effects exhibited by Vn16 on HT-29 cells were confirmed using dual staining fluorescence microscopy and enzyme-linked immunosorbent assay. The effects of Vn16 on regulation of 43 apoptotic-related markers were determined in HT-29. The results suggested that 8 apoptotic markers (caspase 8, BAD, BAX, second mitochondrial-derived activator, caspase 3, survivin, bcl-2, and cIAP-2) were either upregulated or downregulated. These results further support the chemopreventive properties of foods that contain vanilloids. [ABSTRACT FROM AUTHOR]

Aims: To systematically assess all available evidence on efficacy and safety of vanilloids for treating neurogenic lower urinary tract dysfunction (NLUTD) in patients with multiple sclerosis (MS). Methods: This systematic review and meta‐analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) statement. Studies were identified by electronic search of Cochrane register, Embase, Medline, Scopus, (last search January 8, 2016). Results: After screening of 7848 abstracts, 4 randomized controlled trials (RCTs) and 3 prospective cohort studies were included. Pooled data from three RCTs evaluating intravesical capsaicin showed the standardized mean difference to be −2.16 (95% confidence interval [CI] −2.87 to −1.45) in incontinence episodes per 24 h and −0.54 (95%CI −1.03 to −0.05) in voids per 24 h. There was no statistically significant effect on maximum cystometric capacity and maximum storage detrusor pressure. Overall, adverse events were reported by >50% of the patients, most commonly were pelvic pain, facial flush, worsening of incontinence, autonomic dysreflexia, urinary tract infection and haematuria. Risk of bias and confounding was relevant in both RCTs and non‐RCTs. Conclusions: Preliminary data suggest that intravesical vanilloids might be effective for treating NLUTD in patients with MS. However, the safety profile seems unfavorable, the overall quality of evidence is low and no licensed substance is currently available warranting well‐designed, adequately sampled and properly powered RCTs. [ABSTRACT FROM AUTHOR]

Much of our knowledge of the endocannabinoid system in schizophrenia comes from behavioral measures in rodents, like prepulse inhibition of the acoustic startle and open-field locomotion, which are commonly used along with neurochemical approaches or drug challenge designs. Such methods continue to map fundamental mechanisms of sensorimotor gating, hyperlocomotion, social interaction, and underlying monoaminergic, glutamatergic, and GABAergic disturbances. These strategies will require, however, a greater use of neurophysiological tools to better inform clinical research. In this sense, electrophysiology and viral vector-based circuit dissection, like optogenetics, can further elucidate how exogenous cannabinoids worsen (e.g., tetrahydrocannabinol, THC) or ameliorate (e.g., cannabidiol, CBD) schizophrenia symptoms, like hallucinations, delusions, and cognitive deficits. Also, recent studies point to a complex endocannabinoid-endovanilloid interplay, including the influence of anandamide (endogenous CB1 and TRPV1 agonist) on cognitive variables, such as aversive memory extinction. In fact, growing interest has been devoted to TRPV1 receptors as promising therapeutic targets. Here, these issues are reviewed with an emphasis on the neurophysiological evidence. First, we contextualize imaging and electrographic findings in humans. Then, we present a comprehensive review on rodent electrophysiology. Finally, we discuss how basic research will benefit from further combining psychopharmacological and neurophysiological tools.

“Molecular neurosurgery” is emerging as a new medical concept, and is the combination of two partners: (i) a molecular neurosurgery agent, and (ii) the cognate receptor whose activation results in the selective elimination of a specific subset of neurons in which this receptor is endogenously expressed. In general, a molecular surgery agent is a selective and potent ligand, and the target is a specific cell type whose elimination is desired through the molecular surgery procedure. These target cells have the highest innate sensitivity to the molecular surgery agent usually due to the highest receptor density being in their plasma membrane. The interaction between the ligand and its receptor evokes an overactivity of the receptor. If the receptor is a ligand-activated non-selective cation channel, the overactivity of receptor leads to excess Ca2+ and Na+ influx into the cell and finally cell death. One of the best known examples of such an interaction is the effect of ultrapotent vanilloids on TRPV1-expressing pain-sensing neurons. One intrathecal resiniferatoxin (RTX) dose allows for the receptor-mediated removal of TRPV1+ neurons from the peripheral nervous system. The TRPV1 receptor-mediated ion influx induces necrotic processes, but only in pain-sensing neurons, and usually within an hour. Besides that, target-specific apoptotic processes are also induced. Thus, as a nano-surgery scalpel, RTX removes the neurons responsible for generating pain and inflammation from the peripheral nervous system providing an option in clinical management for the treatment of morphine-insensitive pain conditions. In the future, the molecular surgery concept can also be exploited in cancer research for selectively targeting the specific tumor cell.

Spontaneous pain and function-associated pain are prevalent symptoms of multiple acute and chronic muscle pathologies. We established mouse models for evaluating spontaneous pain and bite-evoked pain from masseter muscle, and determined the roles of transient receptor potential cation channel subfamily V member 1 (TRPV1) and the contribution of TRPV1- or neurokinin 1 (NK1)-dependent nociceptive pathways. Masseter muscle inflammation increased Mouse Grimace Scale scores and face-wiping behavior, which were attenuated by pharmacological or genetic inhibition of TRPV1. Masseter inflammation led to a significant reduction in bite force. Inhibition of TRPV1 only marginally relieved the inflammation-induced reduction of bite force. These results suggest a differential extent of contribution of TRPV1 to the 2 types of muscle pain. However, chemical ablation of TRPV1-expressing nociceptors or chemogenetic silencing of TRPV1-lineage nerve terminals in masseter muscle attenuated inflammation-induced changes in Mouse Grimace Scale scores as well as bite force. Furthermore, ablation of neurons expressing NK1 receptor in trigeminal subnucleus caudalis also prevented both types of muscle pain. Our results suggest that TRPV1 differentially contributes to spontaneous pain and bite-evoked muscle pain, but TRPV1-expressing afferents and NK1-expressing second-order neurons commonly mediate both types of muscle pain. Therefore, manipulation of the nociceptive circuit may provide a novel approach for management of acute or chronic craniofacial muscle pain.Perspective: We report the profound contribution of TRPV1 to spontaneous muscle pain but not to bite-evoked muscle pain. These 2 types of muscle pain are transmitted through a common nociceptive pathway. These results may help to develop new strategies to manage multiple modes of muscle pain simultaneously by manipulating pain circuits. [ABSTRACT FROM AUTHOR]

Much of our knowledge of the endocannabinoid system in schizophrenia comes from behavioral measures in rodents, like prepulse inhibition of the acoustic startle and open-field locomotion, which are commonly used along with neurochemical approaches or drug challenge designs. Such methods continue to map fundamental mechanisms of sensorimotor gating, hyperlocomotion, social interaction, and underlying monoaminergic, glutamatergic, and GABAergic disturbances. These strategies will require, however, a greater use of neurophysiological tools to better inform clinical research. In this sense, electrophysiology and viral vector-based circuit dissection, like optogenetics, can further elucidate how exogenous cannabinoids worsen (e.g., tetrahydrocannabinol, THC) or ameliorate (e.g., cannabidiol, CBD) schizophrenia symptoms, like hallucinations, delusions, and cognitive deficits. Also, recent studies point to a complex endocannabinoid-endovanilloid interplay, including the influence of anandamide (endogenous CB1 and TRPV1 agonist) on cognitive variables, such as aversive memory extinction. In fact, growing interest has been devoted to TRPV1 receptors as promising therapeutic targets. Here, these issues are reviewed with an emphasis on the neurophysiological evidence. First, we contextualize imaging and electrographic findings in humans. Then, we present a comprehensive review on rodent electrophysiology. Finally, we discuss how basic research will benefit from further combining psychopharmacological and neurophysiological tools. [ABSTRACT FROM AUTHOR]

"Molecular neurosurgery" is emerging as a new medical concept, and is the combination of two partners: (i) a molecular neurosurgery agent, and (ii) the cognate receptor whose activation results in the selective elimination of a specific subset of neurons in which this receptor is endogenously expressed. In general, a molecular surgery agent is a selective and potent ligand, and the target is a specific cell type whose elimination is desired through the molecular surgery procedure. These target cells have the highest innate sensitivity to themolecular surgery agent usually due to the highest receptor density being in their plasma membrane. The interaction between the ligand and its receptor evokes an overactivity of the receptor. If the receptor is a ligand-activated non-selective cation channel, the overactivity of receptor leads to excess Ca2+ and Na+ influx into the cell and finally cell death. One of the best known examples of such an interaction is the effect of ultrapotent vanilloids on TRPV1-expressing pain-sensing neurons. One intrathecal resiniferatoxin (RTX) dose allows for the receptor-mediated removal of TRPV1+ neurons from the peripheral nervous system. The TRPV1 receptor-mediated ion influx induces necrotic processes, but only in pain-sensing neurons, and usually within an hour. Besides that, target-specific apoptotic processes are also induced. Thus, as a nano-surgery scalpel, RTX removes the neurons responsible for generating pain and inflammation from the peripheral nervous system providing an option in clinical management for the treatment of morphine-insensitive pain conditions. In the future, the molecular surgery concept can also be exploited in cancer research for selectively targeting the specific tumor cell. [ABSTRACT FROM AUTHOR]

Aim of the study To assess the effectiveness of TRPV1 modulators in animal model of Chronic fatigue syndrome (CFS). To assess central and peripheral behavioral activity of TRPV1 modulators. Material and methods CFS was induced by forcing the rats to swim for 10 min for 21 consecutive days. The rats were treated with capsaicin (TRPV1 agonist, 2.5 mg/kg) and n- tert -butylcyclohexanol (TRPV1 antagonist, 10 mg/kg) for 21 days 30 min before the exposure to stress procedure. The behavioral consequence of CFS was measured in terms of immobility time, grip strength, locomotor activity, and anxiety level using Rota rod, Actophotometer, and Elevated plus maze model respectively. The other parameters include Plasma corticosterone, adrenal gland and spleen weight, complete blood count, blood urea niterogen (BUN), Lactate dehydrogenase (LDH), Lipid peroxidation, catalase and reduced glutathione (GSH). Results and discussion TRPV1 modulators reversed (p < 0.05) the increase in immobility period, anxiety, spleen weight, BUN and LDH levels, and MDA levels along with decrease in grip strength, locomotor activity, plasma corticosterone, adrenal gland weight, catalase, and GSH. There was also significant increase in total WBC count when compared with the disease control group. The reversal was attributed to modulation of HPA axis, oxidative stress, anaerobic respiration product, muscle degradation product. Conclusion The present study reveals the effectiveness of n- tert -butylcyclohexanol and capsaicin against chronic fatigue syndrome. The mechanism of action can be attributed to inhibition of TRPV1 channel and thereby modulating pain perception, neuroendocrine function, oxidative stress and immune function. [ABSTRACT FROM AUTHOR]

Capsaicin, the pungent ingredient of the hot chili pepper, is known to act on the transient receptor potential cation channel vanilloid subfamily member 1 (TRPV1). TRPV1 is involved in somatic and visceral peripheral inflammation, in the modulation of nociceptive inputs to spinal cord and brain stem centers, as well as the integration of diverse painful stimuli. In this review, we first describe the chemical and pharmacological properties of capsaicin and its derivatives in relation to their analgesic properties. We then consider the biochemical and functional characteristics of TRPV1, focusing on its distribution and biological effects within the somatosensory and viscerosensory nociceptive systems. Finally, we discuss the use of capsaicin as an agonist of TRPV1 to model acute inflammation in slices and other ex vivo preparations. [ABSTRACT FROM AUTHOR]

The transient receptor potential vanilloid 1 ion channel (TRPV1) is a ligand-gated nonselective calcium-permeant cation channel involved in the detection of a wide variety of chemical and physical noxious stimuli, ranging from exogenous and endogenous ligands to noxious heat (>42 °C) and low pH (pH < 5.2). Due to its central role in pain and hyperalgesia, TRPV1 is considered a relevant therapeutic target for the development of analgesic and anti-inflammatory drugs potentially useful to relieve chronic, neuropathic, and inflammatory pain and to treat disorders such as inflammatory bowel disease. In this view, the availability of in vitro assays for the screening of novel TRPV1 modulators is highly desirable. Since TRPV1 activation leads to an increase in the intracellular calcium (Ca 2+ ) levels, the use of Ca 2+ fluorescent indicators represent a valuable and sensitive tool for monitoring such intracellular changes. In this chapter, we describe methods for recording and monitoring Ca 2+ signals through the fluorescent indicators Fluo-4 acetoxymethyl (AM) and Fura-2 AM in HEK-293 cells transfected with TRPV1 or other thermoTRP channels., (© 2023. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Capsaicin, the pungent ingredient of the hot chili pepper, is known to act on the transient receptor potential cation channel vanilloid subfamily member 1 (TRPV1). TRPV1 is involved in somatic and visceral peripheral inflammation, in the modulation of nociceptive inputs to spinal cord and brain stem centers, as well as the integration of diverse painful stimuli. In this review, we first describe the chemical and pharmacological properties of capsaicin and its derivatives in relation to their analgesic properties. We then consider the biochemical and functional characteristics of TRPV1, focusing on its distribution and biological effects within the somatosensory and viscerosensory nociceptive systems. Finally, we discuss the use of capsaicin as an agonist of TRPV1 to model acute inflammation in slices and other ex vivo preparations.

Background and Purpose Evodiamine, a racemic quinazolinocarboline alkaloid isolated from the traditional Chinese medicine Evodiae fructus, has been reported to act as an agonist of the transient receptor potential vanilloid type-1 ( TRPV1) cation channel both in vitro and in vivo. Evodiamine is structurally different from all known TRPV1 activators, and has significant clinical potential as a thermogenic agent. Nevertheless, the molecular bases for its actions are still poorly understood. Experimental Approach To investigate the structure-activity relationships of evodiamine, the natural racemate was resolved, and a series of 23 synthetic analogues was prepared, using as the end point the intracellular Ca2+ elevation in HEK-293 cells stably overexpressing either the human or the rat recombinant TRPV1. Key Results S-(+) evodiamine was more efficacious and potent than R-(−) evodiamine, and a new potent lead ( Evo30) was identified, more potent than the reference TRPV1 agonist, capsaicin. In general, potency and efficacy correlated with the lipophilicity of the analogues. Like other TRPV1 agonists, several synthetic analogues could efficiently desensitize TRPV1 to activation by capsaicin. Conclusions and Implications Evodiamine qualifies as structurally unique lead structure to develop new potent TRPV1 agonists/desensitizers. Linked Articles This article is part of a themed section on the pharmacology of TRP channels. To view the other articles in this section visit [ABSTRACT FROM AUTHOR]

The article presents an analysis of the mechanisms of involved in platelet aggregation and activation, focusinf on the properties of vanilloids and the receptor, TRPV1. It explores the effects of vanilloids, particularly capsaicinoids, on platelets to determine their potential therapeutic benefits. It suggests that vanilloids appear to modulate the function of platelets.

Abstract: Quinone reductase (QR) inducing activity, a biomarker for Phase II enzyme induction, was detected in a crude ginger rhizome ethanolic extract using a murine hepatoma cell (Hepa 1c1c7) bioassay. An ethyl acetate-partitioned fraction became enriched in QR inducing activity with a CD value (concentration required to double QR specific activity) of 7μg/ml and was further separated by silica flash chromatography. The four major fractions recovered exhibited CD values ranging 10–20μg/mL for QR inducing activity. 1H NMR analysis revealed an abundance of gingerols in the first 3 fractions, and this led to a comparative assessment of QR inducing and anti-inflammatory activities among [6]-gingerol and structurally related vanilloids from ginger and other spices. [6]-Dehydroshogaol (DHSG), a minor component of fresh ginger, had QR inducing activity (CD=8.4μM) of comparable potency to the well known cancer preventive agent, curcumin (CD=4.3μM). In contrast, [6]-gingerol the major pungent component of ginger showed less potent QR inducing activity (CD=55μM) and capsaicin exhibited the weakest inducing activity (CD=103μM). [6]-Shogaol, [6]-DHSG and curcumin were also potent inhibitors of nitric oxide (NO) synthesis, inhibiting 50% NO evolution in activated macrophages at levels of 10–12μM (IC50 values). Comparatively, IC50 values for [6]-gingerol and capsaicin were about an order of magnitude greater (less potent) at 90μM and 169μM, respectively. This appears to be the first report of biological activities of [6]-DHSG, and Phase II enzyme-inducing ability of shogoal and gingerol. [ABSTRACT FROM AUTHOR]

The transient receptor potential (TRP) vanilloid receptor subtype 1 (TRPV1) is a ligand-gated, Ca2+-permeable ion channel in the TRP superfamily of channels. We report the establishment of the first neuronal model expressing recombinant human TRPV1 (SH-SY5YhTRPV1). SH-SY5Y human neuroblastoma cells were stably transfected with hTRPV1 using the Amaxa Biosystem (hTRPV1 in pIREShyg2 with hygromycin selection). Capsaicin, olvanil, resiniferatoxin and the endocannabinoid anandamide increased [Ca2+]i with potency (EC50) values of 2.9 nmol/L, 34.7 nmol/L, 0.9 nmol/L and 4.6 μmol/L, respectively. The putative endovanilloid N-arachidonoyl-dopamine increased [Ca2+]i but this response did not reach a maximum. Capsaicin, anandamide, resiniferatoxin and olvanil mediated increases in [Ca2+]i were inhibited by the TRPV1 antagonists capsazepine and iodo-resiniferatoxin with potencies ( KB) of ∼70 nmol/L and 2 nmol/L, respectively. Capsaicin stimulated the release of pre-labelled [3H]noradrenaline from monolayers of SH-SY5YhTRPV1 cells with an EC50 of 0.6 nmol/L indicating amplification between [Ca2+]i and release. In a perfusion system, we simultaneously measured [3H]noradrenaline release and [Ca2+]i and observed that increased [Ca2+]i preceded transmitter release. Capsaicin treatment also produced a cytotoxic response (EC50 155 nmol/L) that was antagonist-sensitive and mirrored the [Ca2+]I response. This model displays pharmacology consistent with TRPV1 heterologously expressed in standard non-neuronal cells and native neuronal cultures. The advantage of SH-SY5YhTRPV1 is the ability of hTRPV1 to couple to neuronal biochemical machinery and produce large quantities of cells. [ABSTRACT FROM AUTHOR]

Abstract: Starting from ROPA (2), analogues of RTX (1a) modified on the acyl side chain were prepared and evaluated for vanilloid activity in HEK-293 cells over-expressing the human recombinant TRPV1. The ROPA motif provided an enhancement of potency sufficient to expand the range of vanillyl surrogates to structural elements (e.g., an unsubstituted phenyl ring) that afford inactive analogues in compounds from the capsaicin series. [Copyright &y& Elsevier]

In recent years, important improvements in the management of patients with neurogenic or non-neurogenic detrusor overactivity and urge incontinence have been brought about by the introduction of vanilloids and botulinum toxins in urology. In this review we introduce the new therapeutic options, provides basic information, and summarize the results experienced so far. [ABSTRACT FROM AUTHOR]

The article provides a summary of developments in pharmacological therapy for the overactive bladder (OAB), particularly with regards to available antimuscarinic drugs and the newer non-anticholinergic drugs. Antimuscarinic drugs include tolterodine, trospium, darifenacin and solifenacin. Other types of drugs are those acting on membrane channels, those with mixed actions, adrenoceptors, antidepressants, prostaglandin synthesis inhibitors and vasopressin analogues.

Capsaicin, the pungent ingredient of hot chilli pepper, has been recently shown to induce apoptosis in several cell lines through a not well known mechanism. Here, we investigated the role of the vanilloid capsaicin in the death regulation of the human cancer androgen-resistant cell line PC-3. Capsaicin inhibited the growth of PC-3 with an IC50 of 20 μM cells and induced cell apoptosis, as assessed by flow cytometry and nuclei staining with DAPI. Capsaicin induced apoptosis in prostate cells by a mechanism involving reactive oxygen species generation, dissipation of the mitochondrial inner transmembrane potential (ΔΨm) and activation of caspase 3. Capsaicin-induced apoptosis was not reduced by the antagonist capsazepine in a dose range from 0.1 μM to 20 μM, suggesting a receptor-independent mechanism. To study the in vivo effects of capsaicinoids, PC-3 cells were grown as xenografts in nude mice. Subcutaneous injection of either capsaicin or capsazepine (5 mg/kg body weight) in nude mice suppressed PC-3 tumor growth in all tumors investigated and induced apoptosis of tumor cells. Our data show a role for capsaicin against androgen-independent prostate cancer cells in vitro and in vivo and suggest that capsaicin is a promising anti-tumor agent in hormone-refractory prostate cancer, which shows resistance to many chemotherapeutic agents. [ABSTRACT FROM AUTHOR]

Abstract: Rat neutrophils express the mRNA encoding for transient receptor potential (TRP) V1. However, capsaicin-stimulated [Ca2+]i elevation occurred only at high concentrations (≥100 μM). This response was substantially decreased in a Ca2+-free medium. Vanilloids displayed similar patterns of Ca2+ response with the rank order of potency as follows: scutigeral>resiniferatoxin>capsazepine>capsaicin=olvanil>isovelleral. Arachidonyl dopamine (AAD), an endogenous ligand for TRPV1, failed to desensitize the subsequent capsaicin challenge. Capsaicin-induced Ca2+ response was not affected by 8-bromo-cyclic ADP-ribose (8-Br-cADPR), the ryanodine receptor blocker, but was slightly attenuated by 1-[6-[17β-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122), the inhibitor of phospholipase C-coupled processes, 1-[β-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole (SKF-96365), the blocker of receptor-gated and store-operated Ca2+ (SOC) channels, 2-aminoethyldiphenyl borate (2-APB), the blocker of D-myo-inositol 1,4,5-trisphospahte (IP3) receptor and Ca2+ influx, and by ruthenium red, a blocker of TRPV channels, and enhanced by the Ca2+ channels blocker, cis-N-(2-phenylcyclopentyl)azacyclotridec-1-en-2-amine (MDL-12330A) and Na+-deprivation. In addition, capsaicin had no effect on the plasma membrane Ca2+-ATPase activity or the production of nitric oxide (NO) and reactive oxygen intermediates (ROI) or on the total thiols content. Capsaicin (≥100 μM) inhibited the cyclopiazonic acid (CPA)-induced store-operated Ca2+ entry (SOCE). In the absence of external Ca2+, the robust Ca2+ entry after subsequent addition of Ca2+ was decreased by capsaicin in CPA-activated cells. Capsaicin alone increased the actin cytoskeleton, and also increased the actin filament content in cell activation with CPA. These results indicate that capsaicin activates a TRPV1-independent non-SOCE pathway in neutrophils. The reorganization of the actin cytoskeleton is probably involved in the capsaicin inhibition of SOCE. [Copyright &y& Elsevier]

Abstract: Vanilloid receptor subtype-1 (TRPV1), the founding member of the vanilloid receptor-like transient receptor potential channel family, is a non-selective cation channel that responds to noxious stimuli such as low pH, painful heat and irritants. In the present study, we show, as means of reverse transcriptase-polymerase chain reaction and Western blot analysis, that the vanilloid TRPV1 receptor is expressed in the prostate epithelial cell lines PC-3 and LNCaP as well as in human prostate tissue. The kinetic parameters inferred from [125I]-resiniferatoxin binding were in concordance with data of TRPV1 receptors expressed in other tissues. The contribution of the endogenously expressed TRPV1 channel to intracellular calcium concentration increase in the prostate cells was studied by measuring changes in Fura-2 fluorescence by fluorescence microscopy. Addition of capsaicin, (R)-methanandamide and resiniferatoxin to prostate cells induced a dose-dependent increase in the intracellular calcium concentration that was reversed by the vanilloid TRPV1 receptor antagonist capsazepine. These results indicate that the vanilloid TRPV1 receptor is expressed and functionally active in human prostate cells. [Copyright &y& Elsevier]

Objectives: The ATP-gated purinergic receptor P2X3 is expressed by small diameter sensory neurons and has been identified in normal and neurogenic human bladder suburothelial fibres. Animal models have shown that ATP is released by the urothelium during bladder distension, suggesting a mechanosensory role for P2X3 receptors in normal bladder function. Successful treatment of spinal neurogenic detrusor overactivity (NDO) with intravesical resiniferatoxin (RTX), which partly acts on suburothelial C fibres, provides evidence for the emergence of a C fibre-mediated spinal reflex. The aim of this study was to investigate the possible role of P2X3-positive innervation in this pathological voiding reflex by comparing suburothelial P2X3 immunoreactivity of controls and in patients with NDO before and after intravesical RTX.Methods: Bladder biopsies were obtained from 8 controls and 20 patients with refractory NDO enrolled in a trial of intravesical RTX. P2X3 nerve fibre density and intensity were studied in the specimens by immunohistochemistry.Results: P2X3-IR nerve fibres were significantly increased in patients with NDO compared to controls (p=0.014). Thirteen patients had pre- and post-RTX biopsies available for immunohistochemistry; 5 of them responded clinically and 8 were non-responders. In the 5 patients who responded to RTX, there was a significant decrease in P2X3-positive fibres (p=0.032), whereas in non-responders, P2X3-IR nerve fibre density did not change significantly.Conclusions: In patients with NDO, the numbers of P2X3-IR nerve fibres were increased in the suburothelium. There was a significant decrease in P2X3 immunoreactivity in responders to RTX, indicating a potential pathophysiological role for the P2X3 expressing fibres. [Copyright &y& Elsevier]

Chemical compounds that contain the vanillyl moiety (4-hydroxy-3-methoxybenzyl) are collectively classified as vanilloids. Vanilloid phytochemicals can be found in a variety of sources, some of which are routinely consumed by humans throughout the world. The dietary and/or medicinal use of vanilloids may be effective in inhibiting or reversing carcinogenesis, which has sparked a considerable interest in these compounds as potential chemopreventive or chemotherapeutic agents. Certain vanilloids are also valuable as pharmacological tools for investigating neurobiology, and have been proven effective in alleviating neurogenic pain and inflammation. Recently several vanilloids have demonstrated the ability to induce apoptosis in various cell types. Vanilloids can interact with proteins and membranes to initiate pleiotropic effects, some of which are potentially cytotoxic. Certain vanilloids bind to cation channels on nociceptive sensory neurons to regulate Ca2+ uptake, which can promote neurotoxicity resulting in apoptosis and necrosis. Furthermore, some vanilloids appear to interfere with enzymatic processes in the plasma membrane and the mitochondria by functioning as coenzyme Q antagonist. This can promote reactive oxygen species production and/or the disruption of redox homeostasis resulting in apoptosis. This review will examine the cellular targets, cytotoxic effects, and the downstream effector mechanisms associated with vanilloid-induced apoptosis. [ABSTRACT FROM AUTHOR]

Capsaicin-sensitive sensory nerves are widely distributed in the cardiovascular system. They are activated by a variety of physical and chemical stimuli, characteristically by capsaicin acting via the vanilloid receptor VR1, and have a role in the regulation of peripheral vascular resistance and maintenance of homeostasis via their afferent and efferent functions. Cannabinoids, a recently discovered family of extracellular signalling molecules, can act at cannabinoid (CB) receptors expressed on sensory nerves, to cause inhibition of sensory neurotransmitter release. There is recent evidence, however, that anandamide, an endogenous cannabinoid, can activate VR1, coexpressed with CB receptors on the same sensory nerve terminals, causing a release of sensory neurotransmitter, vasorelaxation and hypotension. Hence, anandamide can elicit opposite actions, inhibition via CB receptors and excitation via VR1, on sensory neurotransmission. The possible biological significance of this is discussed. [Copyright &y& Elsevier]

Two cannabinoid (CB) receptors are known in humans, CB1 and CB2. They are phylogenetically ancient. Studies suggest CB receptors occur in mammals, birds, amphibians, fish, sea urchins, mollusks, leeches, and Hydra vulgaris. The CB receptor genes from some of these animals have been cloned and sequenced. These sequences were used to construct a phylogenetic tree of CB genes. The gene tree is rooted in an ancestral CB gene that predates the divergence of vertebrates and invertebrates. Thus the primordial CB receptor evolved at least 600 million years ago, a date broadly consistent with the Cambrian explosion. Since then, one clade of invertebrates, the Ecdysozoa, has secondarily lost the genes coding CB receptors. There is no evidence that animals obtained CB genes from other organisms via horizontal gene transfer. We hypothesize that the primordial CB receptor diverged from a related G-protein coupled receptor, and it linked with a pre-existing ligand, anandamide. Anandamide serves as a ligand for CB receptors as well as vanilloid (VR) receptors. VR receptors regulate the sensation of pain, and may also modulate mood and memory. Our phylogenetic analysis suggests that VR receptors evolved before CB receptors, so anandamide first served as a VR ligand. We speculate that CB receptors, lacking selective constraints, subsequently acquired a mutation that coupled them with 2-AG. A better understanding of CB and VR receptors man enable us to combine their beneficial effects. Dual-signaling ligands such as anandamide have excellent therapeutic potential as analgesics, vasodilators, and anti-cancer agents. [ABSTRACT FROM PUBLISHER]