Expression Of Vanilloid Receptor Research Articles

Opposing chemosensory functions of closely related gustatory receptors

In the fruit fly Drosophila melanogaster, gustatory sensory neurons express taste receptors that are tuned to distinct groups of chemicals, thereby activating neural ensembles that elicit either feeding or avoidance behavior. Members of a family of ligand -gated receptor channels, the Gustatory receptors (Grs), play a central role in these behaviors. In general, closely related, evolutionarily conserved Gr proteins are co-expressed in the same type of taste neurons, tuned to chemically related compounds, and therefore triggering the same behavioral response. Here, we report that members of the Gr28 subfamily are expressed in largely non-overlapping sets of taste neurons in Drosophila larvae, detect chemicals of different valence, and trigger opposing feeding behaviors. We determined the intrinsic properties of Gr28 neurons by expressing the mammalian Vanilloid Receptor 1 (VR1), which is activated by capsaicin, a chemical to which wild-type Drosophila larvae do not respond. When VR1 is expressed in Gr28a neurons, larvae become attracted to capsaicin, consistent with reports showing that Gr28a itself encodes a receptor for nutritious RNA. In contrast, expression of VR1 in two pairs of Gr28b.c neurons triggers avoidance to capsaicin. Moreover, neuronal inactivation experiments show that the Gr28b.c neurons are necessary for avoidance of several bitter compounds. Lastly, behavioral experiments of Gr28 deficient larvae and live Ca2+ imaging studies of Gr28b.c neurons revealed that denatonium benzoate, a synthetic bitter compound that shares structural similarities with natural bitter chemicals, is a ligand for a receptor complex containing a Gr28b.c or Gr28b.a subunit. Thus, the Gr28 proteins, which have been evolutionarily conserved over 260 million years in insects, represent the first taste receptor subfamily in which specific members mediate behavior with opposite valence.

Opposing chemosensory functions of closely related gustatory receptors.

In the fruit fly Drosophila melanogaster, gustatory sensory neurons express taste receptors that are tuned to distinct groups of chemicals, thereby activating neural ensembles that elicit either feeding or avoidance behavior. Members of a family of ligand -gated receptor channels, the Gustatory receptors (Grs), play a central role in these behaviors. In general, closely related, evolutionarily conserved Gr proteins are co-expressed in the same type of taste neurons, tuned to chemically related compounds, and therefore triggering the same behavioral response. Here, we report that members of the Gr28 subfamily are expressed in largely non-overlapping sets of taste neurons in Drosophila larvae, detect chemicals of different valence, and trigger opposing feeding behaviors. We determined the intrinsic properties of Gr28 neurons by expressing the mammalian Vanilloid Receptor 1 (VR1), which is activated by capsaicin, a chemical to which wild-type Drosophila larvae do not respond. When VR1 is expressed in Gr28a neurons, larvae become attracted to capsaicin, consistent with reports showing that Gr28a itself encodes a receptor for nutritious RNA. In contrast, expression of VR1 in two pairs of Gr28b.c neurons triggers avoidance to capsaicin. Moreover, neuronal inactivation experiments show that the Gr28b.c neurons are necessary for avoidance of several bitter compounds. Lastly, behavioral experiments of Gr28 deficient larvae and live Ca2+ imaging studies of Gr28b.c neurons revealed that denatonium benzoate, a synthetic bitter compound that shares structural similarities with natural bitter chemicals, is a ligand for a receptor complex containing a Gr28b.c or Gr28b.a subunit. Thus, the Gr28 proteins, which have been evolutionarily conserved over 260 million years in insects, represent the first taste receptor subfamily in which specific members mediate behavior with opposite valence.

Time course and expression pattern of the neuronal markers in the developing human spinal cord

The aim of this study was to examine the spatio-temporal appearance of different neuronal cell subtypes by analyzing expression patterns of several neuronal markers (calretinin, neurofilament 200 (NF200), vanilloid receptor 1(VR1) and calcitonin gene-related peptide (CGRP)) of the embryonic human spinal cord (SC). Developing human SCs from 11 human conceptuses beetwen 5–10 developmental weeks (DW) were examined by light and electron microscopy and immunofluorescence. Light and electron microscopy revealed different embryonic stages of recognizable structure of the SC. NF200, CGRP and VR1 positive cells were observed in SCs during 5th–6th DW. NF200 was predominantly expressed in the ventral part, indicating presence of motoneurons. As development advanced, NF200 was mainly expressed in the marginal zone. Expression of CGRP was intense during all of the investigated periods, predominantly during the 5th–6th DW pointing to neural sensory differentiation, as opposed to the last DW when reduced expression of CGRP in the marginal layer indicated the terminations of the sensory afferents. Expression of VR1 was highest in the intermediate zone, at the beginning and at the end of the investigated periods, pointing to VR1 spatial pattern in the visceral afferents in the grey matter, while the first signs of calretinin were found in the 9th–10th DW ventrally. Delineating the relationships between factors involved in processes of neuronal differentiation as well as spatial and temporal arrangement of SC interrelated neurons can provide a useful information about normal SC development as well as the insight in possible causes of anomalies and disorders during embryonic life.

Systematic administration of B vitamins attenuates neuropathic hyperalgesia and reduces spinal neuron injury following temporary spinal cord ischaemia in rats

B vitamins have been demonstrated to be effective in treating chronic pain due to peripheral nerve injury. We investigated whether B vitamins could alleviate neuropathic pain and reduce neuron injury following temporary ischaemia in a rat model of spinal cord ischaemia-reperfusion injury (SCII). SCII was produced by transiently blocking the unilateral lumbar arteries in adult male Sprague-Dawley rats. Behavioural and neurochemical signs of neuropathic pain and spinal neuron injury were analysed with and without B vitamin treatment. SCII caused behavioural thermal hyperalgesia and mechanical allodynia and neurochemical alterations, including increased expression of the vanilloid receptor 1 (VR1) and induction of c-Fos, as well as activation of the astrocytes and microglial cells in the spinal cord. Repetitive systemic administration of vitamin B complex (B1/B6/B12 at 33/33/0.5 mg/kg, i.p., daily, for 7-14 consecutive days) significantly reduced thermal hyperalgesia and the increased expression of VR1 and c-Fos, as well as activation of the astrocytes and microglial cells. SCII caused a dramatic decrease of the expression of the rate-limiting enzyme glutamic acid decarboxylase-65 (GAD65), which synthesizes γ-aminobutyric acid (GABA) in the axonal terminals, and β-III-tubulin, and also caused loss of Nissl bodies in the spinal cord. These alterations were largely prevented and rescued by the B vitamin treatment. These findings support the idea that the B vitamins are capable of neuroprotection and antinociception during spinal cord injury due to temporary ischaemia. Rescuing the loss of inhibitory GABAergic tone may reduce spinal central sensitization and contribute to B vitamin-induced analgesia.

Cell-type specific expression of vanilloid receptor 1 in the taste cells of rat circumvallate papillae

The present study demonstrates the first-ever characterization of cell types that express the vanilloid receptor 1 (VR1) in the taste buds of rat circumvallate papillae. We performed electron microscopy to identify the subcellular location. The VR1 immunoreactivity was associated with the endoplasmic reticulum, cytoplasmic vesicles, and plasma membrane of taste cells. These results demonstrate the localization of the VR1 in membranous structures of the taste cells. We used double immunofluorescence histochemistry with taste cell type-specific markers to identify the cell types that express the VR1. The VR1 was detected in all functional taste cell types (Type I, Type II, and Type III cells). Together, our data suggest that the VR1 might play different roles according to the cell types within a taste bud.

Epithelial expression of vanilloid and cannabinoid receptors: a potential role in burning mouth syndrome pathogenesis

Burning mouth syndrome is an intraoral burning sensation in which the oral mucosa has a normal appearance and no medical or dental causes can be found. It remains an unknown disease for which long-term treatment is still lacking. The aim of this study is to assess in epithelial human tongue the expression of three receptors involved in pain transmission, such as a transient receptor potential vanilloid receptor type 1 (TRPV1) which mediates the sensation produced by chilli peppers, cannabinoid receptors type 1 (CB1) and type 2 (CB2), which are pathway-related to TRPV1. Epithelial cells express TRPV1, CB1 and CB2 receptors suggesting a role for these cells in sensory transduction. The study was performed on 8 healthy and 9 BMS patients. All patients underwent a 3-mm punch biopsy at the anterolateral aspect of the tongue close to the tip. Specimens were included in paraffin and serially cut to obtain 6um thick sections. The sections were processed for TRPV1, CB1 and CB2 immunohistochemistry. The analysis showed an altered expression of the studied receptors. In particular we observed an increase of TRPV1, a decrease of CB1 and an increase of CB2 expression in epithelial cells of the tongue with a change in morphological localization. So, these receptors seem to be correlated with BMS. These data could be useful for future characterization of BMS markers and specific therapies.

High expression of vanilloid receptor-1 is associated with better prognosis of patients with hepatocellular carcinoma

The vanilloid receptor-1 (VR1) is a ligand-gated, nonselective cation channel expressed predominantly by sensory neurons, but is also involved in carcinogenesis. To elucidate its role in hepatocarcinogenesis, we analyzed the expression of VR1 receptor in tumor and nontumor tissues from human hepatocellular carcinoma (HCC) samples. In situ hybridization analysis showed overexpression of VR1 mRNAs in 9/15 (60.0%) noncancer and 6/15 (40.0%) HCC samples. Immunohistochemistry of 62 HCC samples showed the expression of VR1 increased from normal liver or chronic hepatitis to cirrhosis. Marked expression of VR1 was noted in the majority [31/38 (81.6%)] of cirrhotic liver samples. In HCC, high expression of VR1 was observed in 30/62 (48.4%) cases. Clinicopathologic evaluation indicated a significant correlation between VR1 expression and histopathologic differentiation ( P=0.001). Univariate analysis indicated that disease-free survival was significantly better in HCC patients with high versus those with low VR1 expression levels ( P= 0.021). Our results indicate that VR1 has anti-HCC progression effects and can be potentially used as a prognostic indicator of HCC. The results suggest the potential beneficiary effects of VR1 expression on the prognosis of patients with HCC.

The molecular basis of urgency: regional difference of vanilloid receptor expression in the human urinary bladder

Treatments targeting vanilloid receptor TRPV1 are effective in some bladder disorders. Our aim was to determine the expression profiles of TRPV1 in regions of human bladder and test the hypothesis that there would be an upregulation of TRPV1 in mucosa of patients with bladder hypersensitivity but not idiopathic detrusor overactivity (IDO). Women with sensory urgency (SU), interstitial cystitis (IC), and IDO were investigated by videourodynamics and cystoscopy. Control biopsies were used for comparison. Biopsies were dissected into mucosa and muscle, and evaluated for TRPV1 mRNA expression using quantitative competitive RT-PCR (QC-RT-PCR). TRPV1 mRNA from SU trigonal mucosa was significantly higher than control trigonal mucosa or SU bladder body mucosa. In contrast, in IDO patients, there was no difference between trigonal mucosa and body mucosa. In IC biopsies, RNA quality was substandard and unable to be used for analysis. The most striking finding was that TRPV1 mRNA expressed in SU trigonal mucosa was significantly inversely correlated with the bladder volume at first sensation of filling during cystometry. No such relationship was seen for IDO trigonal mucosa. No difference was seen in bladder body mucosa from any disease groups compared with age-matched control. The symptoms of SU were associated with the increased expression of TRPV1 mRNA in the trigonal mucosa. No upregulation or regional differences of TRPV1 mRNA were seen in IDO patients. TRPV1 may play a role in SU and premature first bladder sensation on filling.

Re: Liu L, Mansfield KJ, Kristiana I, et al. 2007. The molecular basis of urgency: regional difference of vanilloid receptor expression in the human urinary bladder. Neurourol Urodynam 26:433–438

Re: Liu L, Mansfield KJ, Kristiana I, et al. 2007. The molecular basis of urgency: regional difference of vanilloid receptor expression in the human urinary bladder. Neurourol Urodynam 26:433–438

Expression and characteristics of vanilloid receptor 1 in the rabbit submandibular gland

Vanilloid receptor 1 (VR1) is a polymodal receptor originally found in sensory neurons of the central nervous system. Recent evidence indicates that VR1 is also expressed in non-neuronal tissues. We report here endogenous expression of VR1 in rabbit submandibular gland (SMG) and its possible role in regulating saliva secretion based on: (i) the expression of VR1 mRNA and protein detected in SMG; (ii) VR1 was mainly localized in the basolateral membrane of duct cells and the cytoplasm of acinar cells and also in cytoplasm of primary cultured neonatal rabbit SMG cells; (iii) stimulation of neonatal rabbit SMG cells with capsaicin induced a significant increase in intracellular calcium, and capsazepine, a VR1 antagonist, abolished this increase; (iv) infusion of capsaicin via the external carotid artery to isolated SMG increased saliva secretion of the gland. These findings indicated that VR1 was expressed in SMG and appeared to play an important role in regulating saliva secretion.

Expression of vanilloid receptor 1 in cultured fibroblast

Although the vanilloid receptor 1 (VR1) was originally discovered on primary sensory neurons, its broad tissue expression in non-neuronal cells has been reported on. Recently, VR1 expression was clearly demonstrated in a variety of cutaneous components, such as keratinocytes, glandular epithelium, mast cells and sebocytes, except for melanocytes and fibroblasts. However, we demonstrated the VR1 expression in the cultured human skin fibroblasts as follows. Previously cloned human VR1 primers that corresponded to the expected size of 680 bp by reverse transcriptase polymerase chain reaction were identified on the fibroblasts, the same as was noted for the positive control, the HaCaT cells. A positive immunoreactivity of the VR1 was observed both on fibroblasts and on HaCaT cells by Western blotting analysis. Fibroblasts treated with capsaicin, an agonist to the VR1, induced significant changes of the membrane current and the intracellular calcium level, and these changes were antagonized by capsazepin. Capsaicin treatment also showed a positive immunocytochemistry result. Our results suggest the existence of VR1 on fibroblasts; this receptor is likely to be influenced by ligand-dependent activation.

77 Vanilloid receptor expression in body and trigone of female urinary bladder: changes in urgency without detrusor overactivity

Introduction: Patients with sensory urgency (SU): the symptom complex of urgency associated with pain, burning or discomfort, often accompanied by frequency and nocturia, are difficult to treat. Vanilloid receptors on afferent neurons and on urothelium may participate in signalling from the bladder. Our aim was to examine whether changes in VR1 expression occur in bladder from SU patients compared with controls.Patients: Biopsies from body and trigone were obtained from patients with SU (female, aged 21–82) who had undergone videourodynamics to exclude detrusor overactivity and define first sensation. Asymptomatic age‐matched females with prior history of carcinoma acted as controls. Biopsies were collected into ‘RNALater’. Specimens were dissected into two layers, mucosa and detrusor muscle, before RNA extraction and quantitative competitive RT‐PCR (Mansfield et al 2005 Br J Pharmacol 144: 1089–99).Results: In control biopsies, VR1 mRNA was present in greater density in mucosa than in detrusor muscle (15.3 × 105cf. 4.6 × 105 copies/μg RNA, both n = 15, P < 0.01). In SU, VR1 mRNA expression was significantly higher in trigonal mucosa than in body mucosa (19.1 × 105 cf. 7.4 × 105 copies/μg RNA, n = 21‐‐23, P < 0.01). There was no significant change in VR1 expression in body mucosa from SU specimens compared with matched controls. In SU patients, the level of VR1 expression in trigonal mucosa (but not body mucosa) was significantly inversely correlated with the volume at first bladder sensation (r2 = 0.41, P < 0.01).Conclusion: We hypothesise that excessive afferent signalling via VR1 receptors in the trigone region may be related to an early first bladder sensation and sensory urgency.

Activity and expression of the vanilloid receptor 1 (TRPV1) is altered by long‐term diabetes in epineurial arterioles of the rat sciatic nerve

Epineurial arterioles of the sciatic nerve are innervated by sensory nerves containing calcitonin gene-related peptide (CGRP). We postulated that treating these resistance vessels with capsaicin would cause the release of endogenous CGRP and vascular relaxation. Videomicroscopy was used to examine the effect of capsaicin and neuropeptides on vascular reactivity of epineurial arterioles from control and streptozotocin-induced diabetic rats. Using immunohistochemistry, we examined expression of neuropeptide Y (NPY) and vanilloid receptor 1 in epineurial arterioles. Instead of relaxation, capsaicin was found to cause a concentration-dependent vasoconstriction in epineurial arterioles. The effect of capsaicin was transient, refractory, blocked by capsazepine and duplicated by resiniferatoxin. When examining potential candidates for the mediation of capsaicin-induced constriction, we found that vasopressin (VP), NPY, serotonin (5HT) and endothelin (ET), but not neurokinin A or substance P, caused a concentration-dependent vasoconstriction of epineurial arterioles. Epineurial arterioles express NPY and receptor antagonists to NPY significantly decreased capsaicin-induced vasoconstriction. In long-term diabetic rats, vasoconstriction to capsaicin was significantly attenuated. However, long-term diabetes did not impair vasoconstriction of epineurial arterioles to exogenous VP, NPY, 5HT or ET. Examining the expression of vanilloid receptor 1 in epineurial arterioles from control and long-term diabetic rats, we found that immunoreactivity for vanilloid receptor 1 was decreased by diabetes. These studies suggest that long-term diabetes causes vascular dysfunction in epineurial arterioles of the sciatic nerve that includes a decrease in capsaicin-induced vasoconstriction that is likely due to a decrease in the expression of vanilloid receptor 1.

VR1-Mediated Depressor Effects During High-Salt Intake

This study was designed to test the hypothesis that increased sensitivity of blood pressure to anandamide (AEA), an endocannabinoid compound, occurs during high-salt intake, which can be blocked by a selective vanilloid receptor 1(VR1) antagonist, capsazepine (CAPZ). Intravenous administration of a metabolically stable analog, methanandamide (MethA), dose-dependently decreased mean arterial pressure (MAP) in conscious rats fed a high-sodium diet (HS) for 3 weeks but it had a minimal effect in normal sodium (NS)-treated rats. The MethA-induced decrease in MAP was significantly attenuated but not abolished by CAPZ, or a selective cannabinoid receptor 1 (CB1) antagonist, SR141716A, administered separately in HS-treated rats. The MethA-induced depressor effect was prevented by the combined administration of CAPZ and SR141716A in HS-treated rats. Likewise, administration of capsaicin, a selective VR1 receptor agonist, dose-dependently decreased MAP in both HS- and NS-treated rats. The depressor effect of capsaicin was more profound in HS-treated rats, which was prevented by CAPZ. Western blot showed that expression of VR1 but not CB1 in mesenteric arteries was increased in HS-treated compared with NS-treated rats. Therefore, these data show that: (1) HS upregulates mesenteric VR1 expression; (2) HS increases sensitivity of blood pressure to AEA; and (3) HS-induced enhancement of the depressor effect of AEA can be prevented only when both VR1 and CB1 receptors are blocked. These results indicate that AEA contributes to the prevention of salt induced increases in blood pressure via, at least in part, activating the VR1 receptor.

Expression and Co-Expression of VR1, CGRP, and IB4-Binding Glycoprotein in Dorsal Root Ganglion Neurons in Rats: Differences Between the Disc Afferents and the Cutaneous Afferents

The expression of vanilloid receptor 1 (VR1), calcitonin gene-related peptide (CGRP), and isolectin B4 (IB4)-binding glycoprotein in dorsal root ganglion (DRG) neurons innervating the lumbar disc and the plantar skin was investigated. To characterize the DRG neurons innervating lumbar discs and those innervating cutaneous tissue in rats. Small nociceptive DRG neurons are divided into nerve growth factor (NGF) sensitive and glial cell line-derived neurotrophic factor (GDNF)-sensitive neurons. CGRP and IB4-binding glycoprotein are recognized as specific markers for NGF and GDNF-sensitive neurons, respectively. VR1 is localized in small DRG neurons. Using histochemical staining and retrograde tracing methods, the expression of VR1, CGRP, and IB4-binding glycoprotein in DRG neurons innervating the L5-L6 disc and the plantar skin was examined in rats. DRG neurons innervating the disc showed positive staining as: 23.4% VR1, 54.4% CGRP, and 1.0% IB4-binding glycoprotein. The following distribution was found for DRG neurons innervating the skin: 35.1% VR1, 41.1% CGRP, and 19.5% IB4-binding glycoprotein. Percentages of neurons positive for VR1 and IB4-binding glycoprotein were significantly lower in DRG neurons innervating the disc than in DRG neurons innervating the skin (P < 0.05), while no significant difference was observed in the percentage of neurons positive for CGRP. VR1 is less abundant in lumbar disc than in cutaneous tissue. Our data suggest that nociceptive information from the disc is transmitted mostly by NGF-sensitive neurons, while that from the cutaneous tissue is transmitted by both NGF-sensitive and GDNF-sensitive neurons.

Early Painful Diabetic Neuropathy Is Associated with Differential Changes in the Expression and Function of Vanilloid Receptor 1

Diabetes mellitus is associated with one or more kinds of stimulus-evoked pain including hyperalgesia and allodynia. The mechanisms underlying painful diabetic neuropathy remain poorly understood. Previous studies demonstrate an important role of vanilloid receptor 1 (VR1) in inflammation and injury-induced pain. Here we investigated the function and expression of VR1 in dorsal root ganglion (DRG) neurons isolated from streptozotocin-induced diabetic rats between 4 and 8 weeks after onset of diabetes. DRG neurons from diabetic rats showed significant increases in capsaicin- and proton-activated inward currents. These evoked currents were completely blocked by the capsaicin antagonist capsazepine. Capsaicin-induced desensitization of VR1 was down-regulated, whereas VR1 re-sensitization was up-regulated in DRG neurons from diabetic rats. The protein kinase C (PKC) activator phorbol 12-myristate 13-acetate blunted VR1 desensitization, and this effect was reversible in the presence of the PKC inhibitor bisindolylmaleimide I. Compared with the controls, VR1 protein was decreased in DRG whole-cell homogenates from diabetic rats, but increased levels of VR1 protein were observed on plasma membranes. Of interest, the tetrameric form of VR1 increased significantly in DRGs from diabetic rats. Increased phosphorylation levels of VR1 were also observed in DRG neurons from diabetic rats. Colocalization studies demonstrated that VR1 expression was increased in large myelinated A-fiber DRG neurons, whereas it was decreased in small unmyelinated C-fiber neurons as a result of diabetes. These results suggest that painful diabetic neuropathy is associated with altered cell-specific expression of the VR1 receptor that is coupled to increased function through PKC-mediated phosphorylation, oligomerization, and targeted expression on the cell surface membrane.

Expression of vanilloid receptor-1 in epithelial cells of human antral gastric mucosa

ObjectiveCapsaicin, which acts by binding to the vanilloid receptor-1 (VR1), has been shown to give protection against gastric mucosal injury and to enhance healing of gastric ulcers. Although VR1 has recently been reported to be present in non-neural tissues, it is primarily considered to be expressed in nociceptor sensory neurons of small diameter. The aim of the present study was to evaluate the distribution of VR1 immunoreactivity in the normal human gastric mucosa.Material and methodsTen volunteers underwent gastroscopy and biopsies were obtained from the corpus and the antrum. The specimens were labelled immunohistochemically using polyclonal goat anti-VR1 and evaluated at the light- and electronmicroscopic level. Moreover, post-embedding immunogold labelling was performed and subsequently analysed at the electronmicroscopic level.ResultsIn the antrum, VR1 immunoreactivity was located in epithelial cells that fulfilled the criteria of endocrine cells of the “open type”. These cells were located primarily in the neck region of the antral glands and the labelling was concentrated on the microvilli of these cells. At the ultrastructural level, round granulae with differences in electron density were identified in the basal compartment of the labelled cells. VR1 immunoreactivity was also identified in axon-like structures that were located in the lamina propria, often in close vicinity of vessels, in the corpus as well as in the antrum.ConclusionsVR1-immunoreactivity was evident in antral epithelial cells exhibiting characteristics of endocrine-like cells. This may indicate that the gastroprotective effects of capsaicin, which hitherto have been attributed to primary afferent neurons, at least partly may be explained by an action on specific epithelial cells in the antrum.

Nerve growth factor and vanilloid receptor expression, and detrusor instability, after relieving bladder outlet obstruction in rats.

To investigate mRNA expression for nerve growth factor (NGF) and vanilloid receptor TRPV1 in the bladder after relieving bladder outlet obstruction (BOO), and to correlate changes with functional changes of the bladder. Temporary BOO was induced by partial urethral ligation in 40 male Wistar rats. After 3 weeks the obstruction was removed and the rats assessed by cystometry 3 weeks later. The bladder body of each rat was then removed, and NGF and TRPV1 mRNA expression measured by the reverse transcription-polymerase chain reaction. Fifteen sham-operated rats served as controls. Based on the cystometry, 10 of the 40 experimental rats were judged to have an unstable bladder, and the remaining 30 to have normal bladder function. The mean bladder weight in the normal and unstable groups was higher than in the control group, and there was no significant difference between the normal and unstable groups. The bladder contraction pressure was similar in the three groups but the mean contraction interval was markedly shorter in the unstable than in the control and normal groups (P < 0.05). The mRNA expressions of NGF and TRPV1 were higher in the unstable than in the control and normal groups. NGF and TRPV1 were apparently increased in unstable bladder tissue after relieving BOO; these changes may be related to irritative symptoms after correcting BOO.

Orofacial pain: Vanilloid receptor expression in human tooth pulp in relation to inflammation and pain

Orofacial pain: Vanilloid receptor expression in human tooth pulp in relation to inflammation and pain

Expression of vanilloid receptors in rat gastric epithelial cells: role in cellular protection

Vanilloid receptors subtype 1 (VR1), a nonselective cation channel responsive to capsaicin, protons, and noxious heat, has been recently identified in not only neural but also non-neural cells. In the present study, we demonstrated the peripheral expression of VR1 in gastric mucosal epithelial cells and investigated the role of the receptor in cellular protection. The rat gastric mucosal epithelial cell line was used. The expression of VR1 was examined by Western blotting and RT–PCR. Cell damage was induced by immersion in 10% ethanol or acid (pH 4.0) for 30 min, and cell viability was determined by MTT assay. Capsaicin or resiniferatoxin was added 30 min before the challenge with ethanol or acid, while capsazepine or ruthenium red (a VR1 antagonist) was added simultaneously with capsaicin. The distinct expression of VR1 protein and mRNA was detected in rat gastric mucosal epithelial cell line as well as in the rat stomach and spinal cord by Western blotting and RT–PCR, respectively. The cDNA sequence of the PCR product was found to be almost identical to that of the authentic VR1 (99.8%) when the product was subcloned and sequenced. On the other hand, the cell damage induced by ethanol or acid was dose-dependently prevented by pretreatment with capsaicin. The protective effect of capsaicin was mimicked by resiniferatoxin and almost totally abolished by co-addition of capsazepine or ruthenium red. These findings suggest that VR1 is expressed peripherally in gastric mucosal epithelial cells and plays a cellular protective role.