capsazepine and Colitis

Palmitoylethanolamide (PEA) acts via several targets, including cannabinoid CB1 and CB2 receptors, transient receptor potential vanilloid type-1 (TRPV1) ion channels, peroxisome proliferator-activated receptor alpha (PPAR α) and orphan G protein-coupled receptor 55 (GRR55), all involved in the control of intestinal inflammation. Here, we investigated the effect of PEA in a murine model of colitis.. Colitis was induced in mice by intracolonic administration of dinitrobenzenesulfonic acid (DNBS). Inflammation was assessed by evaluating inflammatory markers/parameters and by histology; intestinal permeability by a fluorescent method; colonic cell proliferation by immunohistochemistry; PEA and endocannabinoid levels by liquid chromatography mass spectrometry; receptor and enzyme mRNA expression by quantitative RT-PCR.. DNBS administration caused inflammatory damage, increased colonic levels of PEA and endocannabinoids, down-regulation of mRNA for TRPV1 and GPR55 but no changes in mRNA for CB1 , CB2 and PPARα. Exogenous PEA (i.p. and/or p.o., 1 mg·kg(-1) ) attenuated inflammation and intestinal permeability, stimulated colonic cell proliferation, and increased colonic TRPV1 and CB1 receptor expression. The anti-inflammatory effect of PEA was attenuated or abolished by CB2 receptor, GPR55 or PPARα antagonists and further increased by the TRPV1 antagonist capsazepine.. PEA improves murine experimental colitis, the effect being mediated by CB2 receptors, GPR55 and PPARα, and modulated by TRPV1 channels.

Topics: Administration, Oral; Amides; Animals; Anti-Inflammatory Agents; Benzenesulfonates; Capsaicin; Colitis; Colon; Disease Models, Animal; Endocannabinoids; Ethanolamines; Intestinal Absorption; Male; Mice, Inbred ICR; Oleic Acids; Palmitic Acids; Peroxidase; PPAR alpha; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Receptors, Cannabinoid; RNA, Messenger; TRPV Cation Channels

Rats with experimental colitis suffer from impaired gastric emptying (GE). We previously showed that this phenomenon involves afferent neurons within the pelvic nerve. In this study, we aimed to identify the mediators involved in this afferent hyperactivation. Colitis was induced by trinitrobenzene sulfate (TNBS) instillation. We determined GE, distal front, and geometric center (GC) of intestinal transit 30 min after intragastric administration of a semiliquid Evans blue solution. We evaluated the effects of the transient receptor potential vanilloid type 1 (TRPV1) antagonists capsazepine (5-10 mg/kg) and N-(4-tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl)tetrahydropyrazine-1(2H)carboxamide (BCTC; 1-10 mg/kg) and the calcitonin gene-related peptide (CGRP) receptor antagonist CGRP-(8-37) (150 microg/kg). To determine TRPV1 receptor antagonist sensitivity, we examined their effect on capsaicin-induced relaxations of isolated gastric fundus muscle strips. Immunocytochemical staining of TRPV1 and RT-PCR analysis of TRPV1 mRNA were performed in dorsal root ganglion (DRG) L6-S1. TNBS-induced colitis reduced GE but had no effect on intestinal motility. Capsazepine reduced GE in controls but had no effect in rats with colitis. At doses that had no effects in controls, BCTC and CGRP-(8-37) significantly improved colitis-induced gastroparesis. Capsazepine inhibited capsaicin-induced relaxations by 35% whereas BCTC completely abolished them. TNBS-induced colitis increased TRPV1-like immunoreactivity and TRPV1 mRNA content in pelvic afferent neuronal cell bodies in DRG L6-S1. In conclusion, distal colitis in rats impairs GE via sensitized pelvic afferent neurons. We provided pharmacological, immunocytochemical, and molecular biological evidence that this sensitization is mediated by TRPV1 receptors and involves CGRP release.

Topics: Animals; Calcitonin Gene-Related Peptide; Calcitonin Gene-Related Peptide Receptor Antagonists; Capsaicin; Colitis; Disease Models, Animal; Dose-Response Relationship, Drug; Ganglia, Spinal; Gastric Emptying; Gastrointestinal Motility; Gastroparesis; Intestinal Mucosa; Intestines; Male; Muscle Relaxation; Neurons, Afferent; Peptide Fragments; Pyrazines; Pyridines; Rats; Rats, Wistar; Receptors, Calcitonin Gene-Related Peptide; RNA, Messenger; Signal Transduction; Time Factors; Trinitrobenzenesulfonic Acid; TRPV Cation Channels

A protective role of the transient potential vanilloid receptor 1 (TRPV1) in intestinal inflammation induced by dinitrobenzene sulphonic acid (DNBS) has been recently demonstrated. Curcumin, the major active component of turmeric, is also able to prevent and ameliorate the severity of the damage in DNBS-induced colitis. We evaluated the possibility that curcumin (45 mg kg(-1) day p.o. for 2 days before and 5 days after the induction of colitis) was able to reduce DNBS-induced colitis in mice, by acting as a TRPV1 agonist. Macroscopic damage score, histological damage score and colonic myeloperoxidase (MPO) activity were significantly lower (by 71%, 65% and 73%, respectively; P < 0.01), in animals treated with curcumin compared with untreated animals. Capsazepine (30 mg kg(-1), i.p.), a TRPV1 receptor antagonist, completely abolished the protective effects of curcumin. To extend these data in vitro, Xenopus oocytes expressing rat TRPV1 were examined. Capsaicin-evoked currents (3.3 micromol L(-1)) disappeared subsequent either to removal of the agonist or subsequent to the addition of capsazepine. However, curcumin (30 micromol L(-1)) was ineffective both as regard direct modification of cell membrane currents and as regard interference with capsaicin-mediated effects. As sensitization of the TRPV1 receptor by mediators of inflammation in damaged tissues has been shown previously, our results suggest that in inflamed, but not in normal tissue, curcumin can interact with the TRPV1 receptor to mediate its protective action in DNBS-induced colitis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Benzenesulfonates; Capsaicin; Cell Membrane; Colitis; Curcumin; Male; Membrane Potentials; Mice; Mice, Inbred BALB C; Oocytes; Peroxidase; Severity of Illness Index; TRPV Cation Channels; Xenopus

Primary sensory neurons are important in regard to the initiation and propagation of intestinal inflammation. The vanilloid receptor subtype-1 (VR-1) is a cation channel located on the sensory nerves that, when stimulated, release proinflammatory peptides. Previous reports have indicated that inhibition of VR-1 with capsazepine (CPZ), a VR-1 antagonist, attenuates dextran sodium sulfate (DSS) colitis in rats. DSS-induced colitis resembles ulcerative colitis with regard to its pathologic features. In this study, we examined the effect of CPZ on trinitrobenzene sulfonic acid (TNBS)-induced colitis, an experimental model of intestinal inflammation that most closely resembles the histologic and microscopic features of Crohn's disease. Colitis was induced by administering a single enema of 100 mg/kg TNBS in 50% ethanol via catheter to lightly anesthetized rats. Subsets of rats were treated with either 1 micromol/kg/ml of CPZ or CPZ-vehicle via enema for 6 days. Seven days after TNBS administration, rats were sacrificed and inflammation was assessed using a validated macroscopic damage score (MDS) and by measuring myeloperoxidase (MPO) activity. In addition, histologic examination was performed. TNBS administration resulted in reproducible chronic erosive lesions extending into the muscularis propria and extensive recruitment of neutrophils in the distal colon. MDS and MPO scores were considerably elevated in the TNBS colons when compared with the TNBS vehicle animals. TNBS rats treated with CPZ enemas exhibited a substantial reduction in MDS and MPO scores and demonstrated dramatically improved pathologic findings. Topical CPZ resulted in considerable attenuation of TNBS-induced colitis. These results support the role of VR-1 and sensory neurons with regard to intestinal inflammation.

Topics: Animals; Capsaicin; Colitis; Colon; Nociceptors; Peroxidase; Rats; Rats, Sprague-Dawley; Receptors, Drug; Trinitrobenzenesulfonic Acid; TRPV Cation Channels

Neurogenic mechanisms have been implicated in the induction of inflammatory bowel disease (IBD). Vanilloid receptor type 1 (TRPV1) has been visualized on nerve terminals of intrinsic and extrinsic afferent neurones innervating the gastrointestinal tract and local administration of a TRPV1 antagonist, capsazepine, reduces the severity of dextran sulphate sodium (DSS)-induced colitis in rats (Gut 2003; 52: 713-9(1)). Our aim was to test whether systemically or orally administered TRPV1 antagonists attenuate experimental colitis induced by 5% DSS in Balb/c mice. Intraperitoneal capsazepine (2.5 mg kg(-1), bid), significantly reduced the overall macroscopic damage severity compared with vehicle-treated animals (80% inhibition, P < 0.05); however, there was no effect on myeloperoxidase (MPO) levels. An experimental TRPV1 antagonist given orally was tested against DSS-induced colitis, and shown to reverse the macroscopic damage score at doses of 0.5 and 5.0 mg kg(-1). Epithelial damage assessed microscopically was significantly reduced. MPO levels were attenuated by approximately 50%, and diarrhoea scores were reduced by as much as 70%. These results suggest that pharmacological modulation of TRPV1 attenuates indices of experimental colitis in mice, and that development of orally active TRPV1 antagonists might have therapeutic potential for the treatment of IBD.

Topics: Animals; Anticoagulants; Capsaicin; Colitis; Dextran Sulfate; Disease Models, Animal; Dose-Response Relationship, Drug; Female; Inflammatory Bowel Diseases; Ion Channels; Mice; Mice, Inbred BALB C; Peroxidase; TRPV Cation Channels

We used the [3H]resiniferatoxin binding assay to demonstrate for the first time the existence of vanilloid receptors in the rat colon and to explore their expression during trinitrobenzene sulfonic acid-induced colitis. Membranes obtained from control colon bound [3H]resiniferatoxin with an affinity of 3 nM; the receptor density was 450 fmol/mg protein or 9 fmol/mg wet weight. Capsaicin and capsazepine, a competitive antagonist of capsaicin, inhibited specific resiniferatoxin binding with Ki values of 3 microM and 0.1 microM, respectively. Trinitrobenzene sulfonic acid induced a very rapid ulceration in the colon: 1 h after treatment 90% of the colon showed ulcerative damage. Coadministration of 640 microM capsaicin diminished the ulcerative effect of trinitrobenzene sulfonic acid to 64% when examined 1 h after trinitrobenzene sulfonic acid challenge; however, this protective action was lost 23 h later. Colon samples obtained 4 h, 24 h, and 1 week after trinitrobenzene sulfonic acid challenge bound resiniferatoxin, capsaicin, and capsazepine with affinities similar to those of control samples. The receptor density remained at an essentially constant level when expressed in fmol/mg protein but, in keeping with the increased wet weights, showed a reduction when expressed in fmol/mg wet weight. We conclude that acute capsaicin administration protects against the ulcerative action of trinitrobenzene sulfonic acid, most likely via the release of protective neuropeptides from capsaicin-sensitive nerve endings. The loss of this protective action is presumably due to a depletion of the protective neuropeptides rather than to a loss of vanilloid (capsaicin) receptors.

Topics: Administration, Topical; Animals; Capsaicin; Colitis; Diterpenes; In Vitro Techniques; Kinetics; Male; Membranes; Rats; Rats, Sprague-Dawley; Receptors, Drug; Trinitrobenzenesulfonic Acid