Tags

Type your tag names separated by a space and hit enter

Dexamethasone prevents visceral hyperalgesia but not colonic permeability increase induced by luminal protease-activated receptor-2 agonist in rats.
Gut 2007; 56(8):1072-8Gut

Abstract

BACKGROUND

Low-grade inflammation may play a role in the pathogenesis of irritable bowel syndrome (IBS). Although corticosteroids are potent inhibitors of inflammatory processes, only one study with corticosteroids in patients with postinfectious IBS exists, which suggests that prednisolone is not an effective treatment for IBS symptoms.

AIM

To evaluate whether dexamethasone treatment prevents protease-activated receptor-2 (PAR-2) activation-induced visceral hyperalgesia and increased permeability in rats, and to determine whether the effects involve colonic mast cells.

METHODS

Abdominal contractions provoked by rectal distension were recorded in rats equipped with intramuscular electrodes. Changes in visceral hypersensitivity provoked by intracolonic administration of PAR-2-activating peptide (SLIGRL; H-serine-leucine-isoleucine-glycine-arginine-leucine-OH), changes in colonic mucosal rat mast cell protease-II (RMCP-II) content, mast cell count and PAR-2 expression were measured after a 4-day treatment with dexamethasone (1 mg/day/rat intraperitoneally) or its vehicle (water). The effect of mast cell stabiliser (doxantrazole, 1 mg/kg intraperitoneally, 2 h before and 6 h after intracolonic infusion of SLIGRL) on SLIGRL-induced visceral hyperalgesia was also assessed. The effects of SLIGRL and a mast cell degranulator (compound 48/80) on the permeability of colonic strips from vehicle- or dexamethasone-treated rats were investigated in Ussing chambers.

RESULTS

4 days of dexamethasone as well as doxantrazole diminished the SLIGRL-induced hyperalgesia for all volumes of distension. This effect of dexamethasone was accompanied by a reduced responsiveness of colonic permeability to compound 48/80, and decreased RMCP-II content and mast cell number. Dexamethasone treatment did not influence colonic mucosal PAR-2 expression and permeability responsiveness to SLIGRL.

CONCLUSIONS

Dexamethasone treatment improves PAR-2 agonist-induced visceral hypersensitivity but does not prevent PAR-2 agonist-induced increase in colonic permeability in rats. This effect is coupled with a reduction of colonic mast cell number and RMCP-II contents.

Authors+Show Affiliations

INRA Neuro-Gastroenterology & Nutrition Unit, 180 Chemin de Tournefeuille, BP 3, 31931 Toulouse Cedex 9, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17309885

Citation

Róka, Richard, et al. "Dexamethasone Prevents Visceral Hyperalgesia but Not Colonic Permeability Increase Induced By Luminal Protease-activated Receptor-2 Agonist in Rats." Gut, vol. 56, no. 8, 2007, pp. 1072-8.
Róka R, Ait-Belgnaoui A, Salvador-Cartier C, et al. Dexamethasone prevents visceral hyperalgesia but not colonic permeability increase induced by luminal protease-activated receptor-2 agonist in rats. Gut. 2007;56(8):1072-8.
Róka, R., Ait-Belgnaoui, A., Salvador-Cartier, C., Garcia-Villar, R., Fioramonti, J., Eutamène, H., & Bueno, L. (2007). Dexamethasone prevents visceral hyperalgesia but not colonic permeability increase induced by luminal protease-activated receptor-2 agonist in rats. Gut, 56(8), pp. 1072-8.
Róka R, et al. Dexamethasone Prevents Visceral Hyperalgesia but Not Colonic Permeability Increase Induced By Luminal Protease-activated Receptor-2 Agonist in Rats. Gut. 2007;56(8):1072-8. PubMed PMID: 17309885.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Dexamethasone prevents visceral hyperalgesia but not colonic permeability increase induced by luminal protease-activated receptor-2 agonist in rats. AU - Róka,Richard, AU - Ait-Belgnaoui,Afifa, AU - Salvador-Cartier,Christel, AU - Garcia-Villar,Raphael, AU - Fioramonti,Jean, AU - Eutamène,Hélène, AU - Bueno,Lionel, Y1 - 2007/02/19/ PY - 2007/2/21/pubmed PY - 2007/8/7/medline PY - 2007/2/21/entrez SP - 1072 EP - 8 JF - Gut JO - Gut VL - 56 IS - 8 N2 - BACKGROUND: Low-grade inflammation may play a role in the pathogenesis of irritable bowel syndrome (IBS). Although corticosteroids are potent inhibitors of inflammatory processes, only one study with corticosteroids in patients with postinfectious IBS exists, which suggests that prednisolone is not an effective treatment for IBS symptoms. AIM: To evaluate whether dexamethasone treatment prevents protease-activated receptor-2 (PAR-2) activation-induced visceral hyperalgesia and increased permeability in rats, and to determine whether the effects involve colonic mast cells. METHODS: Abdominal contractions provoked by rectal distension were recorded in rats equipped with intramuscular electrodes. Changes in visceral hypersensitivity provoked by intracolonic administration of PAR-2-activating peptide (SLIGRL; H-serine-leucine-isoleucine-glycine-arginine-leucine-OH), changes in colonic mucosal rat mast cell protease-II (RMCP-II) content, mast cell count and PAR-2 expression were measured after a 4-day treatment with dexamethasone (1 mg/day/rat intraperitoneally) or its vehicle (water). The effect of mast cell stabiliser (doxantrazole, 1 mg/kg intraperitoneally, 2 h before and 6 h after intracolonic infusion of SLIGRL) on SLIGRL-induced visceral hyperalgesia was also assessed. The effects of SLIGRL and a mast cell degranulator (compound 48/80) on the permeability of colonic strips from vehicle- or dexamethasone-treated rats were investigated in Ussing chambers. RESULTS: 4 days of dexamethasone as well as doxantrazole diminished the SLIGRL-induced hyperalgesia for all volumes of distension. This effect of dexamethasone was accompanied by a reduced responsiveness of colonic permeability to compound 48/80, and decreased RMCP-II content and mast cell number. Dexamethasone treatment did not influence colonic mucosal PAR-2 expression and permeability responsiveness to SLIGRL. CONCLUSIONS: Dexamethasone treatment improves PAR-2 agonist-induced visceral hypersensitivity but does not prevent PAR-2 agonist-induced increase in colonic permeability in rats. This effect is coupled with a reduction of colonic mast cell number and RMCP-II contents. SN - 0017-5749 UR - https://www.unboundmedicine.com/medline/citation/17309885/Dexamethasone_prevents_visceral_hyperalgesia_but_not_colonic_permeability_increase_induced_by_luminal_protease_activated_receptor_2_agonist_in_rats_ L2 - http://gut.bmj.com/cgi/pmidlookup?view=long&pmid=17309885 DB - PRIME DP - Unbound Medicine ER -