Vasodilatation induced by capsaicin in rat mesenteric vessels is probably independent of nitric oxide synthesis.
Vasal relaxation induced by capsaicin was investigated on perfused mesenteric vascular bed prepared from Wistar rats. Bolus infusion of capsaicin, from 3.5 to 16 nmol, elicited a dose-dependent vasal relaxation effect, which was antagonized by pretreatment with 3 x 10(-6) M calcitonin gene-related peptide (CGRP) (8-37), an antagonist of CGRP. In order to test whether NO-release is involved in vasorelaxant response to capsaicin, a preparation of mesenteric vascular bed was perfused and superfused for 1 h by N omega-nitro-L-arginine methyl ester (L-NAME) (3 x 10(-3) M), an NO-synthase inhibitor. Vasodilatation induced by capsaicin remained unchanged, while that induced by acetylcholine, used as control, was significantly reduced. The results indicate that in the mesenteric bed, capsaicin-induced vasodilatation is probably independent of the NO-synthesis mechanism and possibly mediated by CGRP.
Potenza
M A
MA
Institute of Pharmacology, Medical School, University of Bari, Italy.
De Salvatore
G
G
Montagnani
M
M
Serio
M
M
Mitolo-Chieppa
D
D
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D002211:Capsaicin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase; D051381:Rats; D017208:Rats, Wistar; D013152:Splanchnic Circulation / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects*
D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin; D019331:NG-Nitroarginine Methyl Ester