title: A role of ion channels in the endothelium-independent relaxation of rat mesenteric artery induced by resveratrol.
abstract: Recently it has been suggested that resveratrol relaxes different isolated arteries. The present study addressed the question whether different ion channels are involved in the endothelium-independent mechanism of vasodilatation induced by resveratrol. For that purpose, we tested the action of resveratrol on the rat mesenteric artery without endothelium. Resveratrol induced concentration-dependent relaxation of rat mesenteric artery. Among the K(+)-channel blockers, 4-amynopiridine (4-AP) moderately antagonized the resveratrol-induced relaxation, while glibenclamide, tetraethylammonium chloride, charybdotoxin, margatoxin, and barium chloride did not inhibit resveratrol-induced vasorelaxation. In rings, precontracted with 100 mM K(+), the relaxant responses to resveratrol were highly significantly shifted to the right compared to those obtained in rings precontracted with phenylephrine, but resveratrol-induced maximal relaxation was only slightly affected. In order to minimize the influence of K(+) channels and voltage-gated Ca(2+) channels (VGCCs) in vascular smooth muscle, the third contraction was made by 100 mM K(+) in the presence of nifedipine. The relaxant response to resveratrol was abolished. Thus, the mechanism of vasorelaxation induced by resveratrol probably involves activation of 4-AP-sensitive K(+) channels. Its ability to completely relax the mesenteric artery precontracted with K(+)-rich solution suggests that K(+) channel-independent mechanism(s) are involved in its vasorelaxant effect. It seems that interaction with VGCCs plays a part in this K(+) channel-independent effect of resveratrol.
authors.affiliation: Department of Clinical Pharmacology, Pharmacology and Toxicology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia. bukarica@rcub.bg.ac.yu
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Gojkovic-Bukarica
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Novakovic
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kanjuh
authors.forename: Marko
authors.initials: M
authors.lastname: Bumbasirevic
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Lesic
authors.forename: Helmut
authors.initials: H
authors.lastname: Heinle
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects*; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D000077185:Resveratrol; D013267:Stilbenes / Q000494:pharmacology*; D014665:Vasodilator Agents
chemical_list: D002121:Calcium Channel Blockers; D007473:Ion Channels; D026902:Potassium Channel Blockers; D013267:Stilbenes; D014665:Vasodilator Agents; D009543:Nifedipine; D000077185:Resveratrol; D011188:Potassium