title: A comparison of the relaxant effects of pinacidil in rabbit renal and mesenteric artery.
abstract: 1. The relaxant effects of pinacidil were compared in isolated rabbit renal and mesenteric artery. 2. Pinacidil (10 nm-300 microM) relaxed renal and mesenteric arterial rings precontracted with phenylephrine with pD2 values of 5.11 +/- 0.03 and 6.27 +/- 0.04, respectively. 3. The inhibitory effect of pinacidil on the rabbit mesenteric artery was competitively antagonized by glibenclamide (1-10 microM). The calculated pKB value was 6.37 +/- 0.04. On the renal artery, glibenclamide (2-20 microM) did not significantly affect pinacidil-induced relaxation (P > 0.05). 4. Tetraethylammonium (TEA, 1-10 mM) competitively antagonized the pincaidil induced relaxation of the rabbit renal artery. The pKB value was 3.22 +/- 0.08. On the mesenteric artery TEA antagonized the effect of pinacidil in a noncompetitive manner. 5. The concentration-response curves for pinacidil on the rabbit renal and mesenteric artery were not affected by apamin (0.1 microM). 6. It is concluded that ATP-sensitive K+ channels (KATP) are not involved in pinacidil action on the rabbit renal artery. On the contrary, KATP are probably major sites of pinacidil action on the rabbit mesenteric artery.
authors.affiliation: Department of Pharmacology, Medical Faculty, Belgrade, Yugoslavia.
authors.forename: L
authors.initials: L
authors.lastname: Gojković
authors.forename: T
authors.initials: T
authors.lastname: Kazić
mesh_terms: D000818:Animals; D001030:Apamin / Q000494:pharmacology; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects*; D020110:Pinacidil; D015221:Potassium Channels / Q000502:physiology*; D011817:Rabbits; D012077:Renal Artery / Q000187:drug effects*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D006146:Guanidines; D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D014665:Vasodilator Agents; D001030:Apamin; D020110:Pinacidil; D005905:Glyburide