Vasodilatation of canine cerebral arteries by nicorandil, pinacidil and lemakalim.
1. Nicorandil, pinacidil and lemakalim relaxed precontracted rings of canine cerebral artery. 2. The order of potency was lemakalim greater than nicorandil approximately equal to pinacidil, but all these agents were less effective than nimodipine. 3. The effects of nicorandil were inhibited by methylene blue but not by glibenclamide, while the effects of pinacidil and lemakalim were inhibited by glibenclamide but not by methylene blue. 4. Thus nicorandil probably causes relaxation mostly by effects on guanylate cyclase while lemakalim and pinacidil produce the same effect by action at ATP-dependent potassium channels.
Department of Surgery, University of Alberta, Edmonton, Canada.
H
H
Zhang
N
N
Stockbridge
B
B
Weir
B
B
Vollrath
D
D
Cook
D000818:Animals; D001488:Basilar Artery / Q000187:drug effects; D001578:Benzopyrans / Q000494:pharmacology; D002536:Cerebral Arteries / Q000187:drug effects*; D019806:Cromakalim; D004285:Dogs; D005260:Female; D005905:Glyburide / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D066298:In Vitro Techniques; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009536:Niacinamide / Q000031:analogs & derivatives / Q000494:pharmacology; D020108:Nicorandil; D020110:Pinacidil; D015221:Potassium Channels / Q000187:drug effects*; D011758:Pyrroles / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D001578:Benzopyrans; D006146:Guanidines; D015221:Potassium Channels; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; D009536:Niacinamide; D020108:Nicorandil; D020110:Pinacidil; D006162:Guanylate Cyclase; D005905:Glyburide; D008751:Methylene Blue