Increase in coronary blood flow produced by nicorandil is due to K-channel opening mechanism

• Published in: Japanese Journal of Pharmacology 1990, Vol.52 (suppl-1.1), p.81-81
• Main Authors: Yoneyama, Fumiya, Satoh, Keisuke, Taira, Norio
• Format: Article
• Language: English
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1016/S0021-5198(19)55069-7

We have hypothesized that the mechanism of action of nicorandil in increasing coronary blood flow is due to its action as a potassium (K) channel opener. In order to test this hypothesis we investigated whether the effects of nicorandil and cromakalim, a specific K-channel opener, were likewise antagonized by glibenclamide, a pharmacological antagonist of K-channel openers. In isolated, blood-perfused papillary muscle preparations of dogs, intraarterial injections of nicorandil and cromakalim increased (coronary) blood flow. Dose-response curves for increase in coronary blood flow produced by nicorandil or cromakalim were shifted to the right in a parallel way to similar extents by glibenclamide given intravenously to support dogs. Schild analysis yielded pA_2 values of 6.08 and 6.34 for glibenclamide against nicorandil and cromakalim, respectively. These results support our hypothesis that the effect of nicorandil in increasing coronary blood flow is predominantly due to its mechanism of action as a K-channel opener.