CHARACTERIZATION OF RESPONSES TO CROMAKALIM AND PINACIDIL IN SMOOTH AND CARDIAC-MUSCLE BY USE OF SELECTIVE ANTAGONISTS

Abstract

1. In dog isolated coronary artery (precontracted with endothelin, 10 nM) cromakalim (0.1-30 microM) and pinacidil (1-30 microM) produced concentration-dependent vasorelaxant responses. The effects of these compounds could be blocked by glibenclamide (3 microM), phentolamine (30 microM) or alinidine (30 microM) to a similar extent, indicating that both agents alter vascular tone through the same mechanism in this preparation. 2. The ability of the antagonists glibenclamide, phentolamine and alinidine to block the response to cromakalim in a number of smooth muscle types from the guniea-pig was determined. Cromakalim (0.1-30 microM) produced concentration-dependent relaxant responses in thora..