Endothelium is involved in the vasorelaxation by an ATP-sensitive K+ channel opener, NIP-121

Possible involvement of endothelium was examined in the vasorelaxation of r at aorta in response to NIP-121 ((+)-7,8-dihydro-6,6-dimethyl-7-hyroxy-8-(2 -oxo- 1-piperidinyl)-6H-pyrano[2,3-f]benz-2,1,3-oxadiazole), an ATP-sensiti ve K+ (K-ATP) channel opener. The NIP-121-induced vasorelaxation was greate r in endothelium-intact preparations than in endothelium-denuded ones. In t he presence of glibenclamide, which inhibits K-ATP channels, NIP-121-induce d vasorelaxations were of a similar extent in both endothelium-intact and - denuded preparations. These findings suggest that the presence of endotheli um plays a role in the vasorelaxation in response to K-ATP channel openers. (C) 1999 Elsevier Science B.V. All rights reserved.