Inhibitory Actions of Endothelial Products on Mechanical and Calcium Responses in Aortic Smooth Muscle Cells

概要

論文の詳細を見る
The effects of endothelial products on intracellular calcium ion concentrations ([Ca^<2+>]_i) were investigated in the guinea-pig aorta. The perfusate of bradykinin-stimulated cultured endothelial cells relaxed aortic rings by 〜70% ; it was reduced to 〜50% by nitroarginine, to 〜30% in high-K solution and remained unalterbd by indomethacin. The perfusate elevated the cyclic GMP content in the muscle, which was inhibited by nitroarginine. In cultured aortic muscle cells, bradykinin elevated [Ca^<2+>]_i with an initial transient and following sustained phase ; the former was absent after treatment with cyclopiazonic acid while the latter was abolished in [Ca^<2+>]_o-free medium. The perfusate lowered aortic [Ca^<2+>]_i, and this action was weakened by nitroarginine and diminished in high-K solution. Therefore, the perfusate reduced aortic [Ca^<2+>]_i with and without an increase in cyclic GMP production. These actions were sensitive to nitroarginine and high-K, respectively, suggesting that the perfusate contained at Ieast two relaxants, EDRF and EDHF, with both lowering [Ca^<2+>]_i in aortic muscle mainly by inhibiting Ca^<2+> influx.
日本平滑筋学会の論文