Effects of chloride channel blockers on the contractile and relaxative responses in rat aorta rings / 中国药理学通报

ABSTRACT

AIM To study the effects of DIDS and furosemide on the contraction induced by phenylephrine and the endothelium-dependent relexation induced by ATP. METHODS Measurement of isometric force of rat thoracic aortae rings with and without endothelium. RESULTS DIDS(1～300 ?mol?L -1 ) and furosemide(10～320 ?mol?L -1 ) inhibited the contractile response induced by phenylephrine in a concentration-dependent manner. The inhibitory rate was different between aortic ring endothelium-intact and that endothelium-denuded. The values of IC_ 50 for DIDS were (12.0?8.0) ?mol?L -1 and (28.3?7.3) ?mol?L -1 respectively,while the values of IC_ 50 for furosemide were (17.9?6.6) ?mol?L -1 and (41.0?15.6) ?mol?L -1 respectively. DIDS(10 ?mol?L -1 ) did not chang ATP-induced vasodilative effect at the concentrations of 10 ?mol?L -1 and 100 ?mol?L -1 , but enhanced the relaxation induced by 1 mmol?L -1 ATP. Furosemide (20 ?mol?L -1 ) had no effect on the relaxation induced by ATP(10 ?mol?L -1 ), but prolonged the relaxation when the concentration of ATP added to 100 ?mol?L -1 and 1 mmol?L -1 ( P