Shirahase H, Usui H, Shimaji H, Kurahashi K, Fujiwara M
Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
Life Sci. 1991;49(4):273-81. doi: 10.1016/0024-3205(91)90014-3.
Endothelium-dependence of contractile responses to endothelin-1 was examined in isolated canine basilar arteries. Within 2 hrs after mounting tissue preparations, endothelin-1 (10(-9) M) caused a monophasic tonic contraction that developed very slowly and was sustained in intact and endothelium-removed arteries. More than 5 hrs after tissue mounting, endothelin-1 (10(-9) M) caused a biphasic contraction consisting of phasic and tonic components in intact arteries, and caused a monophasic tonic contraction in endothelium-removed arteries. This phasic component was significantly decreased by aspirin (5 x 10(-5) M,), OKY-046 (10(-5) M) (a TXA2 synthetase inhibitor) and ONO-3708 (10(-8) M) (a TXA2 antagonist). The present experiments demonstrate that endothelin-1 causes an endothelium-independent tonic contraction and an endothelium-dependent phasic contraction in canine basilar arteries, and suggest that TXA2 plays a role as an endothelium-derived contracting factor.
在离体犬基底动脉中研究了对内皮素 -1 的收缩反应的内皮依赖性。在安装组织标本后的 2 小时内，内皮素 -1（10⁻⁹ M）引起单相强直性收缩，其发展非常缓慢，并且在完整和去除内皮的动脉中持续存在。组织安装超过 5 小时后，内皮素 -1（10⁻⁹ M）在完整动脉中引起由相性和强直性成分组成的双相收缩，而在去除内皮的动脉中引起单相强直性收缩。阿司匹林（5×10⁻⁵ M）、OKY -046（10⁻⁵ M）（一种血栓素 A2 合成酶抑制剂）和 ONO -3708（10⁻⁸ M）（一种血栓素 A2 拮抗剂）可显著降低这种相性成分。本实验表明，内皮素 -1 在犬基底动脉中引起内皮非依赖性强直性收缩和内皮依赖性相性收缩，并提示血栓素 A2 作为一种内皮源性收缩因子发挥作用。
