内皮素1对豚鼠心室肌细胞正常和急性缺血状态L型钙通道电流的影响

Effects of Endothelin-1 on L-type Calcium Current in Guinea Pig Ventricular Myocytes during Acute Ischemia

目的 探讨内皮素 1(ET- 1)对正常和急性缺血状态下豚鼠心室肌细胞 L型钙通道电流 (ICa- L)的影响。 方法 应用全细胞膜片钳技术记录豚鼠心室肌细胞单一 ICa- L。 结果 5 ,10 ,5 0 nm ol/ L的 ET- 1分别使正常状态心室肌细胞 ICa- L的峰值明显增加 (均 P<0 .0 5 ) ;但在模拟缺血低氧条件下 ET- 1对 ICa- L的峰值和最大激活电位无明显影响。 结论 ET- 1对正常豚鼠心室肌细胞 ICa- L有明显的浓度依赖性增强作用 ;在急性缺血条件下该增强作用消失。

Objective\ To investigate the effects of endothelin\|1(ET\|1) on the L\|type Ca\+\{2+\} channel current(I\-\{Ca\|L\}).\ Methods\ Using the whole cell patch clamp technique in isolated guinea pig ventricular myocytes during both normal Tyrode solution and imitative ischemic condition.\ Results\ In normal Tyrode solution, the application of ET\|1(5, 10, 50 nmol/L) increased obviously the peaks of I\-\{Ca\|L\} by 25 55%±3 65%, 44 98%±1 68% and 72 0%±45 5% compared with the controlled group(P<0 05, respectively).\ But ET\|1 did not produce notable changes on I\-\{Ca\|L\} under imitative acute ischemia.\ There was no any significant changes on maximum active voltage and I\-\{Ca\|L\} I\|V relationship curve.\ Conclusion\ The results suggest that the ET\|1 has a remarkable enhancement on I\-\{Ca\|L\} in isolated guinea ventricular myocytes under normal Tyrode solution, and do not show obvious changes on I\-\{Ca\|L\} under imitative acute ischemia.\;