Bkaily G, Wang S, Bui M, Ménard D
Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Québec, Canada.
J Cardiovasc Pharmacol. 1995;26 Suppl 3:S293-6.
Using the whole-cell voltage-clamp technique, endothelin (ET-1) was found to stimulate T- and L-type Ca2+ currents in a dose-dependent manner in both human and chick ventricular single cells. However, ET-1 had no effect on both the fast sodium current and the delayed outward K+ current in these cells. The effect of ET-1 on both Ca2+ currents was blocked by the ET(A) receptor antagonist BQ123. Treatment of single ventricular cells with pertussis toxin (PTX) prevented stimulation of T- and L-type calcium currents by ET-1. These results suggest that there are functional ET(A) receptors in both human and chick ventricular cells. The stimulation of both types of Ca2+ currents appears to be mediated by a PTX-sensitive G-protein.
采用全细胞膜片钳技术发现，内皮素（ET-1）在人和鸡心室单细胞中以剂量依赖方式刺激T型和L型Ca2+电流。然而，ET-1对这些细胞中的快钠电流和延迟外向K+电流均无影响。ET-1对两种Ca2+电流的作用被ET(A)受体拮抗剂BQ123阻断。用百日咳毒素（PTX）处理单个心室细胞可阻止ET-1对T型和L型钙电流的刺激。这些结果表明，人和鸡心室细胞中均存在功能性ET(A)受体。两种类型Ca2+电流的刺激似乎是由PTX敏感的G蛋白介导的。
