The electrophysiologic effects of endothelin. A patch clamp study in guinea pig ventricular myocytes.
To study the electrophysiologic effects of endothelin-1 (ET-1), we used patch clamp and glass microelectrode techniques to investigate the effects of ET-1 on cardiac L-Ica, Ik and Ik2 in guinea pig ventricular myocytes. The prolongation of APD50 was induced and EADs was triggered by 50 nM ET-1 perfusion. L-Ica and Ik were enhanced by various ET-1 concentration from 1 to 50 nM with dose-dependence. Their steady-state activations of L-Ica and Ik shifted left with ET-1 concentration increments. ET-1 elicited a kind of GTP-dependent inward rectifier K+ current having a mean conductance of 82.36 +/- 1.27 pS. The open time and close time (both interburst intervals and burst durations) abbreviated with ET-1 concentration increase. The results suggested that EADs -ET evoked was ascribed to the prolongation on the plateau level, which resulted from L-Ica enhancement. The ET- evoked inward rectifier K+ current should be further studied.
Lu
T
T
Laboratory of Cardiology, First Affiliated Hospital of Suzhou Medical College.
Huang
Y
Y
Jiang
W
W
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D016232:Endothelins / Q000494:pharmacology*; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology; D008839:Microelectrodes; D009206:Myocardium / Q000166:cytology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000187:drug effects
D016232:Endothelins; D015221:Potassium Channels