Effects of endothelin-1 on calcium and potassium currents in undiseased human ventricular myocytes

Magyar, János and Iost, Norbert and Körtvély, Á. and Bányász, Tamás and Virág, László and Szigligeti, P. and Varró, András and Opincariu, M. and Szécsi, J. and Papp, Julius Gyula and Nánási, P. P. (2000) Effects of endothelin-1 on calcium and potassium currents in undiseased human ventricular myocytes. Pflugers Archiv - European Journal of Physiology, 441 (1). pp. 144-149. ISSN 0031-6768 (print), 1432-2013 (online)

[img] Text
Restricted to Registered users only

Download (76kB) | Request a copy


Endothelins have been reported to exert a wide range of electrophysiological effects in mammalian cardiac cells. These results are controversial and human data are not available. Our aim was to study the effects of endothelin-l (ET-1, 8 nmol/l) on the L-type calcium current (ICa-L) and various potassium currents (rapid component of the delayed rectifier, I-Kr; transient outward current, I-to; and the inward rectifier K current, I-K1) in isolated human ventricular cardiomyocytes. Cells were obtained from undiseased donor hearts using collagenase digestion via the segment perfusion technique. The whole-cell configuration of the patch-clamp technique was applied to measure ionic currents at 37 degreesC. ET-1 significantly decreased peak I-Ca,I-L from 10.2+/-0.6 to 6.8+/-0.8 pA/pF at +5 mV (66.7% of control, P <0.05, n=5). This reduction of peak current was accompanied by a lengthening of inactivation. The voltage dependence of steady-state activation and inactivation was not altered by ET-1. I-Kr, measured as tail current amplitudes at -40 mV, decreased from 0.31+/-0.02 to 0.06+/-0.02 pA/pF (20.3% of control, P <0.05, n=4) after exposure to ET-1. ET-I failed to change the peak amplitude of I-to, measured at +50 mV (9.3+/-4.6 and 9.0+/-4.4 pA/pF before and after ET-1, respectively), or steady-state I-K1 amplitude, measured at the end of a 400-ms hyperpolarization to -100 mV (3.6+/-1.4 and 3.7+/-1.4 pA/pF, n=4). The present results indicate that in undiseased human ventricular myocytes ET-1 inhibits both ICa-L and I-Kr; however, the degree of suppression of the two currents is different.

Item Type: Article
Subjects: Q Science / természettudomány > QP Physiology / élettan
Depositing User: Erika Bilicsi
Date Deposited: 12 Mar 2013 12:42
Last Modified: 12 Mar 2013 12:42

Actions (login required)

Edit Item Edit Item