Angiotensin II modulates cardiac Na+ channels in neonatal rat |
| |
Authors: | J R Moorman G E Kirsch A E Lacerda A M Brown |
| |
Affiliation: | Department of Medicine, University of Texas Medical Branch, Galveston 77550. |
| |
Abstract: | Since chronic congestive heart failure syndromes are associated with both elevated circulating levels of angiotensin II and potentially lethal ventricular tachyarrhythmias, we investigated the effect of angiotensin II on voltage-dependent cardiac Na+ currents. Single-channel Na+ currents in neonatal rat ventricular myocytes were studied using the patch clamp method in the cell-attached mode. Angiotensin II applied outside the patch increased the frequency of opening and rates of activation and inactivation of single-channel Na+ currents within the patch. These effects were mimicked by the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) and were prevented by prior incubation with TPA. Therefore, we propose that angiotensin II modulates cardiac Na+ currents by a cytoplasmic second messenger, perhaps protein kinase C, and this may predispose toward arrhythmia. |
| |
Keywords: | |
|
|