Ion currents, action potentials, and noradrenergic responses in rat pulmonary vein and left atrial cardiomyocytes

Effects of noradrenaline on action potential (AP) repolarisation in PV cardiomyocytes. A Representative AP recording from a PV cardiomyocyte in control solution and in the presence of 1  μM noradrenaline (NA). B Representative AP recording from another PV cardiomyocyte in control solution and in the presence of 1 μM NA showing lack of AP prolongation. C Before‐and‐after plot of APD30 in PV cardiomyocytes in control solution and after superfusion with 1  μM NA. D Noradrenaline‐induced fold‐changes in APD30 in LA and PV cardiomyocytes. AbstractThe electrophysiological properties of pulmonary vein (PV) ‐cardiomyocytes, and their responses to the sympathetic neurotransmitter, noradrenaline (NA), are thought to differ from those of the left atrium (LA) and contribute to atrial ectopy. The aim of this study was to examine rat PV cardiomyocyte electrophysiology and responses to NA in comparison with LA cells. LA and PV cardiomyocytes were isolated from adult male Wistar rat hearts, and membrane potentials and ion currents recorded at 36°C using whole‐cell patch‐clamp techniques. PV and LA cardiomyocytes did not differ in size. In control, there were no differences between the two cell‐t ypes in zero‐current potential or action potential duration (APD) at 1 Hz, although the incidence of early afterdepolarizations (EADs) was greater in PV than LA cardiomyocytes. The L‐type Ca2+ current (ICaL) was ~ ×1.5 smaller (p = .0029, Student'st test) and the steady...
Source: Physiological Reports - Category: Physiology Authors: Tags: ORIGINAL RESEARCH Source Type: research