| Affiliation: | (1) Department of Physiology, Academic Medical Center, Meibergdreef 15, 1105 Amsterdam, The Netherlands;(2) Experimental and Molecular Cardiology Group, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands |
| Abstract: | The presence and functional role of the swelling-activated Cl- current (ICl(swell)) in rabbit cardiac Purkinje cells was examined using patch-clamp methodology. Extracellular hypotonicity (210 or 135 mOsm) activated an outwardly rectifying, time-independent current with a reversal potential close to the calculated Cl- equilibrium potential (ECl). The magnitude of this current was related to tonicity of the superfusate. The current was blocked by 0.5 mM 4,4 -diisothiocyanostilbene-2,2-disulfonic acid (DIDS). These features are comparable to those of ICl(swell) found in sinoatrial nodal, atrial, and ventricular myocytes. ICl(swell) activation at 210 and 135 mOsm depolarized the resting membrane potential with 6 and 10 mV and shortened the action potential by  18 and 33%, respectively. DIDS partially reversed ICl(swell)-induced action potential changes. We conclude that ICl(swell) is present in Purkinje cells and its activation leads to action potential shortening and resting membrane potential depolarization, both of which can promote the development of reentrant arrhythmias.Received 20 January 2004; received after revision 17 February 2004; accepted 25 February 2004 |
