AJP - Heart and Circulatory Physiology, Vol 263, Issue 4 1128-H1136, Copyright © 1992 by American Physiological Society

ARTICLES

Electroporation and recovery of cardiac cell membrane with rectangular voltage pulses

O. Tovar and L. Tung
Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205.

Electroporation of the cardiac cell membrane may result from intense electric fields applied to cardiac muscle, associated for example with defibrillation and cardioversion. We analyzed the distribution of voltage levels sufficient to cause electroporation in enzymatically isolated frog cardiac cells, using the cell-attached patch-clamp technique with rectangular pulses similar to those used in experimental studies of cardiac defibrillation. Five-millisecond monophasic or ten-millisecond biphasic symmetric (1/1) and asymmetric (1/0.5) rectangular pulses of either polarity were applied to the cell membrane in 100-mV steps from 0.2 to 0.8 V. The membrane conductance was continuously monitored by a low-voltage pulse train. In a total of 77 cells, we observed a step increase in conductance, occurring in 21% of cells at a transmembrane potential of 0.3 V, 52% at 0.4 V, 14% at 0.5 V, and 13% at 0.6-0.8 V. Electroporation occurred with this voltage distribution regardless of pulse shape, polarity, or the presence of all of the following ionic channel blockers: tetrodotoxin, barium, tetraethylammonium, 4-aminopyridine, cadmium, nickel, and gadolinium. The time course of membrane recovery was highly variable. The maintenance of a high membrane conductance after the shock pulse was associated with irreversible cell contracture provided that Ca2+ was included in the patch-pipette solution. However, with biphasic asymmetric pulses, the conductance recovered very quickly (< or = 37 ms).(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				Y. Kuramochi, C. C. Lim, X. Guo, W. S. Colucci, R. Liao, and D. B. Sawyer Myocyte contractile activity modulates norepinephrine cytotoxicity and survival effects of neuregulin-1{beta} Am J Physiol Cell Physiol, February 1, 2004; 286(2): C222 - C229. [Abstract] [Full Text]

				V. P. Nikolski, A. T. Sambelashvili, V. I. Krinsky, and I. R. Efimov Effects of electroporation on optically recorded transmembrane potential responses to high-intensity electrical shocks Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H412 - H418. [Abstract] [Full Text] [PDF]

				O. H. Tovar and J. L. Jones Electrophysiological Deterioration During Long-Duration Ventricular Fibrillation Circulation, December 5, 2000; 102(23): 2886 - 2891. [Abstract] [Full Text] [PDF]

				D. K.-L. Cheng, L. Tung, and E. A. Sobie Nonuniform responses of transmembrane potential during electric field stimulation of single cardiac cells Am J Physiol Heart Circ Physiol, July 1, 1999; 277(1): H351 - H362. [Abstract] [Full Text] [PDF]

				M. Neunlist and L. Tung Dose-dependent reduction of cardiac transmembrane potential by high-intensity electrical shocks Am J Physiol Heart Circ Physiol, December 1, 1997; 273(6): H2817 - H2825. [Abstract] [Full Text] [PDF]

				A. M. Gillis, V. G. Fast, S. Rohr, and A. G. Kleber Spatial Changes in Transmembrane Potential During Extracellular Electrical Shocks in Cultured Monolayers of Neonatal Rat Ventricular Myocytes Circ. Res., October 1, 1996; 79(4): 676 - 690. [Abstract] [Full Text]

				V. G. Fast and E. R. Cheek Optical Mapping of Arrhythmias Induced by Strong Electrical Shocks in Myocyte Cultures Circ. Res., April 5, 2002; 90(6): 664 - 670. [Abstract] [Full Text] [PDF]