[Heterogeneity of Na+/Ca2+ exchanger current across the left ventricular wall of rabbit].

Abstract

OBJECTIVE To investigate the distribution characteristics of Na+/Ca2+ exchanger current (I(Na+/Ca2+)) across the left ventricular wall of rabbit and the relationship between I(Na+/Ca2+) and transmural depolarization heterogeneity. METHODS By using whole-cell patch clamp techniques, action potentials (AP), I(Na+/Ca2+), and both rapid and slow components of delayed rectifier potassium current (I(Kr) and I(Ka)) were recorded in subendocardial (Endo), midmyocardial (M), and subepicardial (Epi) cells of the left ventricular wall of rabbit. RESULTS AP duration in M cells was longer than that in Epi cells, P<0.01. At the test potential of +40 mV, outward I(Na+/Ca2+) in M cells was larger than that in Epi and Endo cells, P<0.01, P<0.05, respectively. At the test potential of -100 mV, inward I(Na+/Ca2+) in M cells was larger than that in Epi cells, P<0.05. At the test potential of +50 mV, the tail current density of I(Ka) in M cells was smaller than that in Epi cells, P<0.05, and there was no significant difference among the tail current densities of I(Kr) in Endo, M, and Epi cells. CONCLUSION The distribution of I(Na+/Ca2+) and I(Ka) across the left ventricular wall of rabbit is unequal, which contributes to the transmural depolarization heterogeneity.

Cite this paper

@article{Wang2004HeterogeneityON, title={[Heterogeneity of Na+/Ca2+ exchanger current across the left ventricular wall of rabbit].}, author={Jun-kui Wang and Chang-cong Cui and Xin-Yi Chen and Xiao-wei Yao and Qing-hai Yao and Jiang-fang Lian}, journal={Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition}, year={2004}, volume={35 4}, pages={496-9} }