PHASE RESETTING OF EMBRYONIC CHICK ATRIAL HEART CELL AGGREGATES - EXPERIMENT AND THEORY

被引:18
作者
CLAY, JR [1 ]
BROCHU, RM [1 ]
SHRIER, A [1 ]
机构
[1] MCGILL UNIV,DEPT PHYSIOL,MONTREAL H3G 1Y6,QUEBEC,CANADA
基金
英国医学研究理事会;
关键词
D O I
10.1016/S0006-3495(90)82404-8
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The influence of brief duration current pulses on the spontaneous electrical activity of embryonic chick atrial heart cell aggregates was investigated experimentally and theoretically. A pulse could either delay or advance the time of the action potential subsequent to the pulse depending upon the time in the control cycle at which it was applied. The perturbed cycle length throughout the transition from delay to advance was a continuous function of the time of the pulse for small pulse amplitudes, but was discontinuous for larger pulse amplitudes. Similar results were obtained using a model of the ionic currents which underlie spontaneous activity in these preparations. The primary ion current components which contribute to phase resetting are the fast inward sodium ion current, INa, and the primary, potassium ion repolarization current, IX1. The origin of the discontinuity in phase resetting of the model can be elucidated by a detailed examination of the current-voltage trajectories in the region of the phase response curve where the discontinuity occurs. © 1990, The Biophysical Society. All rights reserved.
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页码:609 / 621
页数:13
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