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THE EFFECT OF A CHANGE IN SHAPE OF THE CARDIAC ACTION POTENTIAL ON THE IONIC CONDUCTANCES
Author(s) -
Johnson Edward A,
Tille J,
Wilson Lesley
Publication year - 1961
Publication title -
australian journal of experimental biology and medical science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0004-945X
DOI - 10.1038/icb.1961.18
Subject(s) - conductance , ventricular action potential , resting potential , sodium , potassium , sodium channel , stimulus (psychology) , membrane potential , chemistry , time constant , biophysics , electrophysiology , medicine , physics , biology , repolarization , condensed matter physics , psychology , organic chemistry , engineering , electrical engineering , psychotherapist
SUMMARY Rabbit ventricular muscle was stimulated at a low constant rate and an extra stimulus was interposed shortly after every fourth action potential. Pairs of differently shaped action potentials were obtained in this way. The magnitude and time course of polarisation resistance have been determined throughout these action potential pairs. The increase in polarisation resistance during the repolarisation phase was more prolonged and somewhat greater in the action potential of longer duration and area. Changes in membrane conductance to sodium and potassium ions throughout the action potentials have been computed. Throughout the whole of the repolarisation phase the computed potassium conductance is lower and the computed sodium conductance is higher than in the resting state.