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Science 30 January 1981:
Vol. 211. no. 4481, pp. 485 - 487
DOI: 10.1126/science.7455687
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Articles

Science, Vol 211, Issue 4481, 485-487
Copyright © 1981 by American Association for the Advancement of Science

articles

Potassium chloride versus voltage clamp contractures in ventricular muscle

M Morad, S Reeck, and M Rao

In frog ventricle, developed tension was markedly larger in response to depolarization caused by a voltage clamp step than to depolarization induced by high concentrations of potassium chloride. Measurement of extracellular potassium activity at the surface and at the depth of muscle during the development of contractures showed that the diffusion of potassium is much slower than the spread of depolarization through the cross section of muscle. These two observations suggest that competition between the depolarizing and the negative inotropic effects of an increase in the extracellular potassium ion concentration may determine the time course and magnitude of contractile tension in heart muscle.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Optical measurements of extracellular calcium depletion during a single heartbeat.
L Cleemann, G Pizarro, and M Morad (1984)
Science 226, 174-177
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