Cat Heart Muscle In Vitro
Year: 1964
Type: article
Abstract: Cellular concentrations, [K](i), [Na](i), and [Cl](i), and cell water contents were measured in vitro at 27 degrees C in cat papillary muscles. Measurements were made with and without ouabain at varying concentrations of K and ouabain, at pH 5.2 and 9.0, in absence of O(2), and in NaCl-free solution. Large losses of cell K and increases of cell Na occurred in presence of ouabain, at 2-3 degrees C, and in K-free medium. The dependence of inhibition of cation transport by ouabain on external K concentration, studied at constant initial [K](i), was consistent with a competition between K and ouabain localized to the external face of the membrane. In NaCl-free sucrose solution [K](i) remained at its physiological value and was not affected by exposure to ouabain or low temperature, except when Ca was also omitted. Ouabain inhibition persisted at pH 9.0 and in Ca-poor media. Cells swelled and lost K at pH 5.2, and residual ouabain effect was small. At pH 9.0, or in absence of O(2), or in Ca-poor solutions cells became permeable to mannitol. The ion movements observed after inhibition of active transport are compatible either with a passive K distribution and a primary inhibition of Na extrusion or with inhibition of a coupled active transport of both K and Na.
DOI: 10.1085/jgp.47.3.531
Authors: Ernest Page, R. J. Goerke, S. R. Storm
Institution: Harvard University
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1976618877