The effects of inhibition of the sarcolemmal Ca-ATPase on systolic calcium fluxes and intracellular calcium concentration in rat ventricular myocytes - PubMed (original) (raw)

. 1999 May;437(6):966-71.

doi: 10.1007/s004240050868.

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• PMID: 10370076
• DOI: 10.1007/s004240050868

The effects of inhibition of the sarcolemmal Ca-ATPase on systolic calcium fluxes and intracellular calcium concentration in rat ventricular myocytes

H S Choi et al. Pflugers Arch. 1999 May.

Abstract

The effects of carboxyeosin, an inhibitor of the sarcolemmal Ca-ATPase, were studied on intracellular Ca and membrane currents in isolated rat ventricular myocytes. In the absence of carboxyeosin, 150-ms-duration depolarizing pulses from -40 to 0 mV resulted in an L-type Ca current on depolarization and a Na-Ca exchange "tail" current on repolarization. The calculated entry of Ca on the L-type current was 1.3 times greater than the efflux via the Na-Ca exchange. The addition of carboxyeosin (20 microM) resulted in either an increase of the Na-Ca exchange current or a decrease of the L-type Ca current such that the Ca entry and efflux were exactly equal. These results suggest that, under control conditions, a carboxyeosin-sensitive Ca-ATPase contributes about 24% of the total Ca efflux from the cell and, therefore, that the sarcolemmal Ca-ATPase has a significant role in regulation of sarcolemmal Ca fluxes.

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