| Autor: |
Wolska, B., Lewartowski, B. |
| Zdroj: |
Basic Research in Cardiology; Nov1990, Vol. 85 Issue 6, p585-594, 10p |
| Abstrakt: |
We investigated the net transsarcolemmal Ca shifts and Ca/Ca exchange by means ofCa in isolated, perfused ventricles of guinea pig heart treated with vanadate to inhibit ATP-driven sarcolemmal Ca pump. The heart was stimulated (at the rate of 60/min) and perfused with a solution containingCa for 60 min. Thereafter stimulation was stopped and either perfusion with radioactive solution was continued or the solution was exchanged for a non-radioactive one. In the first case, tissueCa content (equivalent to the exchangeable Ca content) dropped from 1.960±0.120 mmol/kg of wet weight (w.w.) to 0.715±0.049 mmol/kg w.w. and stabilized at this level between 5th and 10th min. In the second case, decrease inCa content continued and within 40 min attained 0.047±0.004 mmol/kg w.w., despite stabilizing of the total exchangeable Ca content. Drop ofCa content in the rested heart perfused (until the end of experiments) with radioactive solution resulted from the net transsarcolemmal Ca shift and it was strongly inhibited by removal of extracellular Na. The continuing drop inCa content in the heart perfused with non-radioactive solution while total Ca content stabilized must have resulted from Ca/Ca exchange; it was stimulated by removal of extracellular Na. These experiments separate two modes ofCa fluxes and suggest that a common route of these fluxes is the Na/Ca exchanger. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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