| Abstrakt: |
In ventricular trabeculae from guinea pig and cat heart superfused with a modified Tyrode's solution (pH=7.4) containing either 137 mM or 103 mM Cl, intracellular pH (pH) was measured with H-sensitive double-barreled microelectrodes. In quiescent preparations pH was 7.26±0.017 when Cl was 137 mM, and 7.38±0.02 in 103 mM chloride. In 103 mM Cl containing saline stimulation of the preparation produced no acidification but in 137 mM Cl acidification occurred. The acidification was completely revesible when chloride was reduced again. When HCO/Cl exchange was blocked by 0.5 mM SITS, pH was lowered similar to the effect of increasing extracellular chloride concentration. It was concluded that when Cl is raised, the HCO/Cl exchanger operates as a Cl/Cl exchanger. [ABSTRACT FROM AUTHOR] |
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