Effect of acidosis on Ca2+ sensitivity of skinned cardiac muscle with troponin C exchange Implications for myocardial ischemia
- 13 March 1989
- journal article
- research article
- Published by Wiley in FEBS Letters
- Vol. 245 (1-2), 279-282
- https://doi.org/10.1016/0014-5793(89)80237-6
Abstract
By using a novel approach for the study of the effects of pH variation in skinned myocardium, the present experiments were aimed to provide new insights into the mechanism of ischemia. Ca2+ sensitivity is decreased by acid pH, but the effect is more than double in cardiac myofilaments than that in fast-twitch skeletal muscle fibers. With the technique of troponin C exchange in myocytes, we find here that the effect of pH is the same with cardiac or skeletal troponin C. These results rule out a direct H+-Ca2+ competition on the Ca2+-binding sites of troponin C as a significant mechanism of ischemia. The findings provide conclusive evidence in favor of the idea that acidosis modulates the protein-protein interactions in the regulatory complex in cardiac muscle.Keywords
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