Myocardial acidosis, as during ischemia, profoundly modifies excitation-contraction mechanisms. The decreased myofilament sensitivity to Ca2+ reduces contractility regardless of an intracellular accumulation of Ca2+. To determine the source for this increase in Ca2+ we evaluated the effect of acidosis on diastolic [Ca2+] and mitochondrial [Ca2+]. We used single cardiac cells loaded with the fluorescent probes, indo-1 for Ca2+ and SNARF-1 for pH. Acidosis increases [Ca2+] both in cytosol and mitochondria. The cytosolic accumulation depends, most likely, on an active release from mitochondria. A competition among Ca2+ and H+ ions may, instead, explains the increase in mitochondrial [Ca2+].
|Translated title of the contribution||[Autom. eng. transl.] [Acidosis is associated with an intracellular accumulation of Ca2+. Its role in the modulation of myocardial contractility]|
|Number of pages||3|
|Publication status||Published - 1992|
- Fluorescent Dyes
- Hydrogen-Ion Concentration
- Mitochondria, Heart
- Myocardial Contraction