Ca2+ increase and pH decrease induced by hypochlorous acid in single quiescent myocytes isolated from rat ventricles.
Cytosolic free calcium concentration ([Ca2+]i) and intracellular pH (pHi) were simultaneously measured with a fluorescence technique using fura-2 and BCECF. Hypochlorous acid (HOC1) increased [Ca2+]i and decreased pHi of single quiescent myocytes isolated from rat ventricles. The HOC1-induced changes in [Ca2+]i and pHi (delta [Ca2+]i and delta pHi) were 129 +/- 18nM and 0.18 +/- 0.02 (mean +/- SD), respectively, with 200 microM HOC1. A positive linear correlation was obtained between delta [Ca2+]i and delta pHi under various extracellular Ca2+, pH, and Na+ conditions. Chelation of extracellular Ca2+ depressed only one-fourth of delta [Ca2+]i, and Ca2+ antagonists (verapamil and nifedipine) did not reduce delta [Ca2+]i, indicating that delta [Ca2+]i originates mainly from intracellular Ca2+ stores. A disulfide-reducing reagent, 1,4-dithiothreitol (DTT), recovered the increased [Ca2+]i and decreased pHi to the control levels. The simultaneous changes in [Ca2+]i and pHi induced by HOC1 and the simultaneous restoration of the normal [Ca2+]i and pHi in cardiac myocytes.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002469:Cell Separation; D003600:Cytosol / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D006321:Heart / Q000187:drug effects*; D006352:Heart Ventricles; D006863:Hydrogen-Ion Concentration; D006997:Hypochlorous Acid / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism
D002121:Calcium Channel Blockers; D006997:Hypochlorous Acid; D012964:Sodium; D002118:Calcium; D004229:Dithiothreitol