Ca2+ increase and pH decrease induced by hypochlorous acid in single quiescent myocytes isolated from rat ventricles

Jpn J Physiol. 1995;45(4):619-30. doi: 10.2170/jjphysiol.45.619.


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.

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology
  • Cell Separation
  • Cytosol / metabolism
  • Dithiothreitol / pharmacology
  • Heart / drug effects*
  • Heart Ventricles
  • Hydrogen-Ion Concentration
  • Hypochlorous Acid / pharmacology*
  • Male
  • Myocardium / cytology
  • Myocardium / metabolism*
  • Osmolar Concentration
  • Rats
  • Rats, Sprague-Dawley
  • Sodium / metabolism


  • Calcium Channel Blockers
  • Hypochlorous Acid
  • Sodium
  • Calcium
  • Dithiothreitol