Calcium paradox in guinea-pig ventricular myocytes.
Measurement of the release of lactate dehydrogenase (LDH), the development of contracture and the exclusion of the dye Trypan Blue were made in isolated guinea-pig ventricular myocytes subjected to conditions that evoke a calcium paradox in intact heart. Incubation at 25 degrees C reduced the release of LDH associated with mechanical manipulation of the myocytes so that during prolonged incubation in media free of Ca2+ and Mg2+ ions at 25 degrees C little release of LDH occurred. A significant release of LDH into the incubation media was provoked on repletion of the divalent cations. This release was accompanied by a marked decrease in the percentage of rod-shaped myocytes and their ability to exclude Trypan Blue. The results provide evidence for the existence of the calcium paradox in isolated guinea-pig ventricular myocytes as originally defined.
Suleiman
M S
MS
University Department of Cardiac Surgery, Bristol Royal Infirmary, UK. M.S.Suleiman@bristol.ac.uk
Edmond
J J
JJ
Bulstrode
G K
GK
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D048429:Cell Size / Q000187:drug effects; D004396:Coloring Agents; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000502:physiology; D006352:Heart Ventricles / Q000187:drug effects; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D010477:Perfusion; D014343:Trypan Blue; D016276:Ventricular Function; D017725:Ventricular Pressure / Q000187:drug effects
D004396:Coloring Agents; D007770:L-Lactate Dehydrogenase; D014343:Trypan Blue; D008274:Magnesium; D002118:Calcium