Comparative studies on the calcium paradox in cardiac muscle: the effect of temperature on the different phases.
By measuring characteristic ultrastructural damage, the Ca2+-paradox has been demonstrated in isolated frog hearts, and in frog and mouse ventricle strips. During Ca2+-free perfusion (phase I), PCa of the sarcolemma is increased; 4 degrees C provides complete protection against these molecular changes in frog and a partial protection in mouse tissue. Re-introduction of extracellular Ca2+ (phase II) now causes typical Ca2+-triggered damage which is markedly reduced at 4 degrees C in both species but is not inhibited by leupeptin. Major sarcolemma damage occurs at this point.
D000818:Animals; D002118:Calcium / Q000502:physiology*; D007976:Leupeptins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D009200:Myocardial Contraction; D009206:Myocardium / Q000648:ultrastructure; D010477:Perfusion; D011896:Rana temporaria; D013696:Temperature
D007976:Leupeptins; C032854:leupeptin; D002118:Calcium