The effect of hypothermia during the period of calcium repletion on the calcium paradox.
Reperfusion of an isolated heart with a calcium-containing solution after a short calcium-free perfusion may result in irreversible cell damage: the calcium paradox. In this investigation the effect of hypothermia during reperfusion with calcium-containing solution on the calcium paradox damage in the isolated rat heart was studied. In addition, the effect of pre-cooling the heart during the calcium-free period was investigated. Creatine kinase release was used to define cell damage. Normothermic (37 degrees C) calcium-free perfusion followed by normothermic reperfusion with calcium-containing solution resulted in a massive release of CK. When the normothermic calcium-free perfusion was followed by hypothermic (10 degrees C) calcium-containing reperfusion, CK release was reduced by 20% (P less than 0.005). This CK release during reperfusion was further reduced by 55% and 80% when the normothermic calcium-free perfusion was followed by 5 or 10 min respectively of hypothermic calcium-free perfusion prior to the hypothermic calcium-containing reperfusion. The results show that hypothermia during the period of calcium repletion retards the sequence of events which ultimately results in release of large amounts of intracellular components.
D000818:Animals; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D003402:Creatine Kinase / Q000032:analysis; D006321:Heart / Q000187:drug effects*; D007036:Hypothermia, Induced; D008297:Male; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D012508:Sarcolemma / Q000378:metabolism; D013997:Time Factors
D003402:Creatine Kinase; D002118:Calcium