Calcium concentration during anoxic perfusion modifies post-ischemic hypercontraction in the canine heart.
The purpose of this study was to clarify the role of calcium flux in the pathogenesis of transient overshoot in regional myocardial contractile function after brief ischemia (post-ischemic hypercontraction). Six open-chest anesthetized dogs were examined. The left anterior descending coronary artery (LAD) was cannulated with a bypass system from the left carotid artery. Two minutes of total coronary occlusion of the LAD resulted in a post-ischemic hypercontraction 1 minute after reperfusion. Post-ischemic hypercontraction was abolished after reperfusion following 2 minutes of perfusion with anoxic Krebs-Henseleit solution containing 2.5 mM calcium. Post-ischemic hypercontraction occurred after calcium-free anoxic perfusion. The regional myocardial contractile function remained depressed 1 minute after reperfusion following anoxic perfusion with 5.0 mM calcium solution. Thus, post-ischemic hypercontraction was modified by the calcium concentration during anoxia. Alteration in transsarcolemmal calcium influx during reperfusion, which was modified by alterations in the calcium environment during anoxia, could be responsible for this phenomenon.
Yoshikawa
T
T
Department of Medicine, School of Medicine, Keio University, Tokyo, Japan.
Akaishi
M
M
Ikeda
F
F
Ikegawa
T
T
Handa
S
S
Nakamura
Y
Y
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D015687:Cell Hypoxia / Q000187:drug effects; D004285:Dogs; D005260:Female; D005947:Glucose / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D017202:Myocardial Ischemia / Q000378:metabolism / Q000503:physiopathology*; D015425:Myocardial Reperfusion; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion / Q000379:methods; D014325:Tromethamine / Q000494:pharmacology
C074097:Krebs-Henseleit solution; D014325:Tromethamine; D005947:Glucose; D002118:Calcium