Myocardial recovery during post-ischemic reperfusion: optimal concentrations of Na+ and Ca2+ in the reperfusate and protective effects of amiloride added to cardioplegic solution.
The effects of Na+ and Ca2+ concentrations in the reperfusate on post-ischemic myocardial recovery were examined. Also, the myocardial protective effects of amiloride, an inhibitor of the Na+/Ca2+ and Na+/H+ exchange systems, added to cardioplegic solutions were assessed, using an isolated working rat heart perfusion system. Global myocardial ischemia was induced by 30-min normothermic cardioplegic arrest, using St. Thomas' solution. The concentration of Na+ in the reperfusate varied, stepwise, from 75 to 145 mM/l, and that of Ca2+, from 0.1 to 2.5 mM/l. In this study post-ischemic functional recovery was best at 110mM/l Na+ and 1.2-1.8 mM/l Ca2+ in the reperfusate. A significantly greater post-ischemic functional recovery and a lower creatine kinase release were observed when amiloride was added to the cardioplegic solution. Ca2+ overload via Na+/Ca2+ and Na+/H+ exchange systems would, thus, appear to be due, at least in part, to post-ischemic reperfusion injury.
Yamada
T
T
Department of Cardiovascular Surgery, Nagasaki University School of Medicine, Japan.
Takagi
M
M
Kugimiya
T
T
Miyagawa
N
N
Shibata
R
R
Hashiyada
H
H
Yamaguchi
H
H
D000584:Amiloride / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006439:Hemodynamics / Q000502:physiology; D017136:Ion Transport; D008297:Male; D015425:Myocardial Reperfusion / Q000379:methods*; D015428:Myocardial Reperfusion Injury / Q000209:etiology / Q000517:prevention & control; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000378:metabolism
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002314:Cardioplegic Solutions; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D000584:Amiloride; D012964:Sodium; D002118:Calcium