Myocardial recovery during post-ischemic reperfusion: optimal concentrations of Na+ and Ca2+ in the reperfusate and protective effects of amiloride added to cardioplegic solution

• Published in: Heart and vessels Vol. 10; no. 6; pp. 310 - 317
• Main Authors: Yamada, T, Takagi, M, Kugimiya, T, Miyagawa, N, Shibata, R, Hashiyada, H, Yamaguchi, H
• Format: Journal Article
• Language: English
• Published: Japan 01-01-1995
• Subjects: Amiloride - pharmacology; Animals; Calcium - antagonists & inhibitors; Calcium - pharmacology; Calcium Channel Blockers - pharmacology; Calcium Channels - metabolism; Cardioplegic Solutions - pharmacology; Dose-Response Relationship, Drug; Hemodynamics - physiology; Ion Transport; Male; Myocardial Reperfusion - methods; Myocardial Reperfusion Injury - etiology; Myocardial Reperfusion Injury - prevention & control; Myocardium - metabolism; Rats; Rats, Wistar; Sodium - antagonists & inhibitors; Sodium - pharmacology; Sodium Channel Blockers; Sodium Channels - metabolism
• ISSN: 0910-8327; 1615-2573
• DOI: 10.1007/BF02911389

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.