Effects of Na+ and Ca2+ concentration in cardioplegic and reperfusion solutions on the intracellular Ca2+ of cardiac muscle cells.
10.3349/ymj.1993.34.2.133
- Author:
Myung Jin KIM
1
;
So Ra PARK
;
Chang Kook SUH
Author Information
1. Department of Physiology, Inha University College of Medicine, Inchon, Korea.
- Publication Type:Original Article
- Keywords:
Cardioplegia;
guinea pig;
ion selective microelectrode;
intracellular Na+ activity;
intracellular Ca2+ activity;
Na+-Ca2+ exchange
- MeSH:
Animal;
Calcium/*pharmacology;
Cardioplegic Solutions/*pharmacology;
Ions;
*Myocardial Reperfusion;
Osmolar Concentration;
Papillary Muscles/cytology/*drug effects;
Sodium/*pharmacology;
Solutions/pharmacology
- From:Yonsei Medical Journal
1993;34(2):133-144
- CountryRepublic of Korea
- Language:English
-
Abstract:
The removal of Ca2+ from the cardioplegic solutions could cause the danger of inducing a "calcium paradox" during reperfusion. Since intracellular Ca2+ activities are coupled to Na+ activities via Na(+)-Ca2+ exchange, an increase in intracellular Na+ activities during the cardioplegia could cause an abrupt Ca2+ influx when reperfused. To study the effects of Na+ and Ca2+ concentrations in cardioplegic solutions on intracellular Ca2+ activities during the cardioplegia and subsequent recovery period, the membrane potential and intracellular Na+ and Ca2+ activities of guinea pig ventricular papillary were measured. 1) A cardioplegia with low Ca2+ cardioplegic solution significantly decreased the overshoot and duration of the first action potential after cardioplegia, but the changes in action potential configuration were minimized after a cardioplegia with Ca2+ concentration adjusted according to the Na(+)-Ca2+ exchange mechanism. 2) Intracellular Na+ activity was continuously decreased during the cardioplegia, and the intracellular Na+ activity 20 minutes after cardioplegia was the highest with low Ca2+ cardioplegic solution. 3) Intracellular Na+ and Ca2+ activities were continuously decreased during the cardioplegia with Ca2+ concentration adjusted according to the Na(+)-Ca2+ exchange mechanism. 4) During a reperfusion of Tyrode solution after cardioplegia intracellular Na+ and Ca2+ activities were increased. Intracellular Ca2+ activity was increased more rapidly than intracellular Na+ activity. 5) The rate of increase in intracellular Ca2+ activity with reperfusion of Tyrode solution was dependent upon intracellular Na+ activity during cardioplegia, in such a way that the higher the intracellular Na+ activity was, the faster the intracellular Ca2+ activity increased. These data suggest that Na(+)-Ca2+ exchange mechanism may play an important role in the regulation of intracellular Ca2+ activity during recovery after cardioplegia.
