| The Effects of Desflurane on Ca2+ Release from the Myocardial Sarcoplasmic Reticulum in Vitro. |
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Sun Joon Bai, Young Seok Lee, Jae Kwang Shim, Jin Soo Kim, Jin Cheon Moon, Yong Taek Nam |
1Department of Anesthesiology, Yonsei University College of Medicine Seoul.
2Department of Anesthesiology, Ajou University School of Medicine, Suwon, Korea. |
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| Abstract |
BACKGROUND
The purpose of this study is to examine the effect of Desflurane on myocardial contractility and cellular electrophysiologic behabior in isolated guinea pig and rat right ventricular papillary muscle.
METHODS
The isometric force of a guinea pig ventricular papillary muscle was studied in normal and 26 mM Tyrode's solution at various stimulation rates.
Experiments using rat papillary muscles under normal Tyrode's solution at resting-state (RS) and using guinea pig papillary muscles under low Na Tyrode's solution (25 mM) were performed to evaluate the effect on Ca2+ release from the sarcoplasmic reticulum (SR). Normal and slow action potentials (APs) were evaluated by using a conventional microelectrode technique. Effects of desflurane on SR function in situ were examined by its effect on rapid colling contractures (RCCs). 1 MAC (end-tidal concentration: 6%) and 2 MAC desflurane were applied.
RESULTS
Desflurane equivalent to 6% and 12% depressed guinea pig myocardial contractions in the control to -70% and -40% from RS to 3 Hz stimulation rates.
Contractile force after rest in rat and guinea pig myocardium under low Na Tyrode's solution showed modest depression. In the partially depolarized, beta-adrenergically stimulated myocardium, 6% and 12% desflurane caused marked depression of late force (6%: -60%, 12%: -80%) with moderate changes of early peak force (6%: -20%, 12%: -40%). RCCs were abolished at 6% concentration.
CONCLUSIONS
The direct myocardial depressant effects of desflurane is slightly greater to those seen with isoflurane. The rapid initial release of Ca2+ from the SR by depolarization seems to be modestly depressed, although certain release pathways induced by rapid colling appear to be markedly depressed. |
| Key Words:
Anesthetics, volatile; desflurane; Heart: action potential; calcium current; contractility; rapid colling contracture |
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