抄録
Volatile anesthetics suppress cardiac contractility. On the other hand, volatile anesthetics, isoflurane, sevoflurane and halothane, were reported to enhance the positive inotropic action of β-adrenoceptor stimulation. In this study, these modulations of volatile anesthetics to β-adrenoceptor stimulation were examined by electrophysiological method. L-type Ca2+ channel current (ICa,L) of isolated rabbit ventricular myocytes were measured with the whole-cell configuration of patch clamp technique. The β-adrenoceptor stimulation was induced by 30 nM isoproterenol (ISO). Isoflurane (1.15%), sevoflurane (1.7%) or halothane (0.74%) were bubbled in experimental solution and air was bubbled in control group. Isoflurane, sevoflurane and halothane decreased I Ca,L by 21.3±1.3%, 19.8±2.4%, and 31.7±3.1%, respectively. In control group, ISO increased I Ca,L to 153.0±7.0%. While ISO increased I Ca,L to 241.8±14.9%, 237.2±25.4%, and 247.6±16.3% in the presence of isoflurane, sevoflurane, and halothane respectively. These results show that isoflurane, sevoflurane and halothane enhance the effect of β-adrenoceptor stimulation on I Ca,L. This study suggests that positive inotropic effect of β-adrenoceptor stimulation is enhanced in the presence of volatile anesthetics through increase in ICa,L. [J Physiol Sci. 2007;57 Suppl:S229]
