The effects of etomidate on the contraction of pregnant rat uterine smooth muscle / 대한마취과학회지

ABSTRACT

BACKGROUND: It has been reported that etomidate has the relaxant effects on vascular, tracheal, and non-pregnant uterine smooth muscle in vitro. The purpose of this study was to investigate the relaxant effects of etomidate on the contraction of the pregnant rat uterine smooth muscle. METHODS: Uterine muscle tissues were obtained from pregnant rats (n = 15). The uterine segments were mounted in organ baths filled with Krebs solution. After oxytocin-induced contractile activity had been established, etomidate in incremental concentrations (10(-7) to 10(-3) M) was added cumulatively to the bath, each administered 20 min apart, and resultant changes in contractile activity were continuously recorded. EC5 (effective concentration of 5% reduction), EC25, EC50, EC75, and EC95 on active tension were calculated using a probit model. RESULTS: Etomidate (10(-7) to 10(-3) M) induced dose-dependent decreases in amplitude and frequency of uterine contraction. The EC50 of etomidate on active tension were 5.91 x 10(-5) M. CONCLUSIONS: These results demonstrate that etomidate had inhibitory effects on pregnant rat uterine muscle at supraclinical concentration (5.91 x 10(-5) M).