The comparison of the relaxant effects of propofol, thiopental, ketamine, and etomidate on isolated rat uterine smooth muscle. |
Sam Sung Eun, Tae Hun An, Ki Tae Jung, Jong Dal Jung, Keum Young So, Byung Sik Yu, Kyung Joon Lim, Sang Hun Kim, Hyun Young Lee, Chang Hoon Song, Honglin Shi, Ji Lin |
1Eun Sam Sung Plastic and Reconstructive Hospital, Bu-Cheon, Korea. than@chosun.ac.kr 2Department of Anesthesiology and Pain Medicine, College of Medicine, Chosun University, Gwangju, Korea. 3Department of Obestetrics and Gynecology, College of Medicine, Chosun University, Gwangju, Korea. 4JB Stem Cell Institute, Inc., Gwangju, Korea. 5Department of Anesthesiology, Yanjishiyiyuan Hospital, Jilinsheng, China. |
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Abstract |
BACKGROUND Intravenous hypnotics are used in pregnancy, labor and delivery. The aim of the present study was to investigate and compare the relaxant effects of propofol, thiopental, ketamine, and etomidate on isolated rat uterine smooth muscles. METHODS Uterine smooth muscle preparations were obtained from non-pregnant female rats. The uterus of the rat was dissected and cut into 10 mm strips. The muscle strips were bathed in Krebs solution. After spontaneous uterine contractile activity had been accomplished, propofol, ketamine, thiopental, and etomidate in various concentrations were added cumulatively to the baths and resting tension, active tension, and frequency of contration were recorded at each concentration of agents. EC(5), EC(25), EC(50), EC(75), and EC(95) of each drug on active tension and frequency of contraction were calculated using a probit model. RESULTS Propofol, thiopental, and etomidate reduced uterine contractions in a concentration-dependent manner. Ketamine concentrations of 10(-7) to 10(-5) M augmented uterine contractions but ketamine concentrations of 10(-4) to 10(-3) M attenuated uterine contractions. The EC(50)'s of propofol, thiopental, ketamine, and etomidate on active tension were 1.56 x 10(-5) M, 4.97 x 10(-5) M, 3.52 x 10(-4) M, and 2.73 x 10(-5) M, respectively. CONCLUSIONS All four intravenous hypnotics relaxed the uterine smooth muscle of rats except for ketamine in low concentrations (10(-7) to 10(-5) M). Propofol had the greatest relaxant effects on isolated rat uterine smooth muscle among these hypnotics. It seems that ketamine is a suitable obstetric hypnotic agent for hypovolemic parturients and propofol is a useful hypnotic agent for uterine relaxation during pregnancy. |
Key Words:
etomidate; hypnotics; ketamine; propofol; rat uterine smooth muscle; thiopental |
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