Propofol is an alternative to thiopental as an intravenous induction agent for cesarean section. It is also used as a sedative for supplementation of regional blockade during cesarean section. It has been reported that propofol relaxes not only vascular smooth muscle but also other smooth muscles. The aim of this study was to investigate the effect of propofol on rat uterine smooth muscle in an isolated preparation in the rat.

Uterine smooth muscle tissues were obtained from rats (n = 21). The muscle strips were suspended in tissue baths and isometric tension was recorded. After spontaneous or oxytocin induced activity had been accomplished in the buffer solution as a control, propofol (1 to 20µg/ml) in fat emulsion was applied cumulatively to the bath and the effects were continuously recorded.

In vitro, propofol induced a dose-dependent inhibition of spontaneous as well as oxytocin induced myometrial contractile activity. Propofol concentration of 1µg/ml had no significant effects on the resting tension, active tention, and frequency of contraction developed by spontaneous and oxytocin induced uterine contractility. However, Complete muscular relaxations on spontaneous and oxytocin induced contractility were obtained at a concentration of 10µg/ml and 20µg/ml, respectively.

Propofol inhibits spontaneous and oxytocin-induced uterine smooth muscle contractions in dose dependent pattern.