The regularizing effect of some active substances upon uterine smooth muscle contractile activity.

Our study concentrated upon the modifications of some parameters which characterize uterine smooth muscle contractile activity under the action of active substances. We studied the isotonic contractions of the uterine smooth muscle in a classical organ bath in which we introduced some contracting and relaxing substances. At the beginning, we introduced Oxytocin to determine uterine smooth muscle contractions. After that, we added relaxing substances (Papaverin, Diazepam, Terbutalin, Isoxuprin, Hexoprenalin) in the organ bath, and then, in another protocol, we added combinations of two relaxing substances. We determined for each wave some parameters: minimum, mean, maximum and net amplitude, wave area and duration, the interval between waves, the time while the curve increases from the minimal value of the amplitude to the maximum value, the frequency of contractile waves. For each parameter we determined the variance coefficient (C.V. %), which reflects the regularity of the uterine activity. We observed a regularizing effect of the uterine activity after administration of some active substances. The smallest variance coefficient (C.V. %) was found for HEXO + PAP combination (mean value for C.V. % is 4.71%).