[Effects of neurotransmitters on the spontaneous activity of the mouse uterine in situ at various stages of pregnancy].

Serotonin, acetylcholine and noradrenaline neither initiated nor indicated the uterus contractility in immature or pregnant mice; they, however, regulated the uterine motility in respect to the neurotransmitters concentration and the hormonal status of females. Inactivation of the beta-receptors in longitudinal muscle fibres prevented the drop in the myometric contraction force, whereas blockade of the alpha-receptors in circular muscle fibres prevented the reduction of the myometric tone induced by noradrenaline. The data obtained suggests that the circular muscle is responsible for the myometric tone while the longitudinal muscle is responsible for the uterus contraction force.