Spontaneous motility of the cervix in cyclic and ovariectomized ewes and changes induced by exogenous hormones.

Continuous recordings of the electrical and mechanical activities of the cervix were made. Two basic patterns of electrical signal, short spike bursts and long spike bursts, showed close mechanical relationships with the record of mechanical activity. Electrical activity was organized in myoelectrical complexes including the regular alternation of phases of irregular spiking activity and phases of regular spiking activity. The myoelectrical complexes of the cervix existed independently of the sexual status although the frequency of recurrence did vary. The highest frequency was recorded during the periovulatory period around oestrus when each complex was synchronized with a similar pattern recorded from the uterine horns. At the end of the periovulatory period, the irregular spiking activity decreased, the myoelectrical complex pattern of the cervix and uterine horns consisting mainly of regular spiking activity at a high frequency until metoestrus. During the luteal phase, only the cervix remained active, with myoelectrical complexes formed mainly by phases of regular spiking activity recurring at long intervals. This pattern was also recorded after ovariectomy in the absence of hormonal treatment.