In-vivo Electrical Stimulation of Uterine Smooth Muscles in Sheep

An animal model was established for invivo studies of the EMG responses of a parturient uterine smooth muscle tissue to electrical stimuli. Five normally gravid sheep were fitted with implanted electrodes to register EMG signals and electrical stimulation. EMG signals were detected at the cervix and at the gravid horn. Spontaneous EMG activity was registered simultaneously with EMG responses to electrical stimulation. Different electrical stimulation parameters and protocols were tested. Direct EMG responses to electrical stimuli detected at the stimulation site were hindered by long lasting artifacts. No significant changes in the EMG activity at the horn were registered due to excitation at the distant cervical region and vice-versa. EMG responses registered during control measurements following each electrical stimulation session show an increase in the EMG signal amplitude (RMS) and a change in the signal frequency contents (increased MF and shift in PDS).