Objective: To investigate the correlation of myoelectrical signals with spontaneous contractile events and physiological states in the nonisolated uterine horn of rats.
Design: In vivo uterine myoelectrical activity recording study.
Setting: Animal and pharmacology laboratory at Inonu University.
Animal(s): Thirty-six female Wistar albino rats.
Intervention(s): Six animals were not castrated and served as a sham-operated control group; the other 30 were ovariectomized (OVX) and put into groups: unbiased OVX subjects, estrogen (E)-biased OVX subjects, P-biased OVX subjects, E-plus-P-biased OVX subjects, and hCG-biased OVX subjects. An MP100 A-CE was used for data acquisition, and a personal computer was used for processing.
Main Outcome Measure(s): Besides the temporal, spectral, and joint time-frequency (spectrotemporal) analysis, some quantitative measures such as standard deviation and mark to space power I ratios of myoelectrical signals were measured.
Result(s): Progesterone, E, and hCG administration down-regulated the power and contraction frequency of the uterine electrical signal. The spectral concentrations that occurred around the 0.9, 0.35, and 0.7 Hz frequency ranges may be distinguishing characteristics for P, E, and hCG, respectively.
Conclusion(S): Based on the obtained results, uterine contractions change with ovariectomy and administration of hormones. Progesterone, E, and hCG particularly prolong the quiescent periods of the uterus by reducing the frequency of uterine contractions as well as the power of the myoelectrical activity. Individual or combined use of R. or hCG might favor quiescence of the uterine muscle and the maintenance of pregnancy.