THE DEGREE OF MYOMETRIAL STRETCH IS AN IMPORTANT REGULATOR OF UTERINE CONTRACTILE ACTIVITY
Objective. To investigate the impact of stretch on the contractile activity of isolated myometrial specimens from women during pregnancy and non-pregnancy. Material and methods. Isolated myometrial specimens (S) obtained at cesarean section from the women during normal (Group 1) and powerless (Group 2) labor and non-labor (Group 3) were used to study the impact of the mechanical stretch (Str) of the specimens on spontaneous contraction rate, tonic and phasic contraction amplitude, and contractile activity interval. Results. Stepwise Str caused an increase in the rate of spontaneous contractions (C), the amplitude of phasic Cs, and the interval of contractility in all the groups, which was most pronounced in Group 1. With higher Str, the majority of Group 2 specimens showed a considerable abnormality in the relaxation phase of phasic C. Whether stretch-activated TRPC proteins play a role in different myometrial contractility reactions to Str during normal and abnormal labor and non-labor is discussed.