INFLUENCES OF CHRONIC SMOKING AND ALCOHOL COMSUMPTION ON OXYTOCIN- AND DILTIAZEM-INDUCED FUNCTIONAL RESPONSES OF PREGNANT RAT MYOMETRIUM KRONİK SİGARA VE ALKOL MARUZİYETİNİN GEBE RAT MİYOMETRİYUM OKSİTOSİN- VE DİLTİAZEM-ARACILI FONKSİYONEL YANITLARI ÜZERİNE ETKİLERİ

Objective: Smoking and alcohol consumption during pregnancy lead to undesired effects on labor. Although the underlying mechanisms are still poorly understood, impaired functional responses of myometrium may be one of the reasons for these complications. In this study, we investigated the effects of chronic smoking and alcohol consumption on the functional responses of isolated term-pregnant rat myometrium strips. Methods: 21 Wistar albino rats were divided into three groups: Control; Smoking group, rats exposed to smoke for 12 weeks; Alcohol group, rats were administered ethanol for 12 weeks (n=7 in each group). The reactivities of myometrial smooth muscle strips obtained from term labor rats were mounted in organ chambers for the recording of isometric tension. The effects of cumulative concentrations of carbachol (10-10 M), oxytocin (10-10 M), and diltiazem (10-10 M) on myometrial spontaneous contractions were measured. Results: The amplitude and frequency of carbachol contractile responses decreased in the alcohol group, whereas it significantly increased in the smoking group. The frequency of oxytocin-induced myometrial contractions was significantly increased by smoking, while the amplitude of contractions was not changed. Oxytocin responses as amplitude and frequency of contractions decreased in the alcohol group. There were no significant differences between relaxant responses to diltiazem in both group compared to the controls. Conclusion: These findings show that smoking may lead to premature labor and alcohol consumption may prolong gestation length by changing contractile and relaxant responses in myometrial smooth muscle. Diltiazem may have a beneficial effect on tocolysis in both conditions during