Investigation of intracellular Ca^<2+> level on uterine contraction in preterm labor

点击翻译按钮获取中文摘要

<AIM> It is suggested that there is a strong association between systemic and intrauterine infection and preterm labor. The mechanisms responsible for the initiation of parturition under these circumstances have still not been completely established. In this study, pregnant Wistar rats on day 17 of gestation were sacrificed 3 hours after intraperitoneal injection of lipopolysaccharide (LPS) or vehicle. The effects of LPS was studied on IP_3 production, intracellular Ca^<2+> level and spontaneous contractions by oxytocin (OXT) of isolated uterine strips from preterm pregnant rats.<RESULTS> 1. OXT significantly increased IP_3 production in both vehicle and LPS-treated rat uteri. The IP_3 production was significantly increased approximately 2 times by LPS treatment compared to control.2. (1) OXT stimulated uterine contraction and intracellular Ca^<2+> level in pregnant rat uterus. However, in Ca^<2+>-free medium, OXT increased uterine contraction but not intracellular Ca^<2+> level. (2) OXT stimulated uterine contraction and intracellular Ca^<2+> level in LPS-treated pregnant rat uterus.<CONCLUSIONS> 1. OXT increases IP_3 production in pregnant rat uterus. It was suggested that the mechanism of uterine contraction by OXT might be involved in Ca^<2+>-independent contraction. 2. LPS enhances IP_3 production by OXT in pregnant rat uterus. However, it is still unknown that LPS also enhances increasing intracellular Ca^<2+> level by OXT.