Alotaibi Mohammed F
Department of Physiology, College of Medicine, King Saud University and King Khalid University Hospital, P.O. Box 2925, Riyadh 11461, Kingdom of Saudi Arabia.
Gen Physiol Biophys. 2017 Jan;36(1):75-82. doi: 10.4149/gpb_2016022. Epub 2016 Oct 27.
Oxytocin (OT) and oxytocin receptors (OTRs) play essential roles in parturition and the effect of OT on uterine contractility is greatly influenced by the expression of OTRs in myometrium. We investigated the effect of OT on uterine strips isolated from non-pregnant, late-pregnant, term-pregnant, and labouring rats and from labouring and non-labouring women. Longitudinal uterine strips (from each gestational stage) were dissected and mounted vertically in an organ bath setup system and challenged with 5 nM OT and the effect was investigated on uterine contractility. In other experiments, phospholipase C (PLC), prostaglandin H synthase-2 (PGHS-2), and calcium-activated chloride channels (CaCCs) were blocked and the effect of OT was tested in labouring rats. OT stimulated the labouring uterus with greater force compared to other gestations in rats and also augmented the uterine force in labouring women compared to the non-labouring. However, blocking the PLC, PGHS-2, and CaCCs significantly reduced the OT-induced force increase in labouring rats. These data suggest that as labour approaches, the sensitivity of the uterine tissues to OT is greatly enhanced concomitant with the increased expression of OTR to ensure strong and adequate uterine contractions essential for the normal delivery and to prevent the postpartum haemorrhage.
催产素（OT）和催产素受体（OTRs）在分娩过程中发挥着重要作用，OT对子宫收缩力的影响很大程度上受子宫肌层中OTRs表达的影响。我们研究了OT对从非妊娠、妊娠晚期、足月妊娠和分娩期大鼠以及分娩和未分娩女性分离出的子宫条的影响。（从每个妊娠阶段）解剖纵向子宫条并垂直安装在器官浴设置系统中，用5 nM OT进行刺激，并研究其对子宫收缩力的影响。在其他实验中，阻断磷脂酶C（PLC）、前列腺素H合酶-2（PGHS-2）和钙激活氯通道（CaCCs），并在分娩期大鼠中测试OT的作用。与大鼠的其他妊娠期相比，OT对分娩期子宫的刺激力更大，与未分娩女性相比，OT也增强了分娩期女性的子宫收缩力。然而，阻断PLC、PGHS-2和CaCCs显著降低了OT诱导的分娩期大鼠子宫收缩力的增加。这些数据表明，随着分娩临近，子宫组织对OT的敏感性大大增强，同时OTRs的表达增加，以确保正常分娩所必需的强烈且充分的子宫收缩，并防止产后出血。
