PI-PLC FUNCTION IN PREGNANT RAT MYOMETRIUM

磷脂酰肌醇特异性磷脂酶C(PI-PLC)起着至关重要的作用 在子宫肌层细胞内信号转导过程中对 子宫紧张性激素(如催产素)。最近的报道证实，派- PLC在开发和维护方面也发挥着重要作用 在许多不同细胞类型中发生的胞浆钙振荡 对激素受体占位的反应。正如在初步讨论中所讨论的 数据，在我的实验室进行的研究提供了令人信服的支持 对于假设t在子宫肌层收缩发生的反应： 催产素刺激胞浆钙振荡。该数据还 提示PI-PLC在生化事件中起重要作用 导致胞浆钙振荡和子宫肌层收缩。 这项申请中提出的研究将检验这一假设 催产素刺激G蛋白/PI-PLC复合体，导致 胞浆钙振荡导致子宫肌层阶段性收缩。 具体目标如下：1)评价强直性子宫收缩的效果 激动剂和PI-PLC抑制剂对细胞内钙振荡和 2)阐明肌醇1，4，5-肌醇的作用。 胞浆钙振荡和时相子宫肌层中的三磷酸 收缩，3)评估钙诱导的钙释放的作用 (CICR)在PI-PLC诱导的钙振荡和时相子宫肌层中的作用 4)评价细胞外钙在心肌缺血过程中的作用。 PLC引起钙振荡和子宫肌层时相性收缩。这个 建议的研究将利用获得的子宫肌层组织进行 从怀孕的Spraogue-Dawley大鼠的特定怀孕日期。这些 研究将首次提供一种细胞内机制 解释催产素刺激如何导致时相的发展 子宫肌层收缩。这些信号转导的特征 子宫肌层的机制将极大地提高我们对 在分娩期间发生的基本机制，并促进 治疗精神障碍的有效药理药物研究进展 劳动(如早产)。

Phosphoinositide-specific phospholipase C (PI-PLC) plays an essential role during intracellular signal transduction in myometrium in response to uterotonic hormones (eg. oxytocin). Recent reports have confirmed that PI- PLC also plays an important role in the development and maintenance of cytosolic calcium oscillations occurring in many different cell types in response to hormone receptor occupancy. As discussed in the preliminary data, studies performed in my laboratory have provided compelling support for the hypothesis t at myometrial contractions occur in response :t,o oxytocin stimulated cytosolic calcium oscillations. This data also suggests that PI-PLC plays an essential role in the biochemical events resulting in cytosolic calcium oscillations and myometrial contractions. The research being proposed in this application will test the hypothesis that oxytocin stimulates the G-protein/PI-PLC complex, resulting in cytosolic calcium oscIllations which drive phasic myometrial contractions. The specific aims are as follows: 1) evaluate the effects of uterotonic agonists and PI-PLC inhibitors on cytosolic calcium oscillations and phasic myometrial contractions, 2) elucidate the role of inositol 1,4,5- trisphosphate during cytosolic calcium oscillations and phasic myometrial contractions, 3) evaluate the role of calcium-induced calcium release (CICR) during PI -PLC induced calcium oscillations and phasic myometrial contractions, and 4) evaluate the role of extracellular calcium during PI- PLC induced calcium oscillations and phasic myometrial contractions. The proposed studies will be performed utilizing myometrial tissue obtained from pregnant Sprague-Dawley rats on specific days of gestation. These studies will provide, for the first time, an intracellular mechanism explaining how oxytocin stimulation results in the development of phasic myometrial contraction.Characterization of these signal transduction mechanisms in myometrium will significantly improve our understanding of basic mechanisms occurring during parturition, and facilitate the development of effective pharmacologic agents to treat disturbances of labor (eg. premature labor).