LIPID & PROTEIN PO4 TURNOVER IN IRIS OF THE EYE

脂质体

• 批准号: 3484003
• 负责人: ATA A ABDEL-LATIF
• 金额: $ 17.46万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1981
• 资助国家: 美国
• 起止时间: 1981-09-30 至 1994-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3484003
• 关键词: G protein; adenylate cyclase; adrenergic agents; antiadrenergic agents; anticholinergic agent; calcium; calcium flux; cholinergic agents; chromatography; cow; cyclic AMP; diacylglycerols; drug metabolism; electrophoresis; extraocular muscle; eye pharmacology; hydrolysis; hypersensitivity desensitization; inositol phosphates; iris; laboratory rabbit; membrane lipids; membrane structure; muscle contraction; muscle relaxation; muscle tension; myosins; phosphatidylinositols; phospholipids; phosphoproteins; phosphorylation; prostaglandins; protein kinase C; radioassay; receptor; second messengers; smooth muscle; swine; uvea ciliary body

The overall goals of this research proposal are: (a) to investigate the role of phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis and its derived second messengers in agonist-induced muscle contraction in the sphincter and dilator smooth muscles of the iris-ciliary body, (b) to seek novel interactions between the cAMP and IP3-DG-CA2+ second messenger systems and the tension responses in these muscles, and (c) to investigate the involvement of PIP2 hydrolysis and its derived second messengers in the mechanism of receptor desensitization in the smooth muscles of the iris. Specifically: (I) To understand the biochemical-functional interactions between IP3-Ca2+-DG and cAMP signalling pathways in the smooth muscles of the iris-ciliary body we will: 1. Investigate the relationships between PG-induced IP3 accumulation, DG production, MLC phosphorylation, cAMP formation and muscle tension in the iris sphincter of different species. 2. Investigate the relationships between the effects of various agonists and antagonists, including adrenergic, muscarinic cholinergic, peptidergic and PGs, on the biochemical and functional responses in the bovine sphincter and dilator muscles. 3. Investigate the interaction between the PIP2 pathway and the adenylate cyclase pathway that is mediated through the activation of protein kinase C. 4. Investigate the effects of cAMP and/or its analogues on agonist- induced IP3 accumulation in iris sphincter membrane fractions. (11) To elucidate the role of PIP2 hydrolysis in the molecular mechanisms underlying receptor desensitization of the smooth muscles of the rabbit and bovine iris-ciliary body we will: (1) Investigate alterations in receptor-induced IP3 accumulation, DG production, MLC phosphorylation, cAMP formation and contraction due to in vitro and/or in vivo cholinergic, adrenergic, peptidergic and PG desensitization. 2. Investigate the possibility that protein kinase C-mediated phosphorylation of G proteins and/or receptors could be involved in the mechanism of desensitization. 3. Investigate the possibility that in vivo cholinergic and adrenergic desensitization of the eye may be reversed by administration of myo- inositol. 4. Characterize, through binding studies, the IP3 receptors in the iris muscle membranes and investigate the properties of IP3-induced Ca2+ fluxes in membrane fractions from normal and desensitized muscle. (III) We will investigate the role of MLC phosphatase in the mechanism of agonist-induced muscle relaxation in the iris sphincter. (IV) We will isolate and characterize the smooth muscle cells of the iris sphincter and dilator and investigate the properties of receptor-mediated PIP2 hydrolysis, Ca2+ mobilization, MLC phosphorylation and cAMP formation. Interaction between the cAMP and IP3-CA2+-DG signalling systems represent an important focal point for pharmacological manipulation and the proposed studies will lead to better understanding of aqueous humor dynamics and to the development of more effective and antiglaucoma drugs. In addition, our proposed studies will yield important information on: (a) Properties and function of muscarinic, alpha1-adrenergic, PG and peptidergic receptors in the anterior segment; (b) mechanisms of receptor desensitization in ocular tissues; (c) mechanisms of action of pharmacological agents in the eye; and (d) mechanistic insights into the role of PIP2 and its derived second messengers in smooth muscle function.

本研究建议的总体目标是：（a）调查 磷脂酰肌醇4，5-二磷酸（PIP2）水解的作用及其 在激动剂诱导的肌肉收缩中衍生的第二信使 虹膜睫状体的括约肌和扩张平滑肌，（B）寻找 cAMP与IP3-DG-CA 2+第二信使的新型相互作用 系统和这些肌肉的张力反应，以及（c）调查 PIP2水解及其衍生的第二信使参与 受体脱敏的机制在平滑肌的 爱瑞丝 具体而言：（一）了解生物化学功能 IP3-Ca2 +-DG和cAMP信号通路之间的相互作用 虹膜睫状体的平滑肌，我们将：1.探讨 PG诱导的IP3积累、DG产生、MLC 虹膜括约肌中的磷酸化、cAMP形成和肌张力 不同的物种。2. 研究了 各种激动剂和拮抗剂，包括肾上腺素能的， 毒蕈碱胆碱能，肽能和PG，对生化和 牛括约肌和扩张肌的功能反应。 3. 研究PIP2通路和腺苷酸之间的相互作用 通过激活蛋白激酶介导的环化酶途径 C. 4.研究cAMP和/或其类似物对激动剂- 诱导IP3在虹膜括约肌膜组分中积累。 (11)到 阐明PIP2水解在分子机制中的作用 家兔平滑肌的潜在受体脱敏 和牛虹膜睫状体，我们将：（1）调查改变， 受体诱导的IP3积累，DG产生，MLC磷酸化， 由于体外和/或体内胆碱能的cAMP形成和收缩， 肾上腺素能、肽能和PG脱敏。 2.探讨 蛋白激酶C介导的G蛋白磷酸化 和/或受体可能参与脱敏机制。 3.研究体内胆碱能和肾上腺素能 眼睛的脱敏可以通过施用肌钙蛋白来逆转。 肌醇。 4.通过结合研究，表征 虹膜肌膜，并研究IP3诱导的 正常和脱敏肌肉膜组分中的Ca2+通量。 (III)我们将研究MLC磷酸酶在细胞凋亡机制中的作用。 激动剂引起的虹膜括约肌肌肉松弛。 (IV)我们将 分离并表征虹膜括约肌的平滑肌细胞， 扩张剂，并研究受体介导的PIP2的性质 水解、Ca2+动员、MLC磷酸化和cAMP形成。 cAMP和IP3-CA 2 +-DG信号系统之间的相互作用代表了 药理学操作的一个重要焦点， 研究将导致更好地了解房水动力学， 开发更有效的抗青光眼药物。 此外，本发明还提供了一种方法， 我们建议的研究将产生以下重要信息：（a）性能 以及毒蕈碱、α 1-肾上腺素能、PG和肽能的功能 （B）受体的机制 脱敏在眼组织;（c）的作用机制 药物在眼睛;和（d）机械的见解， PIP2及其衍生的第二信使在平滑肌功能中的作用。