FUNCTION OF GUT PEPTIDES IN ISOLATED GUT MUSCLE CELLS

肠肽在分离的肠肌细胞中的功能

• 批准号: 3228716
• 负责人: GABRIEL M. MAKHLOUF
• 金额: $ 14.38万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-04-01 至 1994-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3228716
• 关键词: Anura; adenosine triphosphate; binding proteins; biological signal transduction; bombesin; calcium; calcium binding protein; calcium channel; calcium flux; calmodulin; calmodulin dependent protein kinase; cholecystokinin; cyclic AMP; cyclic GMP; cyclic nucleoside monophosphate; cytoplasm; dogs; enkephalins; gallbladder; gastrins; gastrointestinal hormones; guinea pigs; human tissue; inositol phosphates; intestines; ion transport; ionomycin; ionophores; isoproterenol; kinins; laboratory rat; lanthanum; membrane lipids; membrane permeability; muscle cells; muscle contraction; muscle proteins; muscle relaxation; myosins; naloxone; neuropeptide receptor; neurotransmitters; opiate alkaloid; opioid receptor; peptide hormone; peptides; pertussis toxin; phenothiazines; phosphodiesterases; phosphorylation; physical chemical interaction; potassium channel; radionuclides; radiotracer; receptor binding; smooth muscle; stoichiometry; stomach; substance P; tachykinin; vasoactive intestinal peptide

The aim of this proposal is to characterize receptors for neuropeptides on muscle cells from human and guinea pig stomach and biliary tract, and to identify the signal transduction pathways to which the receptors are coupled. Cells from different regions of these organs will be examined to determine the existence of functional gradients intrinsic to muscle cells. The emphasis will be on characterization of receptor types for contractile neuropeptides of the tachykinin, opioid and bombesin families and for relaxant neuropeptides of the VIP/PHI family. Characterization will be facilitated by two new approaches: the first enables protection of specific receptor types with selective ligands resulting in enrichment of muscle cells from scarce human tissue and from discrete segments of the stomach and biliary tract. Substantial progress has been made in identifying the transduction pathways for contraction and relaxation: cytosolic free Ca2+ ([Ca2+]i), measured for the first time in human and guinea pig gastric muscle cells, was shown to be stoichiometrically related to net Ca2+ efflux and contraction; inositol 1,4,5-triphosphate (IP3) was shown to cause contraction and Ca2+ release from the intracellular pool used by agonists; and cAMP-dependent relaxation was shown to involve two Ca2+-dependent mechanisms. Studies on contractile neuropeptides will now focus on the kinetics and stoichiometry of membrane phophoinositides, mainly IP3 and its metabolic products, IP4, and their relation to Ca2+ release and uptake and myosin light chain phosphorylation. Studies on relaxation neuropeptides will focus on the mode of action of cAMP in relation to [Ca2+]i and myosin light chain phosphorylation. The properties of two myenteric neuropeptides, somatostatin and galanin, which have no direct contractile or relaxant effects, but which are coupled to modulatory pathways that converge on intracellular Ca2+, will be explored. Somatostatin was shown to inhibit VIP-induced relaxation via coupling to Gi, and galanin to augment relaxation hyperpolarization and opening of K+ channels. A dual coupling of opioid peptides to stimulation of [Ca2+]i and to inhibition of cAMP was also shown. The physiological importance of these novel modulatory and interactive pathways is underlined by the co-localization of VIP, galanin and opioid peptides in a majority of myenteric neurons supplying smooth muscle.

该建议的目的是表征神经肽的受体 来自人类和豚鼠胃和胆道的肌肉细胞，以及 确定受体所处的信号转导途径 耦合。 这些器官不同区域的细胞将检查到 确定肌肉细胞固有的功能梯度的存在。 重点是收缩的受体类型的表征 旋转金，阿片类药物和孟买家庭的神经肽以及 VIP/PHI家族的松弛神经肽。 表征将是 通过两种新方法促进：第一个可以保护 具有选择性配体的特定受体类型，导致富集 来自稀缺人体组织的肌肉细胞和来自离散段的肌肉细胞 胃和胆道。 在识别转导途径方面取得了重大进展 用于收缩和放松：测量的胞质免费Ca2+（[Ca2+] I） 在人和豚鼠胃肌细胞中，第一次显示 与净Ca2+外排和收缩相关； 肌醇1,4,5-三磷酸（IP3）被证明引起收缩，Ca2+ 从激动剂使用的细胞内池释放；依赖营地 松弛显示涉及两个Ca2+依赖性机制。 研究 收缩神经肽现在将重点放在动力学和化学计量上 膜苯肌醇，主要是IP3及其代谢产品IP4， 以及它们与Ca2+释放和吸收和肌球蛋白轻链的关系 磷酸化。 关于放松神经肽的研究将集中于 与[Ca2+] I和肌球蛋白轻链有关的营地的作用方式 磷酸化。 两种肌植物神经肽的特性，生长抑素和加拉宁， 没有直接的收缩或放松效果，但耦合 对于在细胞内Ca2+上收敛的调节途径将是 探索。 生长抑素显示可通过 耦合到gi，加拉宁增强了松弛超极化和 开放K+通道。 阿片类肽与刺激的双重耦合 还显示了[Ca2+] I和抑制营地的属性。 生理 这些新型调制和互动途径的重要性是强调的 通过大多数VIP，Galanin和阿片类肽的共定位 骨膜神经元提供平滑肌。