Electrical and Pharmacological Properties of Freshly Isolated Single Smooth Muscle Cells

新鲜分离的单个平滑肌细胞的电学和药理学特性

• 批准号: 8819750
• 负责人: Joshua Singer
• 金额: $ 17.88万
• 依托单位: University of Massachusetts Medical School
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-03-01 至 1992-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8819750&HistoricalAwards=false
• 关键词: Electrical; Pharmacological; Properties; Freshly; Isolated

The long term goals of this research program are to understand the function of ionic channels in the membrane of smooth muscle cells and their regulation by transmitters, ions, metabolites, second messengers, and membrane potential. Since ionic channels control the membrane potential, serve as one of the principal targets of neurotronsmitters and second messenger mechanisms, underlie the action potential, and govern calcium entry into the cell, they play a central role in the regulation of smooth muscle contraction. The experiments employ freshly dissociated cells from the stomach of the bullfrog, Bufo marinus. Emphasis will be placed on patch-clamp techniques to record both whole-cell and single-channel currents. The specific goals for which support is requested are studies of the mechanism of potassium channel activation by arachidonic acid and related fatty acids which has been observed in preliminary experiments. Studies will will be carried out to determine whether potassium channel activaton is caused by arachidonic acid and other fatty acids themselves or by metabolites derived from these fatty acids. A variety of compounds structurally related to arachidonic acid and other fatty acids will be examined to establish which structural features are required for the molecules to be effective in inducing potassium current. Possible endogenous agents that may be releasing the fatty acids will be sought and identified, and any additional effects of fatty acids on channels will be studied. The role of arachidonic acid and other fatty acids as second messengers in transmission of external signals to the biochemical machinery within cells has recently become the focus of attention in a number of cell systems. The preliminary observations of Drs. Singer and Walsh that these agents appear to affect ion channels in the membranes of smooth muscle cells suggest a previously unexpected mechanism by which the excitability and contractile activity of these cells may be modulated. The further analysis of these new observations may lead to important insights into the mechanisms of regulation of contraction of smooth muscle, and more generally into the mechanisms by which the permeability of cell membranes is regulated.

这项研究计划的长期目标是了解平滑肌细胞膜上离子通道的功能，以及递质、离子、代谢物、第二信使和膜电位对它们的调节。由于离子通道控制膜电位，作为神经递质和第二信使机制的主要靶点之一，是动作电位的基础，并控制钙离子进入细胞内，因此它们在调节平滑肌收缩中起着核心作用。这些实验使用了从牛蛙(Bufo Marinus)胃部新鲜分离的细胞。重点放在记录全细胞和单通道电流的膜片钳技术上。需要支持的具体目标是研究花生四烯酸和相关脂肪酸激活钾通道的机制，这已在初步实验中观察到。将进行研究，以确定钾通道激活是由花生四烯酸和其他脂肪酸本身引起的，还是由这些脂肪酸产生的代谢物引起的。我们将研究与花生四烯酸和其他脂肪酸在结构上相关的各种化合物，以确定这些分子需要哪些结构特征才能有效地诱导钾电流。将寻找和识别可能释放脂肪酸的可能内源性因素，并研究脂肪酸对通道的任何额外影响。花生四烯酸和其他脂肪酸作为第二信使将外部信号传递到细胞内的生化机制中的作用最近已成为许多细胞系统关注的焦点。Singer博士和Walsh博士的初步观察表明，这些药物似乎影响了平滑肌细胞膜上的离子通道，这表明了一种先前意想不到的机制，通过这种机制，这些细胞的兴奋性和收缩活动可能被调节。对这些新观察结果的进一步分析可能会导致对平滑肌收缩调节机制的重要洞察，更广泛地说，可能导致对细胞膜通透性调节机制的深入了解。