IONIC CHANNELS IN DISSOCIATED SMOOTH MUSCLE CELLS

这个提议的目的是研究光滑的细胞中的离子通道。 肌细胞膜和这些通道的控制膜 电位、神经递质、离子、代谢物和酶。 这些离子 通道控制膜电位，是靶点， 神经传递，是动作电位的基础， Ca++进入细胞。 因此，他们在这方面发挥着核心作用。 平滑肌收缩的控制，一个相当有治疗意义的话题， 重要性（例如，在高血压、血管痉挛和子宫和 胃肠收缩性）。 为了避免相关的问题 在对组织的研究中，我们将采用一种制备方法， 新鲜分离的单个平滑肌细胞，来自海洋蟾蜍， 已经有了一些详细的特征--电生理学的，生化的 和形态学上。 这些研究将主要是 电生理学，重点是膜片钳技术， 记录通过单个离子通道的电流， 在内部条件下，来自整个细胞的宏观电流 胞质组成可以改变。 将有五个主要领域， 研究：1）Ca++通道，2）大电导Ca++激活的K+通道， 3)M-电流和乙酰胆碱的作用; 4）某些 神经肽，和5）共价修饰和胞质调节剂 渠道 从这些研究中，我们应该能更好地理解 平滑肌和离子通道的电活动 常见于平滑肌和其他细胞类型。

The purpose of this proposal is to investigate ionic channels in the smooth muscle cell membrane and the control of these channels by membrane potential, neurotransmitters, ions, metabolites and enzymes. These ionic channels control the membrane potential, are the targets of neurotransmission, underly the action potential and are responsible for Ca++ entry into the cell. Consequently, they play a central role in the control of smooth muscle contraction, a topic of considerable therapeutic importance (e.g., in hypertension, vasospasm, and uterine and gastrointestinal contractility). To circumvent the problems associated with studies on tissue, we shall employ a preparation of freshly-dissociated single smooth-muscle cells from Bufo marinus which have been characterized in some detail--electrophysiologically, biochemically and morphologically. The studies will be predominantly electrophysiological with an emphasis on the patch-clamp technology to record currents through single ionic channels and also to record macroscopic currents from the whole cell under conditions where internal cytosolic composition can be altered. There will be five major areas of study: 1) Ca++ channels, 2) Large-conductance Ca++-activated K+ channels, 3) M-current and the action of acetylcholine, 4) The action of certain neuropeptides, and 5) Covalent modification and cytosolic regulators of channels. From these studies, there should emerge a better understanding of the electrical activity of smooth muscle and of those ionic channels common to smooth muscle and other cell types.