IONIC CHANNELS IN DISSOCIATED SMOOTH MUSCLE CELLS

这项建议的目的是研究流畅的离子通道 肌细胞膜及其对这些通道的调控 电位、神经递质、离子、代谢物和酶。这些离子 控制膜电位的通道，是 神经传递，低于动作电位，负责 Ca++进入细胞内。因此，它们在 控制平滑肌收缩，这是一个极具治疗意义的话题 重要性(例如，在高血压、血管痉挛和子宫和 胃肠收缩功能)。绕过相关的问题 随着对组织的研究，我们将采用一种制剂 新鲜分离的中华大蟾蜍单个平滑肌细胞 从电生理、生物化学的角度进行了详细的描述 从形态上看。研究将主要集中在 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，也记录 在内部条件下来自整个电池的宏观电流 胞液成分是可以改变的。将有五个主要领域 研究：1)钙通道，2)大电导钙激活的钾通道， 3)M-电流与乙酰胆碱的作用；4)某些 神经肽，以及5)共价修饰和胞浆调节剂 频道。从这些研究中，应该会有更好的理解 平滑肌和这些离子通道的电活动 常见于平滑肌肉和其他类型的细胞。

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.