VARIANCE AND SINGLE CHANNEL ANALYSIS OF ACH RECEPTORS

突触后存在乙酰胆碱受体(AChR)通道 神经和肌肉细胞的膜。这些通道将化学物质 乙酰胆碱(ACh)从突触前细胞释放到 突触后细胞的电去极化。ACHR频道有 用多种电生理、生化和 形态技术及其作用的分子机制是 开始被理解了。在这篇文章中，膜片钳方法 单通道检测将被用来研究 AChR频道。 ACh对受体有两种作用：ACh开放通道和延长 暴露于ACh会使受体脱敏。初步实验已经 表明在膜片钳中可以区分这些动作 通过将ACh快速、可逆地应用于切除的 从培养的肌肉细胞中提取的膜片。三类实验 将在拟议的调查中执行。1)激活 通过重复应用ACH而产生的大量通道。非平稳 将使用波动分析来计算明渠概率。 2)ACh长时间作用激活通道产生电流 放松一下。脱敏的动力学将从这些推论出来 放松一下。3)单个AChR通道在以下条件下的激活 无脱敏作用。激活速率常数将从以下位置获得 从单通道构造的开放时间直方图和关闭时间直方图 唱片。所有这些信息都将被用来构建动力学模型 通道的激活和脱敏。 酒精等麻醉剂对心脏功能的影响 Achr也将被研究。这些实验的结果将是 与麻醉剂相互作用模型预测的比较 与受体蛋白有关的分子。这种相互作用的含义 对于全身麻醉的机制，将被考虑。

Acetylcholine receptor (AChR) channels are found in the post-synaptic membranes of nerve and muscle cells. These channels translate the chemical signal of acetylcholine (ACh) release from the pre-synaptic cell into an electrical depolarization of the post-synaptic cell. AChR channels have been studied using a variety of electrophysiological biochemical and morphological techniques and the molecular mechanisms of its action are beginning to be understood. In this porposal, the patch clamp method of detecting single channels will be used to study the gating mechanisms of the AChR channel. ACh has two actions on the receptor: ACh opens the channel and prolonged exposures to ACh desensitize the receptor. Preliminary experiments have shown that it is possible to distinguish these actions in a patch clamp experiment by making rapid, reversible applications of ACh to an excised patch of membrane from cultured muscle cells. Three types of experiments will be performed in the proposed investigation. 1) The activation of large numbers of channels by repeated applications of ACh. Nonstationary fluctuation analysis will be used to calculate open channel probabilities. 2) The activation of channels by long applications of ACh produce current relaxations. The kinetics of desensitization will be deduced from these relaxations. 3) The activation of single AChR chanels under conditions of no desensitization. Activation rate constants will be obtained from open-and closed-time histograms constructed from the single channel records. All of this information will be used to construct a kinetic model of channel activation and desensitization. The effects of anesthetic agents such as alcohols on the function of the AChR will also be studied. The results of these experiments will be compared with the predictions of models for the interaction of anesthetic molecules with the receptor protein. The implications of such interactions for the mechanisms of general anesthesia will be considered.