NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS

长远的目标是！这项研究是为了了解如何 神经元烟碱型乙酰胆碱受体(AChRs)是受调控的。 我们的方法是以一种非常简单和容易处理的方式来研究AChRs 系统，蛙的心脏神经节。脑内的副交感神经元 该神经节位于细小的房间隔内， 可以使用各种不同的 显微技术。神经节细胞乙酰胆碱受体可以用 ACh离子导入和两种AChR特异性配体：1) 抗鱼雷AChRs和AChRs交叉反应单抗的研制 2)神经银环蛇毒素(又称3.1银环蛇毒素、F毒素、 和k-银环蛇毒素)，阻断脑组织中的受体功能。 神经节。这些AChR特异性配体的结合可以是 用荧光显微镜、放射自显影和这两者进行可视化 免疫过氧化物酶和免疫金电子显微镜。少校 需要解决的问题包括： 1.AChRs在地球表面的分布情况是怎样的 神经节细胞？AChRs在突触后丰富吗？ 像骨骼肌一样的神经细胞膜？ 2.AChRs的分布是如何变化的 丧失了神经？是否将原始分发恢复到 神经再支配？神经支配是否影响AChR在脑内的分布 神经节细胞的方式类似于在骨骼中发现的 肌肉？ 3.与AChR特异性配体相比，AChR特异性配体的结果如何 那些通过离子导入从功能上分析AChRs获得的？ AChR的功能测定可能会受到存在的影响 细胞表面的乙酰胆碱酯酶，这种酶可以 它本身受到神经支配的调节。 这些问题代表了理解 调节乙酰胆碱受体分布的机制(S)。我们还计划 通过搜索更多的机械性研究的初步尝试 在AChR上聚集的其他可能重要的蛋白质 神经元表面并通过寻找与哪个受体有关的cDNAs探针 表达是可以研究的。 这些研究应该会增加我们对尼古丁如何 神经元上的AChRs是受调控的。这反过来可能会导致 更好地了解胆碱能中枢紊乱 功能中断。

The long-range objective o! this research is to understand how neuronal nicotinic acetylcholine receptors (AChRs) are regulated. Our approach has been to study AChRs in a very simple and tractable system, the frog cardiac ganglion. The parasympathetic neurons in this ganglion are located in the thin interatrial septum, where they can be viewed with exceptional clarity using a variety of microscopic techniques. Ganglionic AChRs can be studied both with ACh iontophoresis and with two kinds of AChR-specific ligands: 1) cross-reacting monoclonal antibodies made against Torpedo AChRs and 2) neural-bungarotoxin (also known as 3.1 bungarotoxin, toxin F, and k-bungarotoxin), which blocks receptor function in the ganglion. The binding of these AChR-specific ligands can be visualized with fluorescence microscopy, autoradiography, and both immunoperoxidase and immunogold electron microscopy. The major questions to be addressed are: 1. What precisely is the distribution of AChRs on the surface of the ganglion cell? Are AChRs as enriched in the postsynaptic membrane of neurons as they are in skeletal muscle? 2. How does the distribution of AChRs change when neurons are denervated? Is the original distribution restored upon reinnervation? Does innervation influence AChR distribution on ganglion cells in a manner similar to that found in skeletal muscle? 3. How do results obtained with AChR-specific ligands compare with those obtained by assaying AChRs functionally via iontophoresis? The functional assay for AChR may be influenced by the presence of acetylcholinesterase on the cell surface, and this enzyme may itself be regulated by innervation. These questions represent a first step toward understanding the mechanism(s) by which AChR distribution is regulated. We also plan an initial foray into more mechanistic studies by searching for other proteins which may be important in AChR clustering on the neuronal surface and by looking for cDNA probes with which receptor expression may be studied. These studies should increase our understanding of how nicotinic AChRs on neurons are regulated. This may, in turn, lead to a better understanding of central disorders in which cholinergic function is disrupted.