NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS

长远目标是O！这项研究是为了了解 神经元烟碱乙酰胆碱受体（AChR）受到调节。 我们的方法一直是研究乙酰胆碱受体在一个非常简单和易于处理的 系统，青蛙心神经节。 大脑中的副交感神经元 这个神经节位于薄薄的房间隔中，在那里 它们可以用各种不同的 显微技术。 神经节乙酰胆碱受体可以研究与 ACh离子导入法和两种AChR特异性配体：1） 针对鱼雷AChR的交叉反应单克隆抗体， 2)神经-银环蛇毒素（也称为3.1银环蛇毒素，毒素F， 和k-银环蛇毒素），其阻断了 神经节这些AChR特异性配体的结合可以是 用荧光显微镜、放射自显影术及两者观察 免疫过氧化物酶和免疫金电镜。 主要 需要解决的问题是： 1. 乙酰胆碱受体在皮肤表面的分布 神经节细胞 乙酰胆碱受体是否在突触后 像骨骼肌中的神经元膜一样？ 2. AChRs的分布如何变化，当神经元 失去了神经原始分布是否在 神经再生术神经支配是否影响AChR分布 神经节细胞以类似于骨骼肌中发现的方式 肌肉？ 3. AChR特异性配体的结果与 通过离子电渗法测定乙酰胆碱受体功能获得的那些？ AChR的功能测定可能受到以下因素的影响： 乙酰胆碱酯酶在细胞表面，这种酶可能 它本身受神经支配。 这些问题代表了理解 AChR分布受调节的机制。 我们还计划 通过寻找 其他蛋白质，可能是重要的乙酰胆碱受体集群上的 神经元表面，并通过寻找cDNA探针， 可以研究表达。 这些研究应该增加我们对尼古丁是如何 神经元上的乙酰胆碱受体受到调节。 这反过来可能导致 更好地了解中枢性疾病， 功能被破坏。

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.