EXPRESSION OF NEURONAL NICOTINIC ACETYLOCHOLINE RECEPTOR

许多中枢和外周胆碱能突触的突触传递 是由烟碱型乙酰胆碱受体通道(NAChRs)介导的。 神经性突触上的尼古丁AChRs(不同于神经肌肉上的AChRs 连接)显然只由两种亚基组成：配体 结合(α)和结构(β)。最新的分子和生物物理 研究表明，α亚基和β亚基序列均存在多样性 在神经系统中表达的基因以及在功能 NAChR通道的属性。因此，到目前为止，有四个不同的阿尔法和三个 在神经组织中已经发现了不同的β亚基转录本。 我们对特定中枢和外周神经功能的初步研究 神经元表明多达四种不同的nAChR通道类型是 由单个神经元表达，nAChRs的功能类别 基因的表达在胚胎发育过程中受到调控。两国关系 NAChR亚单位基因序列多样性与功能 神经元nAChRs的特性尚不清楚。 这项提案的主要目标是确定生物多样性如何 NAChR亚单位序列与不同的功能类有关 NAChRs的表达以及这种受体多样性是如何通过 突触发生。我们建议在特定的中枢和中枢神经系统研究nAChRs 外周胆碱能神经元(内侧缰核和腰部神经元) 交感神经链)，从早期就很容易识别 在体内的发育阶段，可以被移除和神经 适当的突触输入用于体外详细研究。我们将联合起来 生物物理和分子技术：1)确定细胞模式 在发育过程中nAChR亚单位基因的表达，并检查 表达的nAChR通道的类别有相关变化2) 检测神经支配和去神经支配对nAChRs类型的影响 亚基基因和nAChR通道的表达以及3)检测 特定功能类的表达中的各个亚基 NAChRs。 最近的原位杂交研究表明，中枢性烟碱 这条道路比之前想象的要广泛得多。 免费的功能研究在很大程度上是缺乏的。建议进行的研究 将构成第一个这样的受体亚单位的联合分析 在相同的神经元中表达和通道功能。自.以来 被选为研究对象的神经元群体的生理作用 是如此的多样化，这些研究可能会揭示出重要的差异 NAChRs在中枢神经和外周神经中的调节机制 系统。

Synaptic transmission at many central and peripheral cholinergic synapses is mediated by nicotinic acetylcholine receptor channels (nAChRs). Nicotinic AChRs at neuronal synapses (unlike those at the neuromuscular junction) are apparently comprised of only two types of subunits: ligand binding (alpha) and structural (beta). Recent molecular and biophysical studies indicate diversity in both the sequences of alpha and beta subunit genes expressed in the nervous system as well as in the functional properties of nAChR channels. Thus, to date four different alpha and three different beta subunit transcripts have been identified in neural tissue. Our preliminary functional studies on particular central and peripheral neurons indicate that as many as four distinct nAChR channel types are expressed by individual neurons and that the functional classes of nAChRs expressed are regulated during the embryonic development. The relationship between the sequence diversity of nAChR subunit genes and functional properties of neuronal nAChRs is unclear. The primary goals of this proposal are to determine how the diversity in nAChR subunit sequences relates to the different functional classes of nAChRs expressed and how this receptor diversity is regulated by synaptogenesis. We propose to study nAChRs in specific central and peripheral cholinoceptive neurons (those of the medial habenula and lumbar sympathetic chain, respectively) that are readily identified from early developmental stages in vivo and that can be removed and innervated by the appropriate synaptic input for detailed study in vitro. We will combine biophysical and molecular techniques to: 1) determine the cellular pattern of nAChR subunit gene expression during development and to examine whether there are correlative changes in the classes of nAChR channels expressed 2) examine the influence of innervation and denervation on the types of nAChRs subunit genes and nAChR channels expressed and 3) examine the role of individual subunits in the expression of specific functional classes of nAChRs. The recent in situ hybridization studies reveal that central nicotinic pathways are considerably more extensive than previously appreciated. Complimentary functional studies are largely lacking. The proposed studies will constitute the first such combined analysis of receptor subunit expression and channel function in the same neurons. Since the physiological roles subserved by the neuronal populations chosen for study are so diverse, these studies are likely to reveal important differences n the mechanisms of regulation of nAChRs in the central vs peripheral nervous system.