EXPRESSION OF NEURONAL NICOTINIC ACETYLOCHOLINE RECEPTOR

许多中枢和外周胆碱能突触的突触传递 由烟碱乙酰胆碱受体通道（nAChRs）介导。 神经元突触处的烟碱型AChR（与神经肌肉突触处的那些不同） 连接）显然仅由两种类型亚基组成：配体 结合（alpha）和结构（beta）。 最近的分子和生物物理 研究表明α和β亚基序列的多样性 在神经系统和功能性神经系统中表达的基因， nAChR通道的特性。 因此，到目前为止，四个不同的阿尔法和三个 在神经组织中已经鉴定出不同的β亚单位转录物。 我们对特定中枢和外周神经系统的初步功能研究 神经元表明，多达四种不同的nAChR通道类型， 由单个神经元表达，nAChRs的功能类别 在胚胎发育过程中受到调控。 的关系 nAChR亚基基因序列多样性与功能之间的关系 神经元nAChR的性质尚不清楚。 本提案的主要目标是确定 nAChR亚单位序列涉及不同的功能类别， 表达的nAChRs以及这种受体多样性如何受 突触发生 我们建议在特定的中枢和中枢神经系统中研究nAChRs， 外周胆碱能神经元（内侧缰核和腰 交感神经链），很容易从早期 在体内的发育阶段，并可以删除和神经支配的 合适的突触输入，用于体外详细研究。 我们将联合收割机 生物物理和分子技术，以：1）确定细胞模式 nAChR亚基基因表达的影响，并研究是否 在表达的nAChR通道类别中存在相关变化2） 检查神经支配和去神经支配对nAChRs类型的影响 亚基基因和nAChR通道的表达和3）检查的作用， 单个亚基在特定功能类别的表达中， nAChRs。 最近的原位杂交研究表明，中枢烟碱 路径比以前认识到的要广泛得多。 目前还缺乏相关的功能研究。 拟议的研究 将构成第一个这样的受体亚单位的联合分析， 表达和通道功能在相同的神经元。 以来 选择用于研究的神经元群体所服从的生理作用 是如此的不同，这些研究很可能揭示出重要的差异， nAChRs在中枢和外周神经系统中的调节机制 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.