EXPRESSION OF NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS

描述(摘自申请者摘要)：尼古丁受体(NAChRs) 参与运动肌肉，创造记忆，并增强我们最 基本行为。中枢神经系统nAChRs与正常认知功能有关， 它们的丧失可能是与中枢胆碱能相关的记忆缺陷的基础 神经退行性变。胆碱能投射的刺激或应用 尼古丁通过对突触后nAChRs的门控直接和间接地兴奋神经元 通过激活突触前nAChRs改变兴奋性，从而增强 发射机释放。尽管nAChRs在突触“调节”和 在传播过程中，人们对导致这种疾病的调控机制知之甚少 NAChRs在中枢神经系统的表达、生物物理特性或细胞靶向。 这个应用程序检查潜在的细胞和分子机制 NAChR在特定中枢神经系统突触的表达调控。我们首先测试一下 突触前和突触后伙伴之间的相互作用控制nAChRs的表达 中枢神经系统胆碱能感受部位的成熟。突触的作用 NAChRs在突触前部位表达和靶向的相互作用 将在生物物理和分子生物学的联合研究中进行检测 内脏运动神经元和内侧缰核神经元治疗前后的nAChRs 突触形成。输入诱发突触后变化的平行研究 NAChRs比较nAChRs在 突触发生前后的脚间神经元和杏仁核神经元。我们是下一个 验证富含半胱氨酸结构域的中性调节蛋白(CRD-NRG)是 中枢神经系统胆碱能神经元的突触分化所需。 先前的研究表明，输入来源的CRD-NRG控制着nAChRs的表达 鸡PNS及其CRD-NRG和NRG受体(ERBbs)的表达 鸡和小鼠的胆碱能神经元和胆碱能神经元。要确定 CRD-NRG在哺乳动物突触发生中的作用，我们产生了CRD-NRG的“敲除” 老鼠。建议的实验评估CRD-NRG、ERBbs和nAChRs的表达 内侧缰核、脚间沟内胆碱能神经元的发育 和杏仁核神经元。如果中枢神经系统的成熟需要CRD-NRG 胆碱感受性突触，因为它在外周，我们预测 正常表达谱和细胞靶向的扰动 NAChR通道通向CRD-NRG(-/-)小鼠的突触前和突触后部位。决赛， 长期目标是确定CRD-NRG激活的信号级联。 这些研究追求的初步发现是顺行和逆行 CRD-NRG/erbB相互作用激活了信号级联反应。

DESCRIPTION (Verbatim from Applicant's Abstract): Nicotinic receptors (nAChRs) participate in moving muscles, making memories, and reinforcing our most fundamental behaviors. CNS nAChRs are implicated in normal cognitive functions, and their loss may underlie memory deficits associated with central cholinergic neurodegeneration. Stimulation of cholinergic projections or application of nicotine directly excites neurons by gating postsynaptic nAChRs and indirectly alters excitability by activating presynaptic nAChRs, thereby enhancing transmitter release. Despite the key role of nAChRs in synaptic "tuning" and transmission, little is known of the regulatory mechanisms responsible for the expression, biophysical profile or cellular targeting of nAChRs in the CNS. This application examines the cellular and molecular mechanisms underlying the regulation of nAChR expression at specific CNS synapses. We first test whether interactions between pre- and postsynaptic partners control nAChRs expression and the maturation of cholinoceptive sites in the CNS. The role of synaptic interactions in the expression and targeting of nAChRs to presynaptic sites will be assayed in combined biophysical and molecular biological studies of nAChRs in visceral motor neurons and medial habenula neurons before and after synapse formation. Parallel studies of input-induced changes in postsynaptic nAChRs compare the expression profile and properties of nAChRs in interpeduncular and amygdala neurons before and after synaptogenesis. We next test the hypothesis that cysteine-rich-domain neuregulins (CRD-NRG) are required for the synaptic differentiation of cholinoceptive neurons in the CNS. Prior studies show that input-derived CRD-NRG controls nAChRs expression in chick PNS and that CRD-NRG and NRG receptors (erbBs) are expressed by cholinergic and cholinoceptive neurons in chick and mouse. To determine the role of CRD-NRG in mammalian synaptogenesis, we generated a CRD-NRG "knock-out" mouse. Proposed experiments assess the expression of CRD-NRG, erbBs and nAChRs in developing cholinoreceptive neurons within medial habenula, interpeduncular and amygdala neurons. If CRD-NRG is required for the maturation of CNS cholinoceptive synapses, as it is in the periphery, we predict significant perturbations of the normal profile of expression and cellular targeting of nAChR channels to pre- and postsynaptic sites in CRD-NRG (-/-) mice. A final, long-range goal is to determine the signaling cascades activated by CRD-NRG. These studies pursue initial findings that both anterograde and retrograde signaling cascades are activated by CRD-NRG/erbB interactions.