Analysis of nicotinic acetylcholine receptor function in C. elegans

描述：烟碱胆碱能信号在哺乳动物神经系统中起关键作用。烟碱型乙酰胆碱受体作为突触后受体介导神经元之间的兴奋性信号传导，并且从突触外位点，在大脑和脊髓的几乎每个区域的不同突触类型处调节神经递质释放。烟碱胆碱能信号的改变与许多衰弱性神经系统疾病相关，包括阿尔茨海默病、精神分裂症和某些形式的癫痫。此外，尼古丁与神经系统中的烟碱受体结合，启动导致尼古丁成瘾的细胞和分子级联反应。尽管烟碱信号在正常脑生理学和神经元功能障碍中具有明显的重要性，但我们对烟碱信号实现的分子机制的理解存在重大差距，并且影响神经系统中胆碱能信号的调节途径仍然定义不清。这个建议采用了一个高度易处理的模式系统，线虫C。elegans，研究胆碱能信号在一个确定的神经系统的分子细节。我们的初步数据表明，烟碱受体在调节运动神经元的兴奋性中起着关键作用。elegans电机电路在目标1中，我们将检验特定受体类型的表达和定位仅限于运动神经元亚群的假设，确定对神经元上烟碱受体的适当定位重要的通路的分子性质，并检验特定受体类型在C.优雅的行为在目标2中，我们将使用膜片钳电生理学直接测量运动神经元的胆碱能电流，并评估这些受体在运动神经元生理学中的作用。在目标3中，我们将使用一种强大的遗传方法来揭示调节胆碱能信号传导到神经元的新分子通路的组成部分。我们希望我们的研究将提供基本的见解烟碱受体在中枢神经系统的功能机制。此外，在我们的实验中，调节突触形成和功能的遗传途径的鉴定和功能表征将最终产生用于治疗涉及胆碱能信号传导的神经系统疾病的治疗策略的新型药物靶点。

DESCRIPTION: Nicotinic cholinergic signaling plays key roles in the mammalian nervous system. Nicotinic acetylcholine receptors mediate excitatory signaling between neurons as post-synaptic receptors and, from extrasynaptic sites, modulate neurotransmitter release at diverse synapse types across virtually every area of the brain and spinal cord. Alterations in nicotinic cholinergic signaling are associated with a number of debilitating neurological disorders including Alzheimer's disease, schizophrenia and certain forms of epilepsy. Moreover, nicotine binding to nicotinic receptors in the nervous system initiates the cellular and molecular cascade that results in nicotine addiction. Despite the clear importance of nicotinic signaling in normal brain physiology and neuronal dysfunction, there are major gaps in our understanding of the molecular mechanisms by which nicotinic signaling is achieved, and the regulatory pathways that impact cholinergic signaling in the nervous system remain poorly defined. This proposal employs a highly tractable model system, the nematode C. elegans, to investigate the molecular details of cholinergic signaling in a defined nervous system. Our preliminary data show that nicotinic receptors play key roles in regulating the excitability of motor neurons in a well-characterized C. elegans motor circuit. In Aim 1, we will test the hypothesis that the expression and localization of specific receptor types are restricted to subsets of motor neurons, determine the molecular nature of pathways important for proper localization of nicotinic receptors on neurons, and test the roles of specific receptor types in the control of C. elegans behavior. In Aim 2, we will use patch clamp electrophysiology to directly measure cholinergic currents from motor neurons and assess the roles of these receptors in motor neuron physiology. In Aim 3, we will use a powerful genetic approach to uncover components of novel molecular pathways that regulate cholinergic signaling onto neurons. We expect that our studies will provide fundamental insights into the mechanisms of nicotinic receptor function in the central nervous system. Additionally, the identification and functional characterization of genetic pathways that regulate synapse formation and function in our experiments will ultimately yield novel drug targets for therapeutic strategies designed to treat neurological disorders involving cholinergic signaling.