Nicotinic Acetylcholine Receptors & Neuronal Development

烟碱乙酰胆碱受体

• 批准号: 6682169
• 负责人: PHYLLIS C PUGH
• 金额: $ 11.72万
• 依托单位: UNIVERSITY OF TOLEDO HEALTH SCI CAMPUS
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-25 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6682169
• 关键词: Xenopus oocyte; acetylcholine; cell death; chick embryo; ciliary ganglion; confocal scanning microscopy; congenital disorders; developmental neurobiology; electrophysiology; electroporation; immunocytochemistry; immunoprecipitation; neurons; neurotoxicology; nicotine; nicotinic receptors; northern blottings; polymerase chain reaction; receptor expression; receptor sensitivity; synaptogenesis; tissue /cell culture

DESCRIPTION (provided by applicant): Nicotine, as consumed through tobacco use, is a drug abused by nearly 47 million Americans. Understanding the consequences of nicotine exposure is therefore a major health issue in the United States and of interest at epidemiological, clinical and basic science levels. Of particular concern are the approximately 20% of women who smoke, two-thirds of whom continue to do so during pregnancy. Epidemiological studies link maternal smoking to low infant birthweight, reduced head size, congenital heart defects, isolated craniosynostosis, craniofacial anomalies, and limb malformations. As nicotine is a major toxic component of tobacco smoke and is present at equivalent levels in fetal and maternal tissues, it is strongly implicated as a causative agent of such defects. The physiological effects of nicotine are exerted by activation of nicotinic acetylcholine receptors (AChRs). AChRs are pentameric, ligand-gated ion channels, ubiquitously expressed in both the central and peripheral nervous systems, as well as in skeletal muscle. Thus, in addition to the established functions of AChRs in signaling, addiction, task attention, and neurological disease, AChRs are also likely to participate in smoking-related birth defects. The ability of nicotine to cause such defects is consistent with the appearance of AChRs in neuronal precursors and in the human CNS prior to cortical development. The early appearance of AChRs and their known ability to influence neuronal survival and process outgrowth directly implicate them in normal neuronal development in vivo. At present, however, developmental roles for AChRs are novel and remain poorly understood. This proposal will analyze the developmental significance of neuronal AChRs using the embryonic chick ciliary ganglion (CG) as a model system. CG neurons are ideally suited for such studies because they express well-defined AChR types having distinct properties and unique functions. Moreover, the CG is accessible to manipulation throughout development, both in vivo and in cell culture. A major AChR type is sensitive to blockade by (-bungarotoxin ((Bgt). The investigator has previously shown that these (Bgt-AChRs influence process outgrowth and promote neuronal survival in culture. Further, preliminary studies suggest that (Bgt-AChRs can influence synapse formation on CG neurons in culture. The experiments described here will extend these findings to the in vivo setting using retroviral delivery of mutated AChR genes into embryos during neuronal development. These alterations will be assessed for their impact on neuronal survival (Aim 1), synapse formation (Aim 2), and AChR distribution (Aim 3). The proposed studies are expected to provide new information concerning the developmental significance of AChRs in vivo. Fulfilling the goals of this project will aid in developing the investigator's scientific independence and is expected to reveal additional clues for understanding how nicotine abuse contributes to birth defects.

描述（由申请人提供）： 尼古丁（Nicotine）被烟草使用所消耗，是近4700万美国人滥用的药物。因此，了解尼古丁暴露的后果是美国的主要健康问题，并且在流行病学，临床和基础科学层面上感兴趣。特别关注的是，大约20％的吸烟妇女，其中三分之二在怀孕期间继续这样做。流行病学研究将孕产妇吸烟与低婴儿体重，头部大小降低，先天性心脏缺陷，孤立的颅骨癌，颅面病，颅面异常和肢体畸形。由于尼古丁是烟草烟雾的主要有毒成分，并且存在于胎儿和母体组织中的同等水平，因此它是这种缺陷的致病药物。尼古丁的生理作用是通过烟碱乙酰胆碱受体（ACHR）激活来施加的。 ACHR是五聚体门控的离子通道，在中央和周围神经系统以及骨骼肌中均普遍表达。因此，除了ACHR在信号，成瘾，任务注意和神经疾病中的既定功能外，ACHR还可能参与与吸烟有关的先天缺陷。尼古丁引起这种缺陷的能力与神经元前体中ACHR的出现以及在皮质发育之前的人类中枢神经系统中的出现一致。 ACHR的早期出现及其影响神经元存活和过程生长的已知能力直接牵涉到体内正常神经元发育中。然而，目前，ACHR的发育作用是新颖的，并且仍然知之甚少。 该建议将使用胚胎鸡睫状神经节（CG）作为模型系统分析神经元ACHR的发育意义。 CG神经元非常适合此类研究，因为它们表达具有不同特性和独特功能的明确定义的ACHR类型。此外，在整个开发过程中，无论是在体内还是在细胞培养中，CG都可以通过操纵。 （-bungarotoxin（（（BGT））。研究者先前表明（BGT-ACHR会影响过程的生长并促进神经元生存）对阻断的封锁对阻滞敏感。此外，初步研究表明，BGT-ACHR可以在此培养中延伸这些发现，该研究的范围会影响这些范围。在神经元发育过程中，将ACHR基因变成胚胎。虐待导致先天缺陷。