TRANSIENT EXPRESSION OF CHOLINERGIC MARKERS IN THE PVCN

PVCN 中胆碱能标记物的瞬时表达

• 批准号: 7154105
• 负责人: Barbara J Morley
• 金额: $ 26.74万
• 依托单位: FATHER FLANAGAN'S BOYS' HOME
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-12-06 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7154105
• 关键词: ARHGEF5 gene; Acetylcholine; Acetylcholinesterase; Adult; Affect; Affinity; Age; Agonist; Auditory; Auditory system; Axon; Behavior; Biochemical; Brain; Bungarotoxins; Calcium; Carrier Proteins; Cells; Child; Choline; Choline O-Acetyltransferase; Cholinergic Agents; Cholinergic Receptors; Chromosome Pairing; Cochlear nucleus; Data; Development; Diffuse; Environment; Enzymes; Event; Extracellular Space; Gene Expression; Glutamate Receptor; Glutamates; Goals; Hearing; Histocytochemistry; Image; In Situ Hybridization; Laboratories; Language Disorders; Light; Link; Literature; Localized; Long-Term Effects; Measures; Methods; Microscopic; Minor; Molecular; Mothers; Mutant Strains Mice; N-Methyl-D-Aspartate Receptors; N-Methylaspartate; Nerve; Nerve Tissue; Neurons; Nicotine; Nicotinic Agonists; Nicotinic Antagonists; Nicotinic Receptors; Octopus; Pathway interactions; Presynaptic Terminals; Proteins; Purpose; Rattus; Receptor Gene; Regulation; Research Personnel; Rodent; Role; Series; Site; Slice; Smoke; Synapses; System; Testing; Toxin; Vertebral column; Vesicle; Vesicular Transport Proteins; Week; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; amino 3 hydroxy 5 methylisoxazole 4 propionate; base; cholinergic; cholinergic neuron; day; deafness; experience; fetal; mRNA Expression; methyllycaconitine; nanoGold; neurochemistry; neuronal cell body; neurotransmission; novel; postnatal; postsynaptic; presynaptic; programs; pup; receptor binding; receptor expression; synaptic function; synaptogenesis; uptake

DESCRIPTION (provided by applicant): The pathways and synaptic connections in the brain are established by a finely orchestrated series of neurochemical events. Although central auditory system synapses are modified by experience after the onset of hearing, synaptic connectivity is established before the eighth nerve is responsive to the external environment. There is an emerging literature indicating that some enzymes and proteins with minor roles in neurotransmission in the adult brain have major roles in guiding axons and establishing synapses during development. Acetylcholine (ACh), acetylcholinesterase (AChE) and the a7 nicotinic acetylcholine receptor (nAChR) are among the neurochemicals that regulate synaptic events, including the expression of genes obligatory for mature synapse formation in target neurons. In our laboratory, we have discovered a pathway projecting to the rodent octopus cell region of the posterior ventral cochlear nucleus (PVCN) that transiently expresses AChE and the a? nAChR during the second postnatal week. Ultrastructural studies indicate that few synaptic junctions are present by postnatal day 3, and are abundant by P5. The temporal sequence of the expression of the cholinergic markers, together with electrophysiological data from other laboratories, suggests that ACh and related enzymes and proteins are essential for the maturation of synapses. One of their functions may be to modulate glutamatergic receptor gene expression. Toxins that specifically affect cholinergic receptors, such as nicotine, concentrate in the fetal and postnatal brain in physiologically relevant concentrations. While this would not cause deafness, it could contribute to long-term language deficits. The goal of the proposed studies is to elucidate the cholinergic molecular mechanisms related to the maturation of synapses and regulation of NMDA receptor gene expression in the rodent PVCN. The overall hypothesis is that the diffuse release of ACh regulates NMDA glutamate receptor expression by regulating intracellular calcium through a7 nicotinic acetylcholine receptors clustered on postsynaptic sites of PVCN octopus cells. The specific hypotheses are: (1) ACh release is nonvesicular; (2) nAChRs are clustered postsynaptically on octopus cells; ACh (3) a7 nAChRs on octopus cells regulate intracellular calcium before, but not after, the onset of hearing; (4) nicotine administration will upregulate NMDA, but not AMPA, receptor gene expression; and (5) ACh, through a7 nAChRs, regulates NMDA glutamate receptor expression.

描述（由申请人提供）：大脑中的通路和突触连接是通过一系列精心策划的神经化学事件建立的。尽管中枢听觉系统突触在听力出现后会根据经验进行修改，但突触连接是在第八神经对外部环境做出反应之前建立的。新兴文献表明，一些在成人大脑神经传递中起次要作用的酶和蛋白质在发育过程中在引导轴突和建立突触方面发挥着重要作用。乙酰胆碱 (ACh)、乙酰胆碱酯酶 (AChE) 和 a7 烟碱乙酰胆碱受体 (nAChR) 是调节突触事件的神经化学物质，包括目标神经元中成熟突触形成所必需的基因表达。在我们的实验室中，我们发现了一条投射到啮齿动物章鱼后腹侧耳蜗核（PVCN）细胞区域的通路，该通路瞬时表达AChE和a？ nAChR 在产后第二周。超微结构研究表明，到出生后第 3 天，突触连接很少出现，而到 P5 时突触连接却很丰富。胆碱能标记物表达的时间序列以及其他实验室的电生理学数据表明，ACh 以及相关酶和蛋白质对于突触的成熟至关重要。它们的功能之一可能是调节谷氨酸能受体基因表达。专门影响胆碱能受体的毒素，例如尼古丁，以生理相关浓度集中在胎儿和出生后的大脑中。虽然这不会导致耳聋，但可能会导致长期的语言障碍。本研究的目的是阐明啮齿动物 PVCN 中与突触成熟和 NMDA 受体基因表达调节相关的胆碱能分子机制。总体假设是，ACh 的弥漫释放通过聚集在 PVCN 章鱼细胞突触后位点的 a7 烟碱乙酰胆碱受体调节细胞内钙，从而调节 NMDA 谷氨酸受体的表达。具体假设是：（1）ACh释放是非囊泡的； (2) nAChR 聚集在章鱼细胞的突触后；章鱼细胞上的 ACh (3) a7 nAChR 在听力出现之前而非之后调节细胞内钙； (4)尼古丁给药会上调NMDA受体基因表达，但不会上调AMPA受体基因表达； (5)ACh通过a7 nAChRs调节NMDA谷氨酸受体的表达。