Endocannabinoids and tonic GABA in the dentate gyrus.

齿状回中的内源性大麻素和补品 GABA。

• 批准号: 7473458
• 负责人: CHARLES J FRAZIER
• 金额: $ 4.03万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-15 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7473458
• 关键词: Acids; Address; Affinity; Agonist; Area; Basic Science; Bathing; Behavioral; Calcium; Cannabinoids; Cells; Cholinergic Agents; Cholinergic Receptors; Chromosome Pairing; Chronic; Class; Computer information processing; Data; Dependence; Drug abuse; Endocannabinoids; Etiology; Exposure to; Functional disorder; Glutamates; Goals; Hilar; Hippocampus (Brain); In Vitro; Lead; Learning; Marijuana Abuse; Mediating; Memory; Modeling; Muscarinic Acetylcholine Receptor; Muscarinic Agonists; Neurons; Optics; Play; Preparation; Presynaptic Terminals; Rattus; Regulation; Research Personnel; Role; Signal Transduction; Source; Specificity; Synapses; System; Techniques; Temporal Lobe Epilepsy; Testing; Time; Work; base; cannabinoid receptor; cholinergic; dentate gyrus; design; gamma-Aminobutyric Acid; insight; memory process; nerve supply; neurophysiology; postsynaptic; presynaptic; programs; receptor; research study

This is a basic science proposal designed to use in vitro electrophysiological and optical techniques to further our understanding of the neurophysiological mechanisms responsible for modulating the activity of synaptic inputs to hilar mossy cells. These unusual excitatory local circuit neurons receive strong glutamatergic, GABAergic, and likely cholinergic innervation from a variety of intrinsic and extrinsic sources. Normal function of mossy cells has been postulated to play a prominent role in information processing and memory formation in the hippocampus, while their loss and/or dysfunction has been implicated in the etiology of temporal lobe epilepsy. Preliminary data indicate that the activity of both inhibitory and excitatory inputs to mossy cells is modulated by depolarization-induced release of endogenous cannabinoids. Aim 1 of this proposal will provide a complete characterization of cannabinoid dependent signaling initiated by activation of mossy cells, and examine the role of postsynaptic cholinergic receptors in modulating the threshold for endocannabinoid release. Preliminary data has also indicated that presynaptic GABAergic receptors are expressed on some excitatory afferents to hilar mossy cells and further suggested that these receptors are likely subject to tonic inhibition by ambient GABA. Thus, Aim 2 will focus on ambient GABA as a potential modulator of these excitatory afferents and will ultimately determine if there is a useful relationship between endocannabinoid mediated retrograde signaling and inhibitory tone. Finally, Aim 3 will test the hypothesis that endocannabinoid mediated retrograde signalling in this system is impaired by chronic exposure to natural and/or synthetic cannabinoid agonists. These experiments may expose specific neurophysiological mechanisms that are fundamentally involved in regulation of excitability, information processing, and memory formation in the dentate gyrus, and further determine how they are altered over time in a chronic model of drug abuse.

这是一项基础科学提案，旨在使用体外电生理和光学技术， 进一步我们的神经生理机制的理解负责调节的活动， 到门苔藓细胞的突触输入。这些不寻常的兴奋性局部回路神经元接受强烈的 来自各种内源性和外源性的多巴胺能、GABA能和可能的胆碱能神经支配 源苔藓细胞的正常功能被认为在信息传递中起着重要作用 海马体中的加工和记忆形成，而它们的丧失和/或功能障碍已经被 与颞叶癫痫的病因有关初步数据显示， 对苔藓细胞的抑制性和兴奋性输入由去极化诱导的 内源性大麻素本提案的目标1将提供大麻素的完整表征 依赖的信号启动的苔藓细胞的激活，并检查突触后胆碱能的作用， 受体在调节内源性大麻素释放的阈值。初步数据还显示， 突触前GABA能受体表达于门苔藓细胞的某些兴奋性传入纤维上， 进一步表明这些受体可能受到周围GABA的紧张性抑制。因此，目标2 将重点放在周围的GABA作为这些兴奋性传入的潜在调制器，并最终将 确定内源性大麻素介导的逆行信号传导与 抑制音最后，目标3将测试内源性大麻素介导的逆行信号传导的假设， 在该系统中，通过长期暴露于天然和/或合成大麻素激动剂而受损。这些 实验可能揭示特定的神经生理机制，从根本上参与 调节齿状回的兴奋性、信息处理和记忆形成，以及进一步 确定它们在慢性药物滥用模型中是如何随着时间的推移而改变的。