SYNAPTIC MECHANISMS OF GENERAL ANESTHETIC ACTION

描述：这项提议的广泛、长期目标是 从分子水平上理解大黄连的作用机制 麻醉剂对中枢神经系统突触传递的影响。 治疗和毒性作用机制的鉴定 现有麻醉剂的作用将促进 更具体的药物和更少的不良反应。假设是 评估的是，全身麻醉剂影响药物释放递质- 以及特定于递质的突触前机制。具体目标是 1)测定全身麻醉药对突触体的影响 神经递质释放；2)确定全麻药的作用机制 对神经递质释放的影响；以及3)研究 全身麻醉药对神经元Na+通道(介导麻醉剂)的作用 抑制谷氨酸释放)。实验设计是为了识别 全麻药对慢性阻塞性肺疾病患者神经递质释放的影响 无细胞相互作用的亚细胞制备(突触体) 并服从于药理分析，然后表征 从相关变化分析麻醉作用的机制(S) 突触前离子通道功能、细胞内离子浓度、膜 潜在的，突触前受体功能和第二信使系统。这个 使用的方法包括对麻醉效果的神经化学分析 自发和诱发的谷氨酸，γ-氨基丁酸，去甲肾上腺素， 大鼠脑突触体内释放多巴胺和缩胆囊素-8； 突触体钠、钙、氯离子浓度的荧光分光光度测定法 膜电位和pH；特定作用的药理学分析 离子通道和蛋白激酶在麻醉药对血管内皮细胞的影响 递质释放；膜片钳记录突触前钠电流 在融合突触体形成的囊泡中。突触前突触的测定 全麻药对递质释放的影响及其机制 这些效应在连接分子和细胞活动中是必不可少的 麻醉药对神经功能的影响，从而有助于了解 这类药物的作用在临床上很重要，但却知之甚少。

DESCRIPTION: The broad, long-term objective of this proposal is to understand at a molecular level the mechanisms of action of general anesthetics on synaptic transmission in the central nervous system. Identification of the mechanisms involved in the therapeutic and toxic effects of existing anesthetic agents will facilitate the development of more specific agents with fewer adverse effects. The hypothesis to be evaluated is that general anesthetics affect transmitter release by agent- and transmitter-specific presynaptic mechanisms. The Specific Aims are to 1) Determine the effects of general anesthetics on synaptosomal neurotransmitter release; 2) Determine the mechanisms of general anesthetic effects on neurotransmitter release; and 3) Investigate the effects of general anesthetics on neuronal Na+ channels (which mediate anesthetic inhibition of glutamate release). The experimental design is to identify the effects of general anesthetics on neurotransmitter release in a subcellular preparation (synaptosomes) that is free of cellular interactions and amenable to pharmacological analysis, and then to characterize the mechanism(s) of the anesthetic effects by analyzing associated changes in presynaptic ion channel function, intracellular ion concentrations, membrane potential, presynaptic receptor function and second messenger systems. The methods to be used include neurochemical analysis of anesthetic effects on spontaneous and evoked glutamate, gamma-aminobutyric acid, norepinephrine, dopamine and cholecystokinin-8 release from rat brain synaptosomes; spectrofluorimetric assays of synaptosomal Na+, Ca2+, and C1-concentrations, membrane potential and pH; pharmacologic analysis of the roles of specific ion channels and protein kinases in the effects of anesthetics on transmitter release; and patch-clamp recording of presynaptic Na+ currents in vesicles made by fusing synaptosomes. Determination of the presynaptic effects of general anesthetics on transmitter release, and the mechanisms of these effects, is essential in linking the molecular and cellular actions of anesthetics on neuronal function and thus in understanding the mechanisms of action of this clinically important, but poorly understood, class of drugs.