SYNAPTIC MECHANISMS OF GENERAL ANESTHETIC ACTION

描述：本提案的广泛、长期目标是 在分子水平上理解一般药物的作用机制 麻醉剂对中枢神经系统突触传递的影响。 确定参与治疗和毒性的机制 现有麻醉剂的作用将促进 更具体的药物，副作用更少。 假设是 评估的是全身麻醉剂影响药剂释放递质- 和特定递质的突触前机制。 具体目标是 1)确定全身麻醉药对突触体的影响 神经递质释放; 2）确定全身麻醉的机制 对神经递质释放的影响;和3）调查的影响 全身麻醉剂对神经元Na+通道（介导麻醉剂 抑制谷氨酸释放）。 实验设计是为了识别 全身麻醉药对神经递质释放的影响 无细胞相互作用的亚细胞制备物（突触体） 并进行药理学分析，然后表征 通过分析麻醉作用的相关变化， 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。 的 使用的方法包括麻醉效果的神经化学分析， 自发和诱发谷氨酸，γ-氨基丁酸，去甲肾上腺素， 大鼠脑突触体释放多巴胺和胆囊收缩素-8; 突触体Na+、Ca 2+和C1-浓度的荧光分光光度测定， 膜电位和pH值;特异性药物作用的药理学分析 离子通道和蛋白激酶在麻醉药对 突触前Na+电流的膜片钳记录 在突触体融合形成的囊泡中。 突触前的确定 全身麻醉药对递质释放的影响， 这些作用，是必不可少的联系分子和细胞的行动， 麻醉剂对神经元功能的影响，从而了解 这种临床上重要但知之甚少的药物的作用。

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.