General Anesthetic Sites on Ligand-Gated Ion Channels

描述（由申请人提供）：在美国，每年约有2500万患者使用治疗指数非常低的药物进行全身麻醉。全身麻醉的分子机制仍然未知，阻碍了改进药物的设计。全身麻醉剂作用于配体门控通道的超家族，包括GABA和甘氨酸门控的抑制性阴离子通道和5 -羟色胺和乙酰胆碱门控的兴奋性阳离子通道。本PPG关注的是

DESCRIPTION (provided by applicant): Some 25 million patients are given general anesthesia each year in the USA using agents with very low therapeutic indices. The molecular mechanisms of general anesthesia remain unknown, hampering the design of improved agents. General anesthetics act on a superfamily of ligand gated channels which include inhibitory anion channels gated by GABA and glycine, and excitatory cation channels gated by serotonin and acetylcholine. This PPG focuses on the ability of general anesthetics to enhance the activity of the inhibitory GABAA receptor (GABAAR) and to inhibit (and in some cases enhance) the excitatory neuronal serotonin (5-HT3R) and nicotinic acetylcholine receptors (nAcChoR). The overall hypothesis is that the various action of general anesthetics are mediated by a number of binding sites on these receptors, that their location and affinity varies with the anesthetic's structure and the receptor's conformation, and that parallels exist between the two homologous receptors. The overall aims of the PPG are to: (i) locate anesthetic binding sites on the GABAA, 5-HT3 and nAcCho receptors, and (ii) define the functional significance of each site. Two complementary techniques will be employed to detect sites, photoaffinity labeling (Projects 2, 3 and 5) and site directed mutagenesis (Projects 1, 3, 4 and 5). Project 1 will characterize the pharmacology of the 5-HT3 receptor and interact with Projects 2 and 3 who will locate the sites of action on activated (time-resolved photolabeling) and desensitized receptor states of alcohols, etomidate and propofol photolabels. Project 4 will define in detail the kinetic mechanisms of anesthetic action on GABAARs using rapid perfusion patch clamp techniques in wild type and mutated receptors, incorporating the photolabeling results to guide mutagenesis and interpretation. Project 5 will locate general anesthetic sites on GABAA receptors using photoactivable general anesthetics. Synthetic and Protein Chemistry Cores are essential for developing novel photoaffinity general anesthetics and for locating the sites of photoincorporation, respectively. A Protein Production Core will supply neuronal receptors to each of the projects.