CELLULAR RESPONSES TO HALLUCINOGENS

滥用致幻药物是5-羟色胺5- HT2A受体的部分激动剂。介导其致幻潜能的分子机制尚不清楚。利用我们之前在IRPG的跨学科工作中对致幻剂与H-HT/2A受体相互作用的理解，我们建议研究致幻剂和非致幻剂对5-HT2A受体的作用所引起的特定构象效应。与受体结合的激动剂使蛋白质稳定在特定的相对构象分布中。每种构象状态都倾向于与特定的g蛋白相互作用，诱导第二信使反应和内源基因的激活，并与调节蛋白相互作用，导致磷酸化、内化和脱敏。这些下游效应将被分析为在特定激动剂稳定的构象阶段的反射。将研究致幻潜力不同的完全和部分5-HT/2A激动剂，并调查观察到的反应差异的基础。H-HT2A受体的突变改变了相对激动剂的定位和效力、相对g蛋白的激活和失活期的稳定性，它们对不同致幻剂和非致幻剂在细胞系中引起的反应的影响将被确定。为了分析细胞系和体内神经元的细胞反应，我们将分析细胞信号传导（IRC）的内在报告者，它们在信号转导激活的反应中表现出快速的变化。IRC对致幻剂和非致幻剂的反应将在表达人类野生型和突变型受体代替内源性受体的敲入小鼠的皮质神经元中进行测量。这些研究将为细胞对5-HT/2A受体引起的致幻化学物质反应的分子基础提供见解，并可能促进新的治疗方式的发展。

Hallucinogenic drugs of abuse are partial agonists at the serotonin 5- HT2A receptor. The molecular mechanisms mediating their hallucinogenic potential are not known. Utilizing the understanding about hallucinogen interactions with the H-HT/2A receptor that we have developed from our previous inter-disciplinary work in an IRPG, we propose to study the specific conformational effects induced by hallucinogenic and non-hallucinogenic serotonergic agonists acting at the 5-HT2A receptor. Agonist binding to a receptor stabilizes the protein in a particular relative distribution of conformations. Each conformational state has a propensity to interact with specific G-proteins, inducing second messenger responses and activation of endogenous genes, and with regulatory proteins, leading to phosphorylation, internalization, and desensitization. These downstream effects will be assayed as reflections on the conformational stages stabilized by a particular agonist. Full and partial 5-HT/2A agonists that differ in their hallucinogenic potential will be studied and the basis for differences in the responses observed will be investigated. Mutations of the H-HT2A receptor that modify relative agonist positioning and efficacy, relative G-protein activation, and stability of the inactive stage have been identified and their effects on the responses elicited in cell lines by different hallucinogens and non- hallucinogens will be determined. In order to assay cellular responses both in cell lines and in neurons in vivo, we will assay intrinsic reporters of cellular signaling (IRC) that manifest rapid alterations in response to signal transduction activation. IRC responses to hallucinogens and non- hallucinogens will be measured in cortical neurons in knock-in mice expressing the human wild-type and mutant receptors in place of the endogenous receptor. These studies will provide insight into the molecular basis for the cellular responses to hallucinogenic chemicals elicited at the 5-HT/2A receptor and may facilitate the development of new therapeutic modalities.