Ho Jianghai, Perez-Aguilar Jose Manuel, Gao Lu, Saven Jeffery G, Matsunami Hiroaki, Eckenhoff Roderic G
Department of Molecular Genetics and Microbiology, and Department of Neurobiology, Duke University, Durham, NC 27710, USA.
Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
Sci Signal. 2015 Mar 31;8(370):ra33. doi: 10.1126/scisignal.2005912.
Ketamine elicits various neuropharmacological effects, including sedation, analgesia, general anesthesia, and antidepressant activity. Through an in vitro screen, we identified four mouse olfactory receptors (ORs) that responded to ketamine. In addition to their presence in the olfactory epithelium, these G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors (GPCRs) are distributed throughout the central nervous system. To better understand the molecular basis of the interactions between ketamine and ORs, we used sequence comparison and molecular modeling to design mutations that (i) increased, reduced, or abolished ketamine responsiveness in responding receptors, and (ii) rendered nonresponding receptors responsive to ketamine. We showed that olfactory sensory neurons (OSNs) that expressed distinct ORs responded to ketamine in vivo, suggesting that ORs may serve as functional targets for ketamine. The ability to both abolish and introduce responsiveness to ketamine in GPCRs enabled us to identify and confirm distinct interaction loci in the binding site, which suggested a signature ketamine-binding pocket that may guide exploration of additional receptors for this general anesthetic drug.
氯胺酮会引发多种神经药理学效应，包括镇静、镇痛、全身麻醉和抗抑郁活性。通过体外筛选，我们鉴定出了四种对氯胺酮有反应的小鼠嗅觉受体（OR）。除了存在于嗅觉上皮中，这些G蛋白（异三聚体鸟嘌呤核苷酸结合蛋白）偶联受体（GPCR）还分布于整个中枢神经系统。为了更好地理解氯胺酮与OR之间相互作用的分子基础，我们使用序列比较和分子建模来设计突变，这些突变能够：（i）增强、降低或消除有反应的受体对氯胺酮的反应性，以及（ii）使无反应的受体对氯胺酮产生反应。我们发现，表达不同OR的嗅觉感觉神经元（OSN）在体内对氯胺酮有反应，这表明OR可能是氯胺酮的功能靶点。在GPCR中消除和引入对氯胺酮反应性的能力使我们能够识别并确认结合位点中不同的相互作用位点，这提示了一个标志性的氯胺酮结合口袋，可能有助于探索这种全身麻醉药物的其他受体。
