Novel modulation of serotonin receptors

描述(由申请人提供)：调节gpr功能的新机制可能会导致许多疾病的治疗方法得到改进，包括精神分裂症和抑郁症。在这笔赠款的前一个资助周期中进行的研究显示，药物对h5-HT6和h5-HT7受体活性有两种意想不到的影响。1.已经发现了两组反向激动剂：一类是根据其与受体的亲和力预测的效力的高亲和力/高效力反向激动剂，另一类是根据其与受体的结合亲和力预测的效力远低于预测的“高亲和力/低效力”反向激动剂。2.第二个意想不到的结果是，利培酮(一种广泛使用的抗精神病药物)、9-OH-利培酮(利培酮的活性代谢物)和甲硫西平能迅速而有效地使天然h5-HT7受体(失活拮抗剂)失活。因此，这项建议涉及两个具体目标：1)确定高效力与低效力反向激动剂在CAMh5-HT6和5-HT7受体上的作用机制；2)确定导致利培酮快速而有效地灭活天然h5-HT7受体的作用机制(S)。具体目的“1将通过三种方式进行：a)对反向激动剂在CAM h5-HT6和h5-HT7受体上的作用进行详细的药理学分析，以确定是否可能涉及变构机制；b)监测反向激动剂对CAM h5-HT6和h5-HT7受体内化和β-arrestin易位的影响；c)监测反向激动剂对CAM h5-HT6和h5-HT7受体相关MARK活性的影响。具体目标2将通过三种方式实现：a)确定失活拮抗剂是否与完整细胞中的天然h-5HT7受体不可逆地相互作用；b)监测失活拮抗剂对天然h5-HT7受体内化和β-arrestin易位的影响；以及c)监测失活拮抗剂处理对表达天然h5-HT7受体的细胞中MARK活性的影响。这些研究结果可能揭示调节h5-HT6和h5-HT7受体功能状态的新机制，这可能适用于许多其他GPCR。这些调节机制的功能障碍可能是各种精神疾病的精神病理基础。这些研究可能会导致开发治疗包括精神分裂症和抑郁症在内的大脑功能障碍的新疗法。

DESCRIPTION (provided by applicant): Novel mechanisms of modulating GPCR function may result in improved therapeutics for treating many diseases including schizophrenia and depression. Studies performed during the previous funding cycle of this grant revealed two unexpected effects of drugs on h5-HT6 and h5-HT7 receptor activity. 1. Two groups of inverse agonists have been discovered: "high affinity/high potency" inverse agonists with potencies that are predicted from their affinities for the receptor, and "high affinity/low potency" inverse agonists with potencies that are far lower than predicted from their binding affinities for the receptor. 2.The second unexpected result is that risperidone (a widely prescribed antipsychotic drug), 9-OH-risperidone (the active metabolite of risperidone), and methiothepin produce a rapid and potent inactivation of the native h5-HT7 receptor (inactivating antagonists). Therefore, this proposal involves two specific aims: 1) determine the mechanism of action of high potency vs. low potency inverse agonists at CAM h5-HT6 and 5-HT7 receptors; and 2) determine the mechanism(s) of action that results in risperidone's rapid and potent inactivation of the native h5-HT7 receptor. Specific aim"1 will be approached in three ways: a) detailed pharmacological analysis of the actions of inverse agonists at the CAM h5-HT6 and h5-HT7 receptors to determine if an allosteric mechanism may be involved; b) monitor the effects of inverse agonists on CAM h5-HT6 and h5- HT7 receptor internalization and beta-arrestin translocation; c) monitor the effects of inverse agonists on CAM h5-HT6 and h5-HT7 receptor associated MARK activity. Specific aim 2 will be approached in three ways: a) determine if inactivating antagonists interact irreversibly with the native h-5HT7 receptor in intact cell preparations; b) monitor the effects of inactivating antagonists on native h5-HT7 receptor internalization and beta-arrestin translocation, and c) monitor the effects of inactivating antagonist treatment on MARK activity in cells expressing native h5-HT7 receptors. The results from these studies may reveal novel mechanisms for modulating the functional state of h5-HT6 and h5-HT7 receptors, which may be applicable to many other GPCR. Dysfunctions of these modulating mechanisms may underly the psychopathology of various mental diseases. These studies may lead to the development of novel therapeutics for brain dysfunctions, including schizophrenia and depression.