SEROTONIN RECEPTOR SUBTYPES--REGULATION & INTERACTION

大脑中受体的调节在解释某些 精神治疗药物的影响。 从历史上看， 监管的重点是长期暴露不足或过度暴露的影响 神经递质的受体。 受体的调节和 反应也可能通过受体亚型之间的相互作用发生 特定的神经递质。 本报告的总体目标 建议是调查5-HT 1A和 5-HT 2受体参与其调节。 治疗结果 在5-HT 1A受体介导反应的脱敏中， 5-HT 2受体数量和/或5-HT 2受体介导的敏感性 应答 第一个具体目标中提出的研究旨在 利用培养的细胞， 第二信使系统之间的联系， 有助于调节现象。 蛋白激酶C的激活， 第二信使系统的组成部分，5-HT 2受体 偶联，导致5-HT 1A受体的脱敏。 因此，在本发明中， 5-HT_2受体激活可能在脑缺血再灌注损伤的脱敏中起作用。 5-HT 1A受体。 P11细胞，其表达5-HT 2受体， 磷酸肌醇（PI）水解，将用5-HT 1A转染 为了研究这些血清素之间的相互作用， 受体亚型和它们各自的第二信使系统 相同单元 5-HT 2受体的激活是否导致脱敏 5-HT 1A受体介导的对毛喉素刺激的腺苷酸的抑制 将测定环化酶和/或5-HT 1A受体结合的变化。 腺苷酸环化酶级联激活对5-HT 2的影响 受体刺激的PI水解和5-HT 2受体结合也将 追究 P11细胞5-HT 1A受体的调节 表达两种5-羟色胺受体亚型的小鼠， 中国卵巢癌（CHO）细胞中的调控，转染以表达 只有5-HT 1A受体。 在第二个具体目标中， 建议在体内测试5-HT 1A受体的调节是否 由于5-HT 2受体的激活而发生，或由于 5-HT 2受体的脱敏或下调，以及是否 这需要完整的多巴胺能神经元。 大鼠将 接受5-HT 2受体激动剂DOI的单次注射，或 注射拮抗剂米安色林，或用5-羟色胺长期治疗， HT 2受体拮抗剂酮色林。 DOI治疗导致激活 5-HT 2受体的表达，但在此期间5-HT 2受体没有下调 何时进行测量。 相比之下，这些治疗 拮抗剂已显示下调5-HT 2受体。 的 两种血清素受体亚型的敏感性和功能将被 在同一动物和同一大脑区域进行评估，特别是 5-HT 1A受体介导的皮质腺苷酸环化酶抑制 匀浆和5-HT_2受体刺激皮质PI水解 切片 这种综合办法应提供重要信息， 不仅有助于我们理解 5-羟色胺受体亚型及其各自的第二信使系统 而且也是体内5-HT 1A受体的调节。

The regulation of receptors in brain is important in explaining certain effects of psychotherapeutic drugs. Historically, studies of receptor regulation have focused on the effect of chronic under- or over-exposure of a receptor to its neurotransmitter. The regulation of receptors and responses may also occur through interactions between receptor subtypes for a particular neurotransmitter. The overall objective of this proposal is to investigate whether interactions between the 5-HT1A and 5-HT2 receptors are involved in their regulation. Treatments that result in a desensitization of 5-HT1A receptor-mediated responses also regulate 5-HT2 receptor number and/or the sensitivity of 5-HT2 receptor-mediated responses. The studies proposed in the first specific aim are designed to explore, using cells maintained in culture, whether interactions between the second messenger systems linked to each subtype occur and contribute to regulatory phenomena. Activation of protein kinase C, an integral part of the second messenger system to which the 5-HT2 receptor is coupled, leads to the desensitization of the 5-HT1A receptor. Thus, 5-HT2 receptor activation may play a role in the desensitization of the 5-HT1A receptor. P11 cells, which express 5-HT2 receptors coupled to phosphoinositide (PI) hydrolysis, will be transfected with the 5-HT1A receptor in order to study the interactions between these serotonin receptor subtypes and their respective second messenger systems on the same cell. Whether activation of 5-HT2 receptors causes desensitization of 5-HT1A receptor-mediated inhibition of forskolin-stimulated adenylyl cyclase and/or changes in 5-HT1A receptor binding will be determined. The effect of activation of the adenylyl cyclase cascade on 5-HT2 receptor stimulated PI hydrolysis and 5-HT2 receptor binding will also be investigated. The regulation of 5-HT1A receptors in P11 cells expressing both serotonin receptor subtypes will be compared to its regulation in Chinese Hamster Ovary (CHO) cells, transfected to express only the 5-HT1A receptor. In the second specific aim, studies are proposed to test in vivo whether the regulation of 5-HT1A receptors occurs as a result of activation of 5-HT2 receptors, or as a result of the desensitization or down regulation of 5-HT2 receptors and whether intact serotonergic neurons are required for this to occur. Rats will receive a single injection of the 5-HT2 receptor agonist DOI, or single injection of the antagonist mianserin, or chronic treatment with the 5- HT2 receptor antagonist ketanserin. Treatment with DOI causes activation of 5-HT2 receptors but no down regulation of 5-HT2 receptors at the time when measurements will be done. By contrast, these treatments with antagonists have been shown to down regulate 5-HT2 receptors. The sensitivity and function of both serotonin receptor subtypes will be assessed in the same animal and in the same brain region, specifically 5-HT1A receptor-mediated inhibition of adenylyl cyclase in cortical homogenates and 5-HT2 receptor stimulated PI hydrolysis in cortical slices. This combined approach should provide important information that will contribute to our understanding not only of the interactions between serotonin receptor subtypes and their respective second messenger systems but also of the regulation of the 5-HT1A receptor in vivo.