Serotonin receptors that potentiate addiction-related behavioral and molecular effects induced by methylphenidate plus SSRI exposure

项目摘要/摘要： 许多人暴露在药物组合中，包括哌醋甲酯(利他林)和一种 选择性5-羟色胺再摄取抑制剂(SSRI)。这种药物组合被认为是注意力缺陷的征兆。 多动障碍(ADHD)/抑郁或焦虑共病(高达40%的儿童ADHD)和其他 精神障碍。例如，高剂量联合暴露也发生在滥用SSRIs的患者中 哌醋甲酯是一种“认知增强剂”或派对药物。这些研究对象中有许多是儿童或青少年。 这是一个公共卫生问题，因为潜在的长期行为和神经元变化是由 这些精神药物。单独服用哌醋甲酯(一种多巴胺/去甲肾上腺素再摄取抑制剂)， 模仿可卡因的一些分子效应，但不是其他分子效应。这些影响不那么强劲，大概是因为 哌醋甲酯不影响5-羟色胺系统。事实上，申请者实验室的研究表明 SSRI联合哌醋甲酯治疗可加强与滥用/成瘾相关的行为，并 基因调控，从而产生“类似可卡因”的行为和分子特征。目前尚不清楚是哪种血清素 受体亚型(S)介导这些SSRI(5-羟色胺)效应。这个项目的长期目标是更好地 了解5-羟色胺和多巴胺如何相互作用，以诱导它们对药物成瘾相关行为的影响 神经突起。这项应用的目的是确定5-羟色胺受体亚型和细胞类型 介导了哌醋甲酯和SSRI联合应用对可卡因和 青春期雄性和雌性大鼠纹状体和伏隔核的基因调控。中环 假设是SSRI增强了哌甲酯对可卡因诱导的行为和基因的影响 通过激活特定的5-羟色胺受体亚型进行调节。这一假设是基于初步数据。 来自申请者的实验室。拟议工作的理由是有必要确定所涉及的 5-羟色胺受体亚型和神经元种群，为鉴定新的 避免这些影响的药物干预。核心假设将通过追求三个方面来检验 具体目标：1)确定联合应用哌醋甲酯和SSRI的行为和神经元后果 (氟西汀)治疗，比较临床相关剂量和“滥用剂量”；2)测定5-羟色胺受体 对行为和基因调控有贡献的亚型；3)确定 调节这些行为和分子变化的大脑部位和细胞群。对行为的影响将 使用可卡因诱导的位置偏爱条件反射(CPP)和敏化模型来确定。 对基因调控的影响将通过原位杂交、RT-qPCR和Western印迹分析来评估。 这些技术在我们的实验室中已经很成熟了。这项拟议的研究意义重大，因为澄清 5-羟色胺增强精神刺激剂诱导的行为和神经元变化的机制将 为避免这些潜在健康风险的新型抗抑郁药物的未来发展提供信息。

Project Summary/Abstract: Scores of people are being exposed to drug combinations that include methylphenidate (Ritalin) plus a selective serotonin reuptake inhibitor (SSRI). Such drug combinations are indicated for attention-deficit hyperactivity disorder (ADHD)/depression or anxiety comorbidity (in up to 40% of pediatric ADHD) and other psychiatric disorders. High-dose co-exposure also occurs, for example, in patients on SSRIs who abuse methylphenidate as a “cognitive enhancer” or party drug. Many of these subjects are children or adolescents. This is a public health concern because of potential long-term behavioral and neuronal changes induced by these psychotropic drugs. Methylphenidate (a dopamine/norepinephrine reuptake inhibitor), given alone, mimics some, but not other, molecular effects of cocaine. These effects are less robust presumably because methylphenidate does not affect serotonin systems. Indeed, research in the applicants' laboratories shows that treatment with an SSRI in conjunction with methylphenidate potentiates abuse/addiction-related behavior and gene regulation, thus producing “cocaine-like” behavioral and molecular profiles. It is unknown which serotonin receptor subtype(s) mediate these SSRI (serotonin) effects. The long-term goal of this project is to better understand how serotonin and dopamine interact to induce their effects on drug addiction-related behavior and neuronal processes. The objective of this application is to determine serotonin receptor subtypes and cell types that mediate the effects of methylphenidate plus SSRI combinations on behavioral responses to cocaine and gene regulation in striatum and nucleus accumbens in adolescent male and female rats. The central hypothesis is that SSRIs potentiate methylphenidate effects on both cocaine-induced behavior and gene regulation via activation of specific serotonin receptor subtypes. This hypothesis is based on preliminary data from the applicants' laboratories. The rationale for the proposed work is the necessity to determine the involved serotonin receptor subtypes and neuron populations, in order to lay the groundwork for identifying novel pharmacological interventions that avoid these effects. The central hypothesis will be tested by pursuing three specific aims: 1) Determine behavioral and neuronal consequences of combined methylphenidate+SSRI (fluoxetine) treatment, comparing clinically relevant doses and “abuse doses”; 2) Determine serotonin receptor subtypes that contribute to the methylphenidate+SSRI effects on behavior and gene regulation; 3) Determine brain sites and cell populations that mediate these behavioral and molecular changes. Effects on behavior will be determined using the cocaine-induced place preference conditioning (CPP) and sensitization models. Effects on gene regulation will be assessed by in situ hybridization, RT-qPCR, and Western blot analyses. These techniques are well-established in our labs. The proposed research is significant, because elucidating the mechanisms by which serotonin potentiates psychostimulant-induced behavioral and neuronal changes will inform the future development of novel antidepressants that avoid these potential health risks.