Project 3: Elucidation of Biochemical and Behavioral Efficacies of Antipsychotics

具体目标 在经典药理学中，激动剂激活单一的线性信号转导通路，而 拮抗剂阻断激动剂的作用，不具有内在活性。在过去的几年里，它已经 很明显，信号转导通路不仅仅是信号的线性级联。相反，他们是 组织成复杂的信令网络，需要高级别的监管才能产生精确和独特的 细胞反应。因此，一个给定的受体，通过各种配体诱导的功能构象，可以 通过与不同的信令合作伙伴互动，参与多种医疗模式。通过这种方式，给定的配体可以 结合受体并在一条信号通路上充当拮抗剂，同时在另一条或另一条信号通路上充当激动剂 对白。这一特性是针对几种G蛋白偶联受体(GPCRs)建立的--最重要的 治疗干预的靶点。重要的是，临床上使用的药物中没有一种是用 请记住这些多重信令考虑因素。此外，激动剂和拮抗剂很少完全 选择性的，对于给定的受体，可以通过影响各种受体介导的过程来改变信号转导，如 AS与G蛋白的相互作用、脱敏、内化、下调和受体介导 非G蛋白信号成分的支架。不幸的是，这些生物的生理相关性 房地产并没有得到充分的重视。因此，确定化合物的功能选择性可能有助于揭示 不仅是不同的生物过程，而且还有特定的功能结果。目前，职能部门的相关性 对精神病学的选择性是未知的。这对抗精神病药物尤其重要，其中多巴胺(DA) D2受体(D2R)拮抗本质上是所有这些药物的先决条件；然而，它们的其他内在 活动很隐晦。这项拟议的研究的总体目标是检查对 并阐明抗精神病药物的信号转导机制。 临床前遗传学和药理学类精神分裂症小鼠模型的抗精神病疗效 行为。对于行为，抗精神病药物对运动活动、脉搏前抑制(PPI)、潜伏期的影响 抑制(LI)和DA转运体(DAT)敲除(KO)，N-甲基-D-天冬氨酸(NMDA)的社会行为 受体NR1亚单位敲除(KD)和苯丙胺或苯环利定对C57BL/6小鼠的影响 (PCP)复制精神分裂症样状态。信号转导通路的分子指纹图谱 (MFSTP)将分析抗精神病化合物对各种信号转导的影响 包括蛋白激酶A(PKA)和多巴胺(DA)以及cAMP调节的磷酸蛋白32(DARPP- 32)，Akt/蛋白激酶B(PKB或Akt)和糖原合成酶激酶33(GSK3)，磷脂酶C(PLC)，以及 细胞外信号调节的丝裂原活化蛋白激酶(ERK)通路。目前的实验 项目3将通过提供临床前模型来测试体内试验，从而补充项目1和项目2中的模型 不同抗精神病药物改善精神分裂症样行为的选择性和有效性 并将这些反应与信号转导中的变化联系起来。我们的项目#3也将补充 惠氏的核心项目，将分析精神分裂症样大鼠模型的抗精神病反应 抗精神病药物治疗的行为。了解抗精神病药物功能选择性的相关性 可以提供副作用更少、治疗选择性更强、疗效更好的新靶点 治疗精神分裂症患者。我们的项目#3有三个具体目标。 目的1.高多巴胺痛在DAT-KO小鼠对抗精神病药物反应中的作用。 比较DAT-KO小鼠对不同抗精神病药物的行为反应。 B.将MFSTP应用于不同脑区，以确定高多巴胺能表型并分析 对抗精神病药物的反应。 目的II.NMDA受体表达减少在NR1-KD小鼠抗精神病药物反应中的作用。 比较NR1亚型小鼠对不同抗精神病药物的行为反应。 B.将MFSTP应用于不同脑区以确定NMDA受体亚型的表型 并分析对抗精神病药物化合物的反应。 目的III.药物诱导的高多巴胺痛或低谷氨酸血症在对 抗精神病药物在C57BU6小鼠中的应用。 A.比较AMPH或PCP治疗的小鼠对不同抗精神病药物的行为反应。 B.将MFSTP应用于不同的大脑区域，以确定药物诱导的多巴胺能或 低谷氨酸能状态，并分析抗精神病药物的反应。

SPECIFIC AIMS In classical pharmacology, an agonist activates a single linear signal transduction pathway, whereas an antagonist blocks the action of the agonist and possesses no intrinsic activity. Over the past few years, it has become clear that signal transduction pathways are not merely linear cascades for signaling. Instead, they are organized into complex signaling networks that require high levels of regulation to generate precise and unique cellular responses. Hence, a given receptor, through various ligand-induced functional conformations, can engage multiple modalities through interaction with different signaling partners. In this way, a given ligand can bind a receptor and act as an antagonist for one signaling pathway while serving as an agonist at another or the converse. This property is established for several G protein-coupled receptors (GPCRs) - the most important targets for therapeutic intervention. Importantly, none of the drugs in clinical use have been developed with these multiple signaling considerations in mind. Additionally, agonists and antagonists are rarely completely selective and, for a given receptor, may alter signaling by influencing various receptor-mediated processes such as interaction with G proteins, desensitization, internalization, down-regulation, and receptor-mediated scaffolding of non-G protein signaling components. Unfortunately, the physiological relevance of these properties is not fully appreciated. Thus, identifying the functional selectivity of compounds may help reveal not only distinct biological processes, but also specific functional outcomes. Currently, the relevance of functional selectivity to psychiatry is unknown. This is particularly important for antipsychotic drugs, where dopamine (DA) D2 receptor (D2R) antagonism is essentially a prerequisite for all these drugs; however, their other intrinsic activities are obscure. The overall goal of the proposed research is to examine behavioral responses to antipsychotic compounds and to elucidate signal transduction mechanisms that are essential for antipsychotic efficacy in preclinical genetic and pharmacological mouse models of schizophrenia-like behaviors. For behavior, effects of antipsychotic compounds on motor activity, prepulse inhibition (PPI), latent inhibition (LI), and social behavior in DA transporter (DAT) knockout (KO), N-methyl-D-aspartate (NMDA) receptor NR1-subunit knockdown (KD), and C57BL/6 mice treated with amphetamine (AMPH) or phencyclidine (PCP) to reproduce schizophrenia-like states. Molecular fingerprinting of signal transduction pathways (MFSTP) will be performed to analyze effects of antipsychotic compounds on various signal transduction modalities that include the protein kinase A (PKA) and DA and cAMP-regulated phosphoprotein 32 (DARPP- 32), Akt/protein kinase B (PKB or Akt) and glycogen synthase kinase 33 (GSK3), phospholipase C (PLC), and extracellular signal-regulated mitogen activated protein kinase (ERK) pathways. The experiments in the present Project #3 will complement those in Projects #1 and #2 by providing preclinical models to test the in vivo selectivities and efficacies of various antipsychotic compounds on amelioration of schizophrenia-like behaviors and will correlate these responses to alterations in signal transduction. Our Project #3 will complement also the Core Project from Wyeth where antipsychotic responses will be analyzed in rat models of schizophrenia-like and antipsychotic-treated behaviors. Understanding the relevance of functional selectivity of antipsychotic drugs may provide novel targets with fewer side-effects, greater therapeutic selectivity, and enhanced efficacy for treating individuals with schizophrenia. Our Project #3 has three Specific Aims. Aim I. Role of hyperdopaminergia in responses to antipsychotic compounds in DAT-KO mice. A. To compare behavioral responses of DAT-KO mice to different antipsychotic compounds. B. To apply MFSTP to various brain regions to define the hyperdopaminergic phenotype and analyze responses to antipsychotic compounds. Aim II. Role of reduced NMD A receptor expression in responses to antipsychotics in NR1-KD mice. A. To compare behavioral responses of NR1 hypomorphic mice to different antipsychotic compounds. B. To apply MFSTP to various brain regions to define the phenotype of the NMDA receptor hypomorphic mice and analyze responses to antipsychotic compounds. Aim III. Roles of pharmacologically-induced hyperdopaminergia or hypoglutamatergia in responses to antipsychotic compounds in C57BU6 mice. A. To compare behavioral responses of mice treated with AMPH or PCP to different antipsychotics. B. To apply MFSTP to various brain regions to define pharmacologically-induced hyperdopaminergic or hypoglutamatergic states and analyze responses to antipsychotic compounds.