STRIATAL PHOSPHOPROTEINS AND THE ACTIONS OF PSYCHOSTIMULANTS

大量证据表明，精神兴奋剂（如可卡因和 安非他明）以及其他滥用药物的作用，涉及中脑边缘神经传递的调节， 黑质纹状体多巴胺系统我们以前的研究表明，一个家族的底物cAMP依赖 蛋白激酶，包括DARPP-32、RCS（钙调蛋白信号调节剂，以前称为ARPP-21），和 ARPP-16在基底神经节中高度富集，包括新纹状体和丘脑核。以前的研究 已经表明DARPP-32的一个关键靶点是丝氨酸/苏氨酸蛋白磷酸酶PPL。 已经发现RCS与钙结合蛋白钙调素相互作用，并反过来调节丝氨酸/苏氨酸 蛋白磷酸酶、钙调磷酸酶（或PP 2B）。在其他研究中，我们发现ARPP-16很可能调节 GAP-43 mRNA的稳定性。在项目III中，我们建议研究RCS和ARPP-16在调解或 调节精神兴奋剂的作用此外，我们建议研究PP 1的三种异构体的作用， （PP 1 α，β和γ）在精神兴奋剂的作用。具体目标是： 目的I：RCS的表征-我们将在RCS敲除小鼠中分析动物行为的几个方面， 由精神兴奋剂调节的生理学。这些研究将包括急性和慢性运动兴奋剂 可卡因和安非他明在RCS突变小鼠中的特性和药物强化特性。我们还将描述 RCS的分子靶点，可能参与介导精神兴奋剂的作用。研究将包括 RCS和钙调磷酸酶调节的分析，以及RCS和其他钙调蛋白结合蛋白调节的分析。 目的II：ARPP-16的特性研究--我们将在ARPP-16基因敲除小鼠中分析ARPP-16基因的几个方面的动物特性， 由精神兴奋剂调节的行为和生理。这些研究将包括急性和慢性运动兴奋剂 可卡因和安非他明在RCS突变小鼠中的特性和药物强化特性。我们还将 表征ARPP-16通过新位点磷酸化的调节，并研究这些位点的磷酸化， 对精神兴奋剂治疗的反应 目的III：PP 1亚型的表征-我们将研究PP 1 α，β和γ亚型在以下作用中的作用： 精神兴奋剂这些将包括急性和慢性运动兴奋特性和药物强化特性， 可卡因和安非他明的作用。 我们的研究成果将补充本计划项目赠款的其他项目。这些研究将 希望能够阐明滥用药物在大脑中作用的生化途径，并 增加了开发治疗剂的可能性，该治疗剂将防止或逆转体内的分子适应， 这些途径。

Considerable evidence indicates that the acute and chronic actions of psychomotor stimulants (e.g. cocaine and amphetamine), as well as of other drugs of abuse, involve modulation of neurotransmission in mesolimbic and nigrostriatal dopamine systems. Our previous studies have revealed that a family of substrates for cAMP-dependent protein kinase, including DARPP-32, RCS (Regulator of Calmodulin Signaling, previously termed ARPP-21), and ARPP-16, are highly enriched in the basal ganglia, including the neostriatum and nucleus accumbens. Previous studies have indicated that a critical target for DARPP-32 is the serine/threonine protein phosphatase, PPL In recent studies we have found that RCS interacts with the Ca2+-binding protein calmodulin and in turn regulates the serine/threonine protein phosphatase, calcineurin (or PP2B). In other studies, we have found that ARPP-16 is likely to regulate the stability of GAP-43 mRNA. In Project III, we propose to study the role(s) of RCS and ARPP-16 in mediating or modulating the actions of psychostimulants. In addition, we propose to study the roles of the three isoforms of PP1 (PP1alpha, beta and gamma) in the actions of psychostimulants. The Specific Aims are: Aim I: Characterization of RCS - We will analyze in RCS knockout mice, several aspects of animal behavior and physiology that are modulated by psychostimulants. These studies will include acute and chronic motor-stimulant properties and drug reinforcing properties of cocaine and amphetamine in RCS mutant mice. We will also characterize molecular targets for RCS that may be involved in mediating the actions of psychostimulants. Studies will include analysis of RCS and regulation of calcineurin, and of RCS and regulation of other calmodulin-binding proteins. Aim II: Characterization of ARPP-16 - We will analyze in ARPP-16 knockout mice, several aspects of animal behavior and physiology that are modulated by psychostimulants. These studies will include acute and chronic motorstimulant properties and drug reinforcing properties of cocaine and amphetamine in RCS mutant mice. We will also characterize the regulation of ARPP-16 by phosphorylation at novel sites and study the phosphorylation of these sites in response to psychostimulant treatment. Aim III: Characterization of PP1 isoforms - We will investigate the role of PP1alpha, beta and gamma isoforms in the actions of psychostimulants. These will include acute and chronic motor-stimulant properties and drug reinforcing properties of cocaine and amphetamine in RCS mutant mice. Results from our studies will complement other Projects of this Program Project grant. Together, these studies will hopefully lead to elucidation of the biochemical pathways through which drugs of abuse act in the brain, and to an increased likelihood that therapeutic agents will be developed that will prevent or reverse molecular adaptations within these pathways.