Does neurokinin-1 modulate amphetamine reward via catecholamine transport?

 描述（由申请人提供）：目前，没有经过验证的药物来治疗兴奋剂滥用，成瘾或复发。因此，新知识的神经基板，修改精神兴奋剂药物将大大有助于确定新的目标，开发治疗策略，干预这些过程。改变的去甲肾上腺素能传递和突触前去甲肾上腺素转运体（NET）的表达一直与抑郁症和药物成瘾。事实上，安非他明（AMPH）的目标NET和下调其功能。我们已经证明AMPH通过转运蛋白T258/S259运输基序下调NET功能和表面表达。我们还表明，激活的神经激肽-1受体（NK 1 R）负调节NET通过PKC磷酸化相同的主题。这些发现具有生理学意义，因为（i）物质P，内源性NK 1 R激动剂，在AMPH治疗后释放。SP增强AMPH刺激作用，而NK 1 R拮抗剂阻断这种作用;（ii）NK 1 R敲除小鼠表现出ADHD样表型;和（iii）AMPH是用于治疗人类ADHD的治疗剂。因此，NET、NK 1 R和AMPH之间显然存在生理相关关系。在这方面，我们发现NK 1 R和AMPH都介导NET下调，并且都与T258/S259基序相关，这表明该途径可能在调节AMPH引起的行为中起重要作用。作为支持，我们的初步体内研究表明，AMPH诱导的NET下调和运动激活对NK 1 R拮抗剂和靶向T258/S259基序的操纵敏感。我们提出了两个具体的目标来验证我们的假设，即NK 1 R介导的T258/S259特异性NET下调有助于AMPH行为效应。目的1验证NK 1 R介导AMPH诱导的小鼠NET调节和奖赏样行为的假设。我们将确定腹侧纹状体NK 1 R在调制AMPH诱导的突触NET调节和条件性位置偏爱的作用，通过脑核特异性显微注射激动剂和拮抗剂单独或组合。目的二是验证NET T258/S259基序是AMPH介导的奖励样行为和NET下调所必需的假设。我们将研究T258/S269基序的作用，通过腹侧纹状体显微注射细胞可渗透的TAT-NET肽，干扰AMPH依赖的NET运输。由于多巴胺转运蛋白（DAT）也被NK 1 R和AMPH下调，并且NET和DAT在T258/S259区域具有高度保守的序列同源性，因此DAT-KO小鼠也将用于这两个目的，以将NET调节的作用与DAT的作用分离。了解NK 1 R如何调节胺转运蛋白可能有助于我们确定具体的机制，（这可能是治疗靶点），由此AMPH破坏儿茶酚胺转运蛋白功能，从而破坏动物行为。

 DESCRIPTION (provided by applicant): Currently, there are no proven medications to treat stimulant abuse, addiction or relapse. Therefore, new knowledge on the neuronal substrates that are modified by psychostimulant drugs will greatly aid in identifying novel targets for developing therapeutic strategies to intervene in these processes. Altered noradrenergic transmission and presynaptic norepinephrine transporter (NET) expression have long been associated with depression and drug-addiction. Indeed, amphetamine (AMPH) targets NET and downregulates its function. We have shown that AMPH downregulates NET function and surface expression via transporter T258/S259 trafficking motif. We have also shown that activation of the neurokinin-1 receptor (NK1R) negatively regulates NET via PKC phosphorylation of the same motif. These findings are of physiological significance because (i) Substance P, the endogenous NK1R agonist, is released following AMPH treatment. SP enhances AMPH stimulant effects, whereas NK1R antagonists block this effect; (ii) NK1R knockout mice exhibit ADHD-like phenotype; and (iii) AMPH is a therapeutic agent for treating ADHD in the human. Thus, there is, apparently a physiologically relevant relationship between NET, NK1R and AMPH. In this regard, our discovery that both NK1R and AMPH mediate NET downregulation and that both are linked to the T258/S259 motif suggests that this pathway may play a significant role in regulating AMPH-elicited behaviors. In support, our preliminary in vivo studies suggest that AMPH-induced NET downregulation and locomotor activation are sensitive to NK1R antagonists and to manipulations targeting the T258/S259 motif. We propose two specific aims to test our hypothesis that the NK1R-mediated T258/S259-specific NET downregulation contributes to AMPH behavioral effects. Aim 1 will test the hypothesis that NK1R mediates AMPH-induced NET regulation and reward-like behavior in mice. We will identify the role of ventral striatal NK1R in modulating AMPH-induced synaptic NET regulation and conditioned place preference by brain nuclei-specific microinjections of agonists and antagonists alone or in combination. Aim 2 will test the hypothesis that NET T258/S259 motif is required for AMPH-mediated reward-like behavior and NET downregulation in mice. We will study the role of the T258/S269 motif by ventral striatal microinjections of cell permeable TAT-NET peptides that interfere with the AMPH-dependent trafficking of NET. Since dopamine transporter (DAT) is also downregulated by both NK1R and AMPH, and both NET and DAT share highly conserved sequence homology at the T258/S259 region, DAT-KO mice will also be utilized in both aims to dissociate the role of NET regulation from that of DAT. Thus, understanding how NK1R regulates amine transporters may help us identify the specific mechanisms (which could be therapeutic targets) whereby AMPH disrupts catecholamine transporter function and hence animal behavior.