SLEEP/DOPAMINE PHENOTYPES IN GENETICALLY DISTINCT MICE

描述（改编自申请人摘要）一个鲜为人知的神经状态调节剂是中纹状体多巴胺（DA）系统，它不仅促进动机/奖励和运动，还促进觉醒（即清醒）。相反，DA的阻断和中纹状体通路的中断会减缓运动并促进嗜睡。中间纹状体DA对觉醒/睡眠节律、睡眠结构以及所涉及的细胞和亚细胞底物的影响的细节仍不清楚。昼夜节律和体内平衡唤醒/睡眠因素影响中纹状体回路的可塑性，但其功能的重要性也不明确。多巴胺转运体（DAT-/-）基因缺失的小鼠、它们的杂合子（DAT+/-）、野生型幼鼠、转基因衍生的纯C57BL/6和S129/sv菌株，以及已知中纹状体D2受体表达不足的DBA/2近交系，为探索DA在状态控制中的作用以及解释清醒/睡眠表型的遗传变异提供了一种手段。目的1提出表征与这些小鼠睡眠/觉醒结构相关的24小时运动活动模式。在主观夜间，DAT -/-和DAT +/-的运动亢进转化为主观白天的低活动，这表明面对长期升高的突触DA时，睡眠/觉醒逆转（初步数据）。如果睡眠确实与观察到的低活跃性有关，那么足以克服慢性DA升高的体内平衡睡眠驱动的机制可能存在于参与中体纹状体DA传递的其他蛋白质中。因此，Aim #2建议在24小时内测量传统的DA标记物、分子定义的D1受体、DAT和囊泡单胺转运蛋白（vMAT2）在边缘和运动纹状体回路中的表达，以加强对Aim #1研究结果的解释。目的3研究通过物理方法，安非他酮（一种数据阻滞剂）和咖啡因（一种腺苷受体阻滞剂）诱导的长时间清醒对这些小鼠中纹状体数据阻滞剂系统的影响。研究人员推测，这些转基因和近亲繁殖的小鼠将表现出介导DA神经传递的蛋白质的独特昼夜节律，以及这些蛋白质对长时间清醒的独特反应，这可能是治疗方式特异性的，就像抑郁症患者对快速眼动睡眠剥夺的反应不同，发作性睡症患者与抑郁症患者对DAT阻断的快速眼动睡眠反应不同一样。综上所述，这些发现将促进对状态如何调节失眠、抑郁和神经精神疾病的病程和治疗的理解，这些疾病的病理生理学根源于DA敏感的基底神经节回路。

DESCRIPTION (adapted from the applicants' absract) One poorly understood neuromodulator of state is the mesostriatal dopamine (DA) system, which not only promotes motivation/reward and movement, but also arousal (viz., wakefulness). Conversely, DA blockade and interruption of mesostriatal pathways slows movement and promotes sleepiness. The details of mesostriatal DA's effects upon wake/sleep rhythms, and sleep architecture, and the cellular and subcellular substrates involved remain poorly defined. Circadian and homeostatic wake/sleep factors affect mesostriatal circuit plasticity, but their functional import is also undefined. Mice with genetic deletions of the dopamine transporter (DAT-/-), their heterozygotes (DAT+/-), wild type littermates, the pure C57BL/6 and S129/sv strains from which the transgenics derive, and the DBA/2 inbred strain with known under expression of mesostriatal D2 receptors afford a means to probe DA's role in state control, and to account for genetic variation in wake/sleep phenotypes. Aim #1 proposes to characterize 24-hour motor activity patterns in relation to sleep/wake architecture in these mice. Motor hyperactivity in DAT -/- and DAT +/- during the subjective night yields to hypoactivity during subjective day suggesting a sleep/wake reversal in the face of chronically elevated synaptic DA (preliminary data). The mechanisms underlying a homeostatic sleep drive powerful enough to overcome chronic DA elevations - if indeed sleep attends the observed hypoactivity - may reside in other proteins involved in mesostriatal DA transmission. Aim #2 therefore proposes to measure traditional DA markers, and molecularly defined D1 receptor, DAT and vesicular monoamine transporter (vMAT2) expression across 24-hours in limbic and motor striatal circuits to enhance interpretation of Aim #1 findings. Aim #3 investigates the effects of prolonged wakefulness induced by physical means, bupropion (a DAT blocker), and caffeine (an adenosine receptor blocker), on the mesostriatal DA system in these same mice. The investigators postulate that these transgenic and inbred mice will exhibit unique circadian rhythms of proteins mediating DA neurotransmission and unique responses of these proteins to prolonged wakefulness that may be treatment modality specific, much the same way that depressives differ in their response to REM-sleep deprivation, and narcoleptics differ from depressives in their REM-sleep responses to DAT blockade. Taken together, the findings will advance an understanding of how state might modulate the course and treatment of insomnia, depression, and neuropsychiatric diseases whose pathophysiologies are rooted in DA sensitive basal ganglia circuits.