SLEEP/DOPAMINE PHENOTYPES IN GENETICALLY DISTINCT MICE

描述(根据申请者的缺席改编)一个知之甚少的状态神经调节器是中纹状体多巴胺(DA)系统，它不仅促进动机/奖励和运动，而且还促进唤醒(即觉醒)。相反，DA阻断和阻断中纹状体通路会减慢运动速度并促进嗜睡。中纹状体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。昼夜节律和稳态觉醒/睡眠因素影响中纹状体环路的可塑性，但它们的功能意义也不明确。具有多巴胺转运蛋白基因缺失(DAT-/-)的小鼠、其杂合子(DAT+/-)、野生型窝仔、转基因衍生的纯C57BL/6和S129/SV品系，以及已知中纹状体D2受体低表达的DBA/2近交系小鼠，为探索DA在状态控制中的作用，并解释觉醒/睡眠表型的遗传变异提供了一种手段。目的#1建议描述这些小鼠的24小时运动活动模式与睡眠/清醒结构的关系。DAT-/-和DAT+/-在主观夜间的运动多动导致主观白天的活动不足，这表明面对慢性升高的突触DA，睡眠/觉醒反转(初步数据)。动态平衡睡眠动力强大到足以克服慢性DA升高的机制--如果睡眠确实存在观察到的低活动--可能存在于参与中纹状体DA传递的其他蛋白质中。因此，Aim#2建议测量传统的DA标记物，并在分子上定义的D1受体、DAT和囊泡单胺转运体(VMAT2)在边缘和运动纹状体回路24小时内的表达，以加强对Aim#1发现的解释。目的#3研究物理方法、安非他酮(DAT阻滞剂)和咖啡因(腺苷受体阻滞剂)诱导的长时间觉醒对这些小鼠中脑纹状体DA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独特的昼夜节律，这些蛋白质介导DA神经传递，以及这些蛋白质对长时间觉醒的独特反应，这可能是特定于治疗方式的，与抑郁症患者对快速眼动睡眠剥夺的反应不同的方式很相似，发作性睡病患者和抑郁症患者对DAT阻断的快速眼动睡眠反应不同。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过程和治疗的理解，这些疾病的病理生理学植根于DA敏感的基底节回路。

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.