Mechanism of Dopaminergic Arousal

描述（由申请人提供）：多种滥用药物，尤其是可卡因和安非他明，可抑制多巴胺再摄取，导致清醒的高度警觉状态，然而发挥这一作用的多巴胺能神经元的位置尚不清楚。投射到前额叶皮层和腹侧纹状体的腹侧被盖区（VTA）多巴胺能神经元在行为觉醒期间的放电速率没有变化。此外，VTA病变不降低清醒度。我们假设腹侧导水管周围灰质（vPAG）中的多巴胺能细胞是长期寻找的群体。在目的1中，我们将通过标记自发性清醒或睡眠后的Fos和酪氨酸羟化酶来确定vPAG多巴胺能神经元是否具有清醒活性。在目标2和目标4中，我们将使用顺行和逆行示踪剂来定义vPAG - DA神经元与睡眠-觉醒控制系统的传入和传出连接。在目的3中，我们将通过体外切片贴片夹持技术研究多巴胺和多巴胺受体激动剂对vPAG多巴胺能投射神经元的影响。在目标5中，我们将选择性地用6-羟多巴胺损伤清醒活跃的多巴胺能神经元，并检查多巴胺再摄取抑制剂介导的基线睡眠-觉醒行为和唤醒状态。我们的初步结果表明，vPAG中的多巴胺能细胞是清醒活跃的，并且它们会影响基础呼吸。vPAG多巴胺能细胞病变导致总睡眠时间增加20%。vPAG多巴胺能细胞病变导致总睡眠时间增加20%。vPAG多巴胺能细胞；rriay提供了长期寻求的多巴胺唤醒影响，它们也可能在抑制多巴胺再摄取的精神兴奋剂的唤醒机制中发挥重要作用，并在帕金森病的睡眠障碍中发挥重要作用，帕金森病具有广泛的中脑边多巴胺能神经元损失。

DESCRIPTION (provided by applicant): A variety of drugs of abuse, including especially cocaine and amphetamine that inhibit dopamine reuptake, cause a wakeful hypervigilant state, however the location of the dopamlnergic neurons that play this role remains unclear. The ventral tegmental area (VTA) dopaminergic neurons that project to the prefrontal cortex and ventral striatum do not change in firing rate during behavioral wakefulness. In additon, lesion of the VTA does not decrease wakefulness. We hypothesize that the dopaminergic cells in the ventral periaqueductal gray matter (vPAG) are the long-sought group. In aim 1, we will determine whether vPAG dopaminergic neurons are wake-active by labeing Fos and tyrosine hydroxylase following spontaneous wakefulness or sleep. In aim 2 and 4, we will apply anterograde and retrograde tracers to define the afferent and efferent connections of the vPAG DA neurons with the sleep-wake control system. In aim 3, we will examine the effects of dopamine and dopamine receptor agonists on the vPAG dopaminergic projected neurons via patch-clamping technique on in vitro slice. In aim 5, we will selectively lesion the wake-active dopaminergic neurons by 6-hydroxydopamine and examine baseline sleep-wake behavior and arousal state mediated by dopamine reuptake inhibitor. Our preliminary results suggest that the dopaminergic cells in the vPAG are wake-active, and they project to basal f6rebraih,!,tlialamus, and prefrontal cortex, and reciprocally communicate with laterodorsal tegmental cholinergic cells, perifornical orexin/hypocretin cells, and locus coeruleus as well as the ventrolateral preoptic nucleus Lesion of vPAG dopaminergic cells causes 20% increase in total sleep. The vPAG dopaminergie cells;rriay provide the long sought dopamine waking influence, and they may also play importanfrqles in arousal mechanisms of psychostimulants that inhibit dopamine reuptake and in sleep disorders of'Parkinson's disease that has extensive loss of mesopontine dopaminergic neurons.