Mechanism of Dopaminergic Arousal

描述(申请人提供)：各种滥用药物，特别是可卡因和苯丙胺，抑制多巴胺的再摄取，导致清醒的高度警惕状态，然而，发挥这一作用的多巴胺能神经元的位置仍然不清楚。投射到前额叶皮质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过程中不改变放电率。此外，损毁VTA不会降低觉醒能力。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组。在目标1中，我们将确定VPAG多巴胺能神经元是否在自发觉醒或睡眠后通过释放Fos和酪氨酸羟基酶来激活。在目标2和4中，我们将应用顺行和逆行示踪剂来确定VPAG DA神经元与睡眠-觉醒控制系统的传入和传出联系。在目的3中，我们将通过体外脑片膜片钳技术检测多巴胺及其受体激动剂对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-羟基多巴胺损毁觉醒活性的多巴胺能神经元，并检测由多巴胺再摄取抑制剂介导的基线睡眠-觉醒行为和觉醒状态。我们的初步结果表明，VPAG内的多巴胺能细胞是觉醒活跃的，它们投射到基底f6脑区、延髓和前额叶皮质，并与背侧被盖胆碱能细胞、穹隆周围食欲素/下克隆体细胞、蓝斑以及VPAG多巴胺能细胞的腹外侧视前核损伤相互联系，使总睡眠增加20%。VPAG多巴胺细胞可能提供长期寻求的多巴胺觉醒影响，它们也可能在抑制多巴胺再摄取的精神刺激剂的唤醒机制中发挥重要作用，以及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多巴胺能神经元丢失。

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.