Effects of drugs on hypocretin and melanin concentrating hormone neurons

描述（由申请人提供）：2000年，我们的小组和Mignot的小组确定了人类发作性睡病伴卡他汀的原因是下丘脑泌素（Hcrt或食欲素）细胞的丢失。我们发现在发作性睡病伴cataerosis中Hcrt神经元损失90%。2007年，我们发现60%的Hcrt细胞损失与帕金森病的嗜睡有关。大多数研究的神经元系统与确定的递质的假设下，每组细胞的数量可以减少病理或年龄，但不能大幅增加。我们最近接收了一个“正常”人脑，其中含有114，000个Hcrt细胞，比平均数量高出50%，比我们在对照组中看到的最高数量高出37%。进一步调查显示，此人曾吸食海洛因。这表明，阿片类药物管理可能会永久增加Hcrt表达细胞的数量，这种改变可能与成瘾过程有关。在初步研究中，我们发现，吗啡给药增加了野生型小鼠的Hcrt细胞数量，就像它在人类成瘾者中所做的那样。我们建议确定吗啡给药后Hcrt细胞数量变化的幅度和时间过程，以及这种增加是永久性的程度。我们将观察吗啡对正常和发作性睡眠犬脑脊液中Hcrt水平的影响。我们将确定在Hcrt KO小鼠中施用吗啡对下丘脑“Hcrt细胞”（用Narp染色鉴定）的影响，以确定Hcrt是否是Hcrt基因表达所必需的。 吗啡后这些细胞的数量增加。我们将记录Hcrt细胞的单位活性， 自由活动的大鼠，以确定Hcrt细胞的生理反应，吗啡在幼稚和成瘾大鼠。我们将确定长期吗啡给药后小鼠Hcrt细胞群的增加是否与我们在未用药小鼠中报告的清醒任务中Fos表达模式相同。我们将在植入微透析探针用于诊断目的并给予吗啡缓解疼痛的人体中首次测量Hcrt-1、黑色素浓缩激素和吗啡给药后多巴胺的释放。我们将使用一种新开发的小鼠发作性睡病模型，DTA-食欲素小鼠，来确定增加Hcrt细胞数量的吗啡给药是否逆转发作性睡病的症状。该模型允许在成熟小鼠中选择性地、受控地缺失Hcrt细胞。我们有新的，令人兴奋的数据表明，一段时间的吗啡给药可以完全逆转这些小鼠的Hcrt细胞损失，这表明在人类发作性睡病中也应该有可能实现这种逆转。使用这个模型，我们也将确定是否吗啡条件性位置偏爱被逆转的Hcrt细胞的诱导变性。确定Hcrt细胞的特性可以被阿片类药物改变，将为人类嗜睡症的新治疗和可能的治愈奠定基础。它还将导致更好地了解阿片类药物依赖和抑郁症。神经递质表型可塑性的发现对临床和基础神经科学都具有重要意义。

DESCRIPTION (provided by applicant): In 2000, our group and Mignot's group identified the cause of human narcolepsy with cataplexy as a loss of hypocretin (Hcrt or orexin) cells. We found a 90% loss of Hcrt neurons in narcolepsy with cataplexy. In 2007, we identified a 60% Hcrt cell loss linked to the sleepiness of Parkinson's disease. Most studies of neuronal systems with identified transmitters have operated under the assumption that the number of cells in each group can be reduced with pathology or age, but cannot be substantially increased. We recently received a "normal" human brain that contained 114,000 Hcrt cells, 50% greater than the mean number and 37% greater than the highest number that we have seen in controls. Further investigation revealed that this individual was a former heroin addict. This suggested that opiate administration might permanently increase the number of Hcrt expressing cells, and that this alteration might be related to the addictive process. In pilot studies, we found that morphine administration increased the number of Hcrt cells in wild type mice, as it apparently had in the human addict. We propose to determine the magnitude and time course of the change in Hcrt cell number with morphine administration, and the extent to which this increase is permanent. We will observe the effect of morphine on Hcrt levels in the cerebrospinal fluid of normal and narcoleptic dogs. We will determine the effect of morphine administration in Hcrt KO mice on hypothalamic "Hcrt cells" (identified with Narp staining) to determine if Hcrt is necessary for the increase in the number of these cells after morphine. We will record unit activity of Hcrt cells in freely moving rats to determine the physiological response of Hcrt cells to morphine in naive and addicted rats. We will determine if the increased Hcrt cell population in mice after long-term morphine administration shows the same pattern of Fos expression in waking tasks as we have reported in drug naive mice. We will make the first measurements of Hcrt-1, melanin concentrating hormone, and dopamine release after morphine administration in humans who have been implanted with microdialysis probes for diagnostic purposes and given morphine for pain relief. We will determine if morphine administration that increases the number of Hcrt cells, reverses the symptoms of narcolepsy, using a newly developed mouse narcolepsy model, the DTA-orexin mouse. This model allows selective, controlled deletion of Hcrt cells in mature mice. We have new, exciting data showing that a period of morphine administration can completely reverse Hcrt cell loss in these mice, indicating that it should also be possible to achieve this reversal in human narcoleptics. Using this model, we will also determine if morphine conditioned place preference is reversed by induced degeneration of Hcrt cells. Establishing that the properties of Hcrt cells can be altered by opiates, will lay the foundation for a new treatment, and a possible cure, for human narcolepsy. It will also lead to a better understanding of opiate dependence and depression. The discovery of plasticity of neuronal transmitter phenotype has important implications for both clinical and basic neuroscience.