Median Preoptic Nucleus and the Control of Sleep

损毁、刺激和神经元记录实验结果支持下丘脑视前区(POA)在睡眠控制中的作用。推测睡眠调节细胞群在POA内的确切位置尚不完全清楚，但通过应用c-fos蛋白免疫反应性(IR)方法已取得最新进展。在大鼠的腹外侧部POA(VlPOA)中有一组局部神经元在睡眠时表现出Fos-IR。研究表明，vlPOA神经元投射到下丘脑后部和脑干的单胺能觉醒系统，并含有抑制性神经递质γ-氨基丁酸(GABA)。神经元记录研究证实，在vlPOA内存在与睡眠相关的放电模式的神经元。拟议工作的目标是描述第二个POA区域的解剖学和生理学特征，在该区域，显示SEEP相关Fos-IR的神经元已被定位，即正中视前核(MnPN)。拟议的实验将回答以下问题：1)MnPN是否像以前在vlPOA中发现的那样，含有高度集中的具有睡眠相关放电模式的神经元？2)表现出睡眠相关Fos-IR的MnPN神经元也是GABA能的吗？3)表现出睡眠相关Fos-IR的MnPN神经元是否投射到大细胞基底前脑、下丘脑外侧穹隆周围区、中缝背核和背外侧脑桥的觉醒系统？4)具有睡眠相关放电的MnPN神经元的一个子集也是温度敏感的，正如先前对vlPOA神经元所显示的那样？5)参与体液平衡控制的MnPN神经元是否与睡眠相关的MnPN神经元是一个独立的群体？拟议的工作将深入研究一个重要的POA神经元组，MnPN的解剖，神经化学和电生理特征。计划中的实验将有助于更全面地了解下丘脑机制在正常和紊乱的睡眠和唤醒状态中的作用。

A role for the preoptic area (POA) of the hypothalamus in the control of sleep is supported by the results of lesion, stimulation and neuronal recording experiments. The precise location of putative sleep-regulatory cell groups within the POA is incompletely understood, but recent progress has been made through application of the c-fos protein immunoreactivity (IR) method. A localized group of neurons in the ventrolateral POA (vlPOA) that exhibit Fos-IR during sleep has been described in rat. vlPOA neurons have been shown to project to monoaminergic arousal systems in the posterior hypothalamus and brainstem and to contain the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Neuronal recording studies confirmed the presence of neurons with sleep-related discharge patterns within the vlPOA. The goal of proposed work is to characterize the anatomy and physiology of a second POA region where neurons exhibiting seep- related Fos-IR have been localized, the median preoptic nucleus (MnPN). Proposed experiments will answer the following questions: 1) Does the MnPN contain a high concentration of neurons with sleep-related discharge patterns, like that previously found in the vlPOA? 2) Are MnPN neurons that exhibit sleep-related Fos-IR also GABAergic? 3) Do MnPN neurons that exhibit sleep-related Fos-IR project to arousal systems in the magnocellular basal forebrain, the perifornical region of the lateral hypothalamus, the dorsal raphe nucleus and the dorsolateral pons? 4) Are a subset of MnPN neurons with sleep- related discharge also thermosensitive, as has been previously shown for vlPOA neurons? 5) Are MnPN neurons that are involved in the control of body fluid homeostasis a separate population from sleep-related MnPN neurons? Proposed work will examine in depth the anatomical, neurochemical, and electrophysiological features of an important POA neuronal group, the MnPN. Planned experiments will contribute to a more complete understanding of the role of hypothalamic mechanisms in normal and disordered sleep and arousal states.