INSERM U1028, CNRS UMR5292, Neuroscience Research Center, University Lyon 1, Integrative Physiology of Brain Arousal System, Lyon, France.
Neuroscience. 2011 May 19;182:144-61. doi: 10.1016/j.neuroscience.2011.03.010. Epub 2011 Mar 22.
The median preoptic nucleus (MnPO), part of the anteroventral third ventricular region, plays a key role in body fluid homeostasis and cardiovascular regulation. Recently, a cluster of neurons showing sleep-related c-fos immunoreactivity was found in the rat MnPO, and a subsequent electrophysiological study found that nearly 76% of rat MnPO neurons exhibit increased discharge during sleep. In a recent single unit recording study in mice, we found that sleep-active neurons are not localized in any specific region of the preoptic/basal forebrain (POA/BFB). However, the discharge profiles of mouse MnPO neurons across wake-sleep states remained to be determined. In this study, we therefore examined whether the mouse MnPO contains a high proportion of sleep-active neurons and constitutes a distinct cluster of sleep-promoting neurons in the median preoptic region. We recorded a total of 234 single units in the MnPO, the laterally adjacent peri-MnPO, the dorsally adjacent medial septum (MS), and the ventrally adjacent periventricular (Pe)/medial preoptic (MPO) area (Pe/MPO). We found that the MnPO contained similar proportions of sleep-active (31.9%) and waking (W)-active (33.0%) neurons, together with many waking/paradoxical sleep (W/PS)-active neurons (23.4%), whereas the Pe/MPO and MS contained a high proportion of sleep-active neurons (66.0 and 62.9%, respectively), while the peri-MnPO contained a high proportion of W-active neurons (57.1%). In the MnPO, both W-active and W/PS-active neurons were distributed throughout the nucleus, whereas sleep-active neurons were mostly located on its border. Only slowly discharging (<5 Hz) slow-wave sleep (SWS)/PS-selective neurons were found in the MnPO. During the transition from W to SWS, all of these SWS/PS-selective neurons fired not before, but after, sleep onset, with a gradual increase in discharge rate. In addition to its well-known homeostatic and cardiovascular functions, the MnPO might modulate the sleep-waking cycle by playing different roles in sleep/wake state regulation.
中脑视前核（MnPO），前腹侧第三脑室区域的一部分，在体液稳态和心血管调节中起着关键作用。最近，在大鼠 MnPO 中发现了一群表现出睡眠相关 c-fos 免疫反应的神经元，随后的电生理研究发现，近 76%的大鼠 MnPO 神经元在睡眠期间放电增加。在最近的一项小鼠单细胞记录研究中，我们发现睡眠活跃神经元并非局限于视前/基底前脑（POA/BFB）的任何特定区域。然而，小鼠 MnPO 神经元在清醒-睡眠状态下的放电模式仍有待确定。在这项研究中，我们因此研究了小鼠 MnPO 是否包含高比例的睡眠活跃神经元，并构成了中脑视前区中一个独特的促眠神经元簇。我们在 MnPO 中总共记录了 234 个单细胞，在其外侧相邻peri-MnPO、背侧相邻内侧隔核（MS）和腹侧相邻室旁（Pe）/中脑视前（MPO）区（Pe/MPO）。我们发现，MnPO 中睡眠活跃（31.9%）和觉醒（W）活跃（33.0%）神经元的比例相似，同时还有许多觉醒/异相睡眠（W/PS）活跃神经元（23.4%），而 Pe/MPO 和 MS 中睡眠活跃神经元的比例较高（分别为 66.0%和 62.9%），而 peri-MnPO 中 W 活跃神经元的比例较高（57.1%）。在 MnPO 中，W 活跃和 W/PS 活跃神经元分布在整个核内，而睡眠活跃神经元主要位于其边界处。只有在 MnPO 中发现了放电频率较慢（<5 Hz）的慢波睡眠（SWS）/PS 选择性神经元。在从 W 向 SWS 的转变过程中，所有这些 SWS/PS 选择性神经元不是在睡眠开始之前，而是在睡眠开始之后才开始放电，放电率逐渐增加。除了其众所周知的稳态和心血管功能外，MnPO 可能通过在睡眠-觉醒周期调节中发挥不同的作用来调节睡眠-觉醒周期。
