Mehta Rachna, Khanday Mudasir Ahmad, Mallick Birendra Nath
School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Neurosci Lett. 2015 Mar 17;590:62-7. doi: 10.1016/j.neulet.2015.01.067. Epub 2015 Jan 28.
Rapid eye movement sleep (REMS) serves house-keeping function of the brain and its loss affects several pathophysiological processes. Relative levels of neurotransmitters including orexin A (Orx-A) in various parts of the brain in health and diseases are among the key factors for modulation of behaviors, including REMS. The level of neurotransmitter in an area in the brain directly depends on number of projecting neurons and their firing rates. The locus coeruleus (LC), the site of REM-OFF neurons, receives densest, while the pedunculo-pontine area (PPT), the site of REM-ON neurons receives lesser projections from the Orx-ergic neurons. Further, the Orx-ergic neurons are active during waking and silent during REMS and NREMS. Therefore, the level of Orx-A in discrete regions of the brain is likely to be different during normal and altered states, which in turn is likely to be responsible for altered behaviors in health and diseases, including in relation to REMS. Therefore, in the present study, we estimated Orx-A level in LC, cortex, posterior hypothalamus (PH), hippocampus, and PPT after 96 h REMSD, in post-deprivation recovered rats and in control rats. This is the first report of estimation of Orx-A in different brain regions after prolonged REMSD. It was observed that after REMSD the Orx-A level increased significantly in LC, cortex and PH which returned to normal level after recovery; however, the level did not change in the hippocampus and PPT. The Orx-A induced modulation of REMS could be secondary to increased waking.
快速眼动睡眠（REMS）对大脑起到清理功能，其缺失会影响多种病理生理过程。包括食欲素A（Orx-A）在内的神经递质在健康和疾病状态下大脑不同部位的相对水平，是调节包括快速眼动睡眠在内的行为的关键因素之一。大脑某一区域的神经递质水平直接取决于投射神经元的数量及其放电频率。蓝斑核（LC）是快速眼动睡眠关闭神经元的所在部位，接受最密集的投射，而脑桥脚被盖区（PPT）是快速眼动睡眠开启神经元的所在部位，接受来自食欲素能神经元较少的投射。此外，食欲素能神经元在清醒时活跃，在快速眼动睡眠和非快速眼动睡眠时沉默。因此，大脑不同区域的食欲素A水平在正常和改变状态下可能不同，这反过来可能导致健康和疾病状态下行为的改变，包括与快速眼动睡眠相关的改变。因此，在本研究中，我们估计了96小时快速眼动睡眠剥夺后、剥夺后恢复的大鼠以及对照大鼠的蓝斑核、皮质、下丘脑后部（PH）、海马体和脑桥脚被盖区中的食欲素A水平。这是关于长时间快速眼动睡眠剥夺后不同脑区食欲素A水平估计的首次报告。观察到快速眼动睡眠剥夺后，蓝斑核、皮质和下丘脑后部的食欲素A水平显著升高，恢复后恢复到正常水平；然而海马体和脑桥脚被盖区的水平没有变化。食欲素A对快速眼动睡眠的调节可能继发于清醒状态的增加。
