Hirasawa M, Nishihara M, Takahashi M
Department of Veterinary Physiology, Veterinary Medical Science, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113, Japan.
Brain Res. 1998 Jun 22;797(1):103-8. doi: 10.1016/s0006-8993(98)00339-4.
Cardiovascular change is one of the common features of paradoxical sleep. Our study offers evidence that one of the central areas regulating the circulation during sleep is the ventromedial nucleus of the hypothalamus (VMH). We found a group of neurons in this hypothalamic nucleus of rats whose electrical activity was exclusively increased during paradoxical sleep, and was associated with a reduction in heart rate. The onset of this neural activity usually followed that of paradoxical sleep. The incidence and duration of paradoxical sleep was increased by means of microinjection of carbachol, a cholinergic agonist, into the pontine reticular formation, and the neural activity of the VMH still appeared in synchrony with carbachol-induced paradoxical sleep. These results suggest that the cholinergic paradoxical sleep-inducing mechanism in the pons facilitate the excitability of these neurons. We have previously shown that these VMH neurons suppress blood pressure and heart rate via inhibition of the vasomotor neurons in the medulla oblongata. Taken together, our findings suggest that a group of neurons in the VMH suppresses the circulatory system during paradoxical sleep.
心血管变化是异相睡眠的常见特征之一。我们的研究提供了证据，表明睡眠期间调节循环的中枢区域之一是下丘脑腹内侧核（VMH）。我们在大鼠的这个下丘脑核中发现了一组神经元，其电活动仅在异相睡眠期间增加，并与心率降低有关。这种神经活动的开始通常跟随异相睡眠的开始。通过向脑桥网状结构微量注射胆碱能激动剂卡巴胆碱，异相睡眠的发生率和持续时间增加，并且VMH的神经活动仍然与卡巴胆碱诱导的异相睡眠同步出现。这些结果表明，脑桥中胆碱能诱导异相睡眠的机制促进了这些神经元的兴奋性。我们之前已经表明，这些VMH神经元通过抑制延髓中的血管运动神经元来抑制血压和心率。综上所述，我们的研究结果表明，VMH中的一组神经元在异相睡眠期间抑制循环系统。
