Brown D L, Guyenet P G
Circ Res. 1985 Mar;56(3):359-69. doi: 10.1161/01.res.56.3.359.
In urethane-anesthetized rats, electrophysiological recordings of spontaneously active neurons in the vasopressor area of the rostral ventrolateral medulla were analyzed for participation in cardiovascular regulation. A total of 138 units were found which were inhibited by transient increases in mean arterial pressure elicited by intravenous injection of norepinephrine, aortic occlusion, or electrical stimulation of the hypothalamus, with 100% inhibition occurring at 148 mm Hg. Histograms of postsystolic activity showed that these units had pulse-synchronous rhythms which grew more prominent as arterial pressure increased. Furthermore, electrical stimulation of the superior laryngeal nerve, which elicited a vasodepressor response, strongly inhibited these units. Thus, these neurons were termed negatively correlated cardiovascular units. At least half of these cells project to or through the thoracic spinal cord. In addition, arterial pressure sensitivity is conveyed through carotid sinus and aortic arch afferents. Approximately half of the cardiovascular units are also excited by hypothalamic stimulation. Finally, analysis of neighboring cells showed that it is possible to distinguish between cardiovascular and respiratory units. These data are consistent with the concept of a medullary center which supports tonic sympathetic vasomotor tone and which mediates baroreceptor reflexes, as well as vascular responses of the defense reaction.
在氨基甲酸乙酯麻醉的大鼠中，分析了延髓头端腹外侧加压区自发活动神经元的电生理记录，以研究其在心血管调节中的作用。共发现138个单位，这些单位会被静脉注射去甲肾上腺素、主动脉阻断或下丘脑电刺激引起的平均动脉压短暂升高所抑制，在平均动脉压达到148毫米汞柱时抑制率达100%。收缩后活动的直方图显示，这些单位具有脉搏同步节律，且随着动脉压升高这种节律变得更加明显。此外，电刺激喉上神经会引发降压反应，同时强烈抑制这些单位。因此，这些神经元被称为负相关心血管单位。这些细胞中至少有一半投射到胸段脊髓或经胸段脊髓投射。此外，动脉压敏感性通过颈动脉窦和主动脉弓传入神经传导。大约一半的心血管单位也会被下丘脑刺激所兴奋。最后，对相邻细胞的分析表明，可以区分心血管单位和呼吸单位。这些数据与延髓中心的概念一致，该中心维持紧张性交感缩血管张力，介导压力感受器反射以及防御反应的血管反应。
