Reis D J, Morrison S, Ruggiero D A
Division of Neurobiology, Cornell University Medical College, New York, New York 10021.
Hypertension. 1988 Feb;11(2 Pt 2):I8-13. doi: 10.1161/01.hyp.11.2_pt_2.i8.
Recent studies have demonstrated that the neurons of the lower brainstem that are responsible for maintaining normal levels of arterial pressure reside in a specific area of the rostral ventrolateral medulla. In rat, the critical zone corresponds to a small region containing a subpopulation of the adrenergic C1 group, defined immunocytochemically by the presence of the epinephrine-synthesizing enzyme phenylethanolamine N-methyltransferase. Neurons of this region (the C1 area), possibly including the adrenergic neurons, directly innervate preganglionic neurons in the spinal cord, and are tonically active and sympathoexcitatory. The excitatory transmitter released into the spinal cord is unknown. The discharge of C1 area neurons is locked to the cardiac cycle and, in turn, leads to firing of sympathetic preganglionic neurons. The C1 area neurons are inhibited by baroceptor input and mediate the vascular component of baroceptor reflexes. They also mediate somato-sympathetic pressor responses from skin and muscle and participate in reflex responses to hypoxia. The neurons are directly innervated by local neurons containing gamma-aminobutyric acid, acetylcholine, enkephalin, and substance P, all of which modulate arterial pressure. The C1 area is the site of the hypotensive actions of clonidine. Clonidine appears to act on imidazole receptors in the C1 area to lower arterial pressure. The natural ligand for these receptors may be a newly defined substance in brain, clonidine-displacing substance. Neurons of the C1 area appear to be the critical neuronal group governing the normal resting and reflex control of arterial pressure. They may play a critical role in the maintenance of elevated arterial pressure in hypertension and as a site of action of antihypertensive drugs.
最近的研究表明，负责维持动脉血压正常水平的脑桥下部神经元位于延髓头端腹外侧的一个特定区域。在大鼠中，关键区域对应于一个小区域，该区域包含肾上腺素能C1组的一个亚群，通过肾上腺素合成酶苯乙醇胺N-甲基转移酶的存在进行免疫细胞化学定义。该区域（C1区）的神经元，可能包括肾上腺素能神经元，直接支配脊髓中的节前神经元，并且具有紧张性活动且交感兴奋。释放到脊髓中的兴奋性递质尚不清楚。C1区神经元的放电与心动周期同步，进而导致交感节前神经元放电。C1区神经元受到压力感受器输入的抑制，并介导压力感受器反射的血管成分。它们还介导来自皮肤和肌肉的躯体-交感升压反应，并参与对缺氧的反射反应。这些神经元直接由含有γ-氨基丁酸、乙酰胆碱、脑啡肽和P物质的局部神经元支配，所有这些物质都调节动脉血压。C1区是可乐定降压作用的部位。可乐定似乎作用于C1区的咪唑受体以降低动脉血压。这些受体的天然配体可能是脑中一种新定义的物质，可乐定置换物质。C1区的神经元似乎是控制动脉血压正常静息和反射调节的关键神经元群。它们可能在高血压患者动脉血压升高的维持中起关键作用，并且是抗高血压药物的作用部位。
