Dickerson L W, Panico W H, Kuhn F E, Willis A C, Fitzgerald J F, Meyer E L, Norman W P, Gillis R A
Department of Pharmacology, Georgetown University, Washington, District of Columbia 20007, USA.
Am J Physiol. 1997 Mar;272(3 Pt 2):R821-39. doi: 10.1152/ajpregu.1997.272.3.R821.
Studies were conducted in anesthetized, vagotomized dogs while blood pressure; blood flows in femoral, renal, mesenteric, and left circumflex coronary arteries; electrocardiogram; and regional cardiac contractile force were monitored. The ventral surface of the medulla was exposed, and pressor sites in the rostral ventrolateral medulla (RVLM) were mapped by microinjections of L-glutamate. L-Glutamate activation of the RVLM evoked selective effects on different components of the cardiovascular system. Increases of 20-130 mmHg in blood pressure were accompanied by vascular conductance decreases in the femoral (-48 +/- 4%), renal (-30 +/- 4%), and mesenteric (-38 +/- 3%) arterial beds. These effects were without any obvious topography within the RVLM. There were only small or negligible changes in heart rate (HR), cardiac contractile force, and coronary vascular conductance. Thus stimulation of the canine RVLM increased sympathetic tone selectively to structures other than the heart. Stimulation of the ventral medulla in a region that lay rostral to the RVLM and ventromedial to the facial nucleus selectively increased femoral vascular conductance by 103 +/- 33% and decreased vascular conductance in the renal (-20 +/- 5%) and mesenteric (-15 +/- 4%) arterial beds. There was no increase in HR, and the increases in blood pressure were relatively small. Immunohistochemical data led us, tentatively, to identify this rostral area as overlapping part of the A5 area.
在麻醉、切断迷走神经的犬类身上进行了研究，同时监测血压、股动脉、肾动脉、肠系膜动脉和左旋冠状动脉的血流量、心电图以及局部心脏收缩力。暴露延髓腹侧面，通过微量注射L-谷氨酸来绘制延髓头端腹外侧区（RVLM）的升压位点。RVLM的L-谷氨酸激活对心血管系统的不同组成部分产生了选择性影响。血压升高20 - 130 mmHg时，股动脉床（-48±4%）、肾动脉床（-30±4%）和肠系膜动脉床（-38±3%）的血管传导性降低。这些效应在RVLM内没有明显的局部定位。心率（HR）、心脏收缩力和冠状动脉传导性仅有微小或可忽略不计的变化。因此，刺激犬类的RVLM会选择性地增加除心脏以外结构的交感神经张力。刺激RVLM头侧且面神经核腹内侧的延髓腹侧区域，会使股动脉血管传导性选择性增加103±33%，并使肾动脉床（-20±5%）和肠系膜动脉床（-15±4%）的血管传导性降低。心率没有增加，血压升高幅度相对较小。免疫组织化学数据使我们初步确定这个头侧区域为A5区域的重叠部分。
