Yang T L, Chai C Y, Yen C T
Department of Zoology, National Taiwan University, Taipei, Republic of China.
Am J Physiol. 1995 Apr;268(4 Pt 2):H1499-509. doi: 10.1152/ajpheart.1995.268.4.H1499.
The distribution and reactivity of vasomotor sites in the ventrolateral (VLM) and dorsomedial medulla (DMM) of stroke-prone spontaneously hypertensive rats (SHRSP), spontaneously hypertensive rats (SHR), and Wistar-Kyoto rats (WKY) were compared. Rats were anesthetized with alpha-chloralose and urethan. Baroreceptor denervation and vagotomy were performed. L-Glutamate (Glu, 10 mM, 30 nl) was microinjected into the DMM or VLM to identify vasoactive sites. The extent and the patterns of distribution of these sites in the three strains of rats were similar. The dose-response curve of the vasoactive site was studied with 1-500 pmol of Glu. The maximum responses of blood pressure and renal sympathetic activity were larger and threshold doses of Glu were lower in hypertensive rats. The significance of the differences among the strains was analyzed before and after adjustment for baseline pressure or activity. Most of the differences were statistically significant before baseline adjustment. After baseline adjustment, many differences between the SHRSP and the WKY remained significant. However, the only significant difference detected between the SHR and the WKY was the threshold dose for eliciting renal sympathetic change in the caudal VLM. These results suggest that there may be a general increase in excitability of the vasomotor neurons in the medulla of the hypertensive rats.
比较了易患中风的自发性高血压大鼠（SHRSP）、自发性高血压大鼠（SHR）和Wistar-Kyoto大鼠（WKY）延髓腹外侧（VLM）和背内侧（DMM）血管运动位点的分布和反应性。大鼠用α-氯醛糖和乌拉坦麻醉。进行了压力感受器去神经支配和迷走神经切断术。将L-谷氨酸（Glu，10 mM，30 nl）微量注射到DMM或VLM中以识别血管活性位点。这三个大鼠品系中这些位点的分布范围和模式相似。用1 - 500 pmol的Glu研究血管活性位点的剂量 - 反应曲线。高血压大鼠的血压和肾交感神经活动的最大反应更大，Glu的阈值剂量更低。在对基线压力或活动进行调整之前和之后分析了品系间差异的显著性。在基线调整之前，大多数差异具有统计学意义。在基线调整之后，SHRSP和WKY之间的许多差异仍然显著。然而，SHR和WKY之间唯一检测到的显著差异是在尾侧VLM中引发肾交感神经变化的阈值剂量。这些结果表明，高血压大鼠延髓中血管运动神经元的兴奋性可能普遍增加。
