Soltis E E, Katovich M J
Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville 32610.
Clin Exp Hypertens A. 1991;13(1):117-32. doi: 10.3109/10641969109082618.
In an earlier report we observed alterations in aortic smooth muscle alpha- and beta-adrenergic responsiveness in the Dahl rat. The present study was designed to define the time course of these changes and further characterize the alterations in this model of hypertension. Four-week-old male Dahl salt-sensitive (DS) rats were placed on either a normal (DSN) or high salt diet (8% NaCl; DSH). Aortic smooth muscle responsiveness was studied at 3 and 6 weeks of the dietary treatment. No differences were seen between the 2 groups in either the contractile response to KCl or the relaxation responses to sodium nitrite and acetylcholine. Isoproterenol-induced relaxation was significantly attenuated and contractile response to norepinephrine (NE) were enhanced at 3 weeks of treatment in DSH rats, however, no differences were seen between the 2 groups at 6 weeks. Since alterations were seen only at 3 weeks of treatment, aortic smooth muscle responsiveness to the specific alpha-agonists phenylephrine (alpha 1), guanfacine (alpha 2) and contractile responses to NE in the presence of propranolol were evaluated at three weeks. No differences were observed between the 2 groups with any of these treatments. Thus, it appears that the increased NE responsiveness seen in aortic smooth muscle of DSH rats during the developmental stage of the hypertension is the result of a decrease in beta-adrenergic responsiveness and not an increase in alpha-adrenergic responsiveness.
在一份较早的报告中，我们观察到达尔大鼠主动脉平滑肌α和β肾上腺素能反应性的改变。本研究旨在确定这些变化的时间进程，并进一步描述该高血压模型中的改变特征。将四周龄雄性达尔盐敏感（DS）大鼠置于正常（DSN）或高盐饮食（8%氯化钠；DSH）环境中。在饮食治疗的第3周和第6周研究主动脉平滑肌反应性。两组在对氯化钾的收缩反应或对亚硝酸钠和乙酰胆碱的舒张反应方面均未观察到差异。在DSH大鼠中，治疗3周时异丙肾上腺素诱导的舒张显著减弱，对去甲肾上腺素（NE）的收缩反应增强，然而，在6周时两组之间未观察到差异。由于仅在治疗3周时观察到改变，因此在3周时评估了主动脉平滑肌对特异性α激动剂去氧肾上腺素（α1）、胍法辛（α2）的反应性以及在普萘洛尔存在下对NE的收缩反应。在这些治疗中的任何一种情况下，两组之间均未观察到差异。因此，似乎在高血压发展阶段DSH大鼠主动脉平滑肌中观察到的NE反应性增加是β肾上腺素能反应性降低的结果，而非α肾上腺素能反应性增加的结果。
