Conway J, Hatton R, Keddie J, Dawes P
Hypertension. 1979 Jul-Aug;1(4):402-9. doi: 10.1161/01.hyp.1.4.402.
Sodium depletion was induced in dogs to raise plasma renin activity (PRA) from 1.11 to 26.48 ng/ml/hr. Little overall change in blood pressure (BP) occurred, but cardiac output (CO) and central venous pressure fell, while total peripheral resistance and heart rate (HR) increased. A nonapeptide converting enzyme inhibitor (CEI) produced a fall in BP which was linearly related to log. PRA; the intercept with PRA was at 1.05 ng/ml/hr, close to the average value for dogs on a normal diet. The fall in BP with this agent was not accompanied by an increase in HR or CO. When Sar1-Ala8 angiotensin II was used to antagonize the action of angiotensin, the fall in BP was also linearly related to log. PRA. However, for a given level of PRA this fall in BP was less than that achieved with CEI and the intercept of BP fall with PRA was 2.6 ng/ml/hr. Again with this agent there was little change in HR or CO as BP was reduced. Thus, both antagonists lowered peripheral resistance without exciting the homeostatic reflexes indicating that, as PRA rose above the normal resting level, the angiotensin generated had both a direct and indirect effect in maintaining BP.
通过使狗出现钠缺失，将血浆肾素活性（PRA）从1.11 ng/ml/小时提高到26.48 ng/ml/小时。血压（BP）总体变化不大，但心输出量（CO）和中心静脉压下降，而总外周阻力和心率（HR）增加。一种九肽转换酶抑制剂（CEI）使血压下降，且与log.PRA呈线性相关；与PRA的截距为1.05 ng/ml/小时，接近正常饮食狗的平均值。使用该药物导致的血压下降并未伴随心率或心输出量增加。当使用Sar1 - Ala8血管紧张素II拮抗血管紧张素的作用时，血压下降也与log.PRA呈线性相关。然而，对于给定的PRA水平，这种血压下降幅度小于使用CEI时的降幅，且血压下降与PRA的截距为2.6 ng/ml/小时。同样，使用该药物时，随着血压降低，心率或心输出量变化不大。因此，两种拮抗剂均降低了外周阻力，且未激发稳态反射，这表明，当PRA升高至正常静息水平以上时，生成的血管紧张素在维持血压方面具有直接和间接作用。
