Systemic and regional hemodynamic effects of propranolol in intact and anephric rats

We studied the changes in systemic and regional hemodynamics (using the radioactive microsphere technique) and catecholamine levels produced by propranolol in conscious semi-restrained intact or nephrectomized rats. Blood pressure increased by 17 +/- 2 and 32 +/- 2 mmHg in intact and anephric rats respectively, total peripheral vascular resistance by 61.5% and 176.5%, heart rate decreased by 23% and 35% respectively, cardiac index decreased by 35% and 57%, and stroke volume index by 14% and 30%. All changes were significantly more pronounced in anephric rats (p less than 0.05). Baseline norepinephrine, epinephrine, and dopamine were significantly higher in anephric versus intact animals and did not change significantly after B-blockade except for norepinephrine of the anephric rats which decreased. After B-blockade regional blood flows in most organs (including coronary flow) decreased in proportion to the diminished cardiac index except for brain flow which decreased by only 12% in intact and 25% in anephric animals. Local vascular resistances increased concomitantly and these changes were far more pronounced in the absence of kidneys. Thus, anephric state exacerbates all systemic and regional hemodynamic alterations caused by B-blockade in the rat.