Fig. 1.
Effect of α1, β1,2-adrenergic blockade on blood pressure in young and old female spontaneously hypertensive rats (SHR). A: mean arterial pressure (MAP). MAP was measured during a 4-day baseline period and during infusion of terazosin and propranolol (10 mg·kg−1·day−1 sc each drug) in young (aged 4 mos, n = 6) and old (aged 18–20 mo, n = 6) female SHR. After infusion, rats were allowed to recover over the next 7 days, and MAP measurements were continued. Data are shown as MAP ± SE. *P < 0.05, compared with young females; §P < 0.05 compared with baseline MAP in same aged animals. B: percentage change in blood pressure comparison for day 8 vs. day 4 in old vs. young female SHR. Data are shown as percentage for either young or old females. *P < 0.05, old vs. young females.