REGIONAL HEMODYNAMIC-EFFECTS OF THE BETA-ADRENOCEPTOR BLOCKERS TERTATOLOL AND PROPRANOLOL IN CONSCIOUS SPONTANEOUSLY HYPERTENSIVE RATS

  • 1 July 1986
    • journal article
    • research article
    • Vol. 282  (1) , 118-129
Abstract
The effects of the beta-adrenoceptor blocking drugs propranolol and tertatolol on regional hemodynamics were studied in conscious spontaneously hypertensive rats (SHR). Regional blood flows were measured using a 20 MHz directional pulsed Doppler system with miniaturized Doppler probes on the left renal artery, the superior mesenteric artery and the abdominal aorta. This allowed the determination of changes in resistances in the renal (RR), mesenteric (MR) and hindquarter (HQR) vascular beds. Tertatolol and propranolol caused an immediate fall in heart rate. Mean arterial pressure (MAP) increased during the first 15-30 min following injection of the beta-blockers. Thereafter it gradually fell below control values to reach significant decreases in MAP 3-4 hr following injection. Fifteen to thirty min after propranolol, vascular resistances increased in all 3 vascular beds significantly. Resistances returned to control values over the next 3-4 hr. Following tertatolol, HQR increased significantly during the first 15-30 min. MR and RR did not increase significantly whereas a significant fall in RR was observed after 3-4 hr. These data indicate different regional hemodynamic effects for tertatolol and propranolol in the conscious SHR. Tertatolol does not cause the renal and mesenteric vasoconstriction observed following propranolol.