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Effects of propranolol and tertatolol on cardiac output and regional blood flows in the rat
Author(s) -
Rochette L.,
Bralet J.,
Rochat C.
Publication year - 1987
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/ddr.430100104
Subject(s) - propranolol , medicine , anesthesia , heart rate , cardiac output , blood pressure , chemistry , hemodynamics
Tertatolol (±)‐1‐(tert‐butylamino)‐3(thiochroman‐8‐yloxy)‐2‐propanol, hydrochloride is a noncardioselective beta‐adrenoceptor antagonist that is devoid of partial agonist activity. The effects of this substance on regional blood flows (RBF) in the rat were studied in comparison with those of propranolol. Rats were artificially ventilated with a mixture of 70% nitrous oxide and 30% oxygen. RBFs were assessed using radioactive microspheres of 15 ± 5 μm diameter, injected into the left ventricle. An initial injection of microspheres ( 57 Co) was carried out 5 min before intravenous administration of propranolol (500 μg·kg −1 ), tertatolol (50 μg·kg −1 ) or physiological serum. A second microsphere administration ( 113 Tin) was performed 10 min after injection of the test substances. The animals were sacrificed 3 min after the second injection of microspheres. Neither modifications in arterial pH, pO 2 , pCO 2 , nor in the arterial blood pressure were observed with either propranolol or tertatolol. In contrast, a decrease in heart rate was observed (−22% with propranolol and −14% with tertatolol). The reduction in cardiac output was 33% with propranolol and 29% with tertatolol. Propranolol reduced blood flow to the majority of structures and organs examined; such a reduction was 39% in the cerebral hemispheres, 31% in the brainstems and of greater than 20% in all the renal zones studied. With tertatolol, no significant modifications of RBF were observed in any of the cortical or medullary renal zones investigated, nor in any of the cerebral areas studied; only in several colonic areas and in the skin of the abdomen and back, were reductions in RBF observed. These results demonstrate a difference in the effects of these two substances on renal and cerebral haemodynamics.