The effect of labetalol and propranolol on the development of hypertension in spontaneously hypertensive rats
Gumułka, W.S.; Zalewska-Rutczyńska, Z.
Acta Physiologica Polonica 35(1): 41-46
1984
ISSN/ISBN: 0044-6033 PMID: 6534080 Document Number: 236650
The effect of long-term administration of propranolol (0.2 and 0.4 mg/kg-1 p.o. (30 mm Hg). After drug withdrawal a rapid rise was observed in the arterial pressure to values approaching the values recorded in control animals. In the animals receiving labetalol parenterally (1 mg/kg-1 i.p.) the blood pressure was significantly lower than in control rats. After drug withdrawal the blood pressure increased gradually; however, even on the 54th day of the experiment it was slightly below that in controls. Propranolol given orally in doses of 0.2 mg/kg-1 delayed the development of hypertension, while in the dose of 0.4 mg/kg-1 it prevented its development. After withdrawal of the lower drug dose the blood pressure remained for .apprx. 2 wk at a level similar to the previous one, later on it increased steeply to the values observed in controls. These investigations confirm the hypotension action of labetalol, but in the prevention of hypertension development this drug is not as effective as propranolol.