Caffeine inhibits the central hypotensive action of propranolol in rats

ABSTRACT

Rats anaesthetized with alpha-chloralose were used to investigate the effects of caffeine on the central hypotensive action of d, l-propranolol(=propranolol). In these rats, intracisternal injections of graded doses (1.7 pmol to 13.6 pmol) of propranolol produced dose-dependent falls in mean arterial blood pressure (7 ñ 0.6 mm Hg to 27 ñ 2 mm Hg) which were inhibit by pretreatment with caffeine at a dose (12.9 pmol, intracisternally) that did not alter basal mean arterial blood pressure. The inhibition was reversible and it had an onset and duration of action of about 10 and 50 minutes respectively. It is concluded that caffeine may reduce the hypotensive response of propranolol during antihypertensive therapy with this drug (AU)