The effects of the Chinese herb
Wu-Chu-Yu (Evodiae fructus) on the cardiovascular function were assessed in anesthetized cats, conscious rats, and isolated preparations of rat aortic strip and auricle. In anesthetized cats,
intravenous administration of alcohol-water
crude extracts of
Wu-Chu-Yu (0.03-0.24 g/kg) produced a dose-dependent
hypertension and an increased contractile force of nictitating membrane which lasted for more than 5 min in higher doses.
Phentolamine, but not
tetraethylammonium antagonized
hypertension and the increased contractile force of nictitating membrane induced by
Wu-Chu-Yu. In conscious rats,
hypertension was also observed by intraperitoneal administration of
Wu-Chu-Yu (6 g/kg). Bilateral
nephrectomy, administration of
phentolamine or
propranolol, all significantly decreased the hypertensive effect of
Wu-Chu-Yu. Pretreatment with
reserpine 24 hours in advance did not change the pressor effect of the
crude extract. In aortic strip preparations,
Wu-Chu-Yu caused the increase of contractile force, and the dose-response curve was parallel shift to the right in the presence of
phentolamine. In auricle preparations,
Wu-Chu-Yu produced positive inotropic and positive chronotropic effects, and the presence of
propranolol changed the slope of
Wu-Chu-Yu's dose-inotropic effect curve and reversed the chronotropic effect from positive to negative. Both in vivo and in vitro results suggested that alpha and beta
adrenoceptors were directly involved in the cardiovascular effects of
Wu-Chu-Yu.