WATER CLUSIA-COCLENSIS (CLUSIACEAE) LEAF EXTRACT EFFECT ON RAT BARORECEPTOR REFLEX RESPONSE

Here we analyse the effects of intravenous (i.v.) injection of an aque ous leaf extract of Clusia coclensis. It was injected through a cathet er implanted in the jugular vein at a speed of 30 ml/hr. with a dose o f 40 mg/kg, to six Sprague-Dawley (S.D.N.) rats (three males and three females) and a group of 6 hypertensive rats (S.H.R.), (three males an d three females). Blood pressure was measured directly with a catheter in the femoral arteria and the rate of heart beating with needle elec trodes. An hypotensive effect (p < 0.01) was recorded in both groups, it was the consequence of a blood pressure decrease of 63.4% in the no rmotensive rats and of 69.7% in the hypertensive rats. There was an st atistically significant change in heart beating rate in hypertensive r ats (13.61%) but not in normotensive rats (4.96%). A bilateral 1 min c arotid occlusion for 2 min prior and 2 min post administration of the extract produced an increase in blood pressure and in heart beating ra te. These parameters were not modified by the extract administration. After supression of the chronotropic mechanisms and baroreflex respons e, the cardiovascular effect of Clusia coclensis appears to be caused by a parasympathicomimetic effect, either through a decrease in contra ction strength or in the cardiac output. It could also be a direct eff ect on the smooth muscle of the peripheric blood vessels decreasing re sistance. Both mechanic;ms of action could explain this hypotensor eff ect.