EFFECTS OF AQUEOUS EXTRACT OF BAPHIA-NITIDA ON ISOLATED CARDIAC TISSUES

The pharmacological action of cold aqueous extract of fresh leaves of Baphia nitida was studied on cardiac preparations. The extract (5.0 X 10(-3) g mL) reduced the rate and force of contraction of the isolated rabbit heart. The rate and force of contraction of the spontaneously beating rat atria was dose-dependently reduced by 5.0 x 10(-4) to 2.5 x 10(-2) g/mL of the extract and this effect was not antagonized by 3.45 X 10(-7) M atropine. The extract (5.0 X 10(-2) g mL) completely blocked the positive chronotropic and inotropic effects of 10 mm CaCl2 but only reduced that of 1.61 X 10(-7)M isoprenaline. The effect of the extract on CaCl2-induced responses of the rat atria was not affected by 3 x 10(-7) m propranolol. The use of this extract for treating palpitation locally may be related to its negative chronotropic and inotropic effects.