SPASMOGENIC ACTIVITY OF THE AQUEOUS AND METHANOL EXTRACTS OF THE STEM BARK OF ANTHOCLEISTA VOGELII PLANCH. (LOGANIACEAE) IN RATS

Summary The effect of aqueous and methanol extracts of the stem bark of Anthocleista vogelii on the albinos rat smooth muscles was studied. The two extracts, produced a dose-dependent effect on the tone and force of the spontaneous contraction of the rat ileal and stomach smooth muscle fragments at concentrations ranging from 0.13 to 8.00 mg/ml. A concentration of 8.00 mg/ml on ileum and 4.00 mg/ml on stomach muscle produced maximal contractile effect in a single concentration. In cumulative concentrations, the aqueous extract produced a dosedependent contractile effect while the methanol extract produced a biphasic response. Atropine, administered 5 minutes before the contractile effect of the methanol extract at concentration of 0.1 µg/ml and 0.2 µg/ml completely inhibited the contractile effect of the methanol extract on both ileal and stomach smooth muscles. Similarly, the same concentrations of atropine reduced the contractile effect of acetylcholine by 55.01 and 100% on ileum and stomach fragments respectively.nifedipine (1.60 x 10 -1 µg/ml) and pyrilamine maleate (6.00 x 10 -1 µg/ml) completely abolished the spasmogenic effect of the methanol extract on both ileal and stomach smooth muscles fragments. These results point to a possible stimulation of these muscle fragments through muscarinic receptors which increase Ca 2+ mobilisation from both extra and intramuscular medium.