The pharmacological effects of Musanga cecropioides
on rat thoracic aorta were examined in high K+
medium (55mM), Ca2+
3mM) induced vasoconstriction was inhibited by Musanga cecropioides
in a concentration-dependent manner. The tonic contractions elicited by KCI 55mM were relaxed by Musanga and were more marked in 0.45mM Ca2+
than 1.8mM Ca2+
medium. NA -induced responses were antagonized non competitively by Musanga. NA- sustained contraction was relaxed, the relaxing effect of Musanga was not antagonized by indomethacin or methylene blue. It is concluded that Musanga relaxation of the rat aorta does not involve cyclo-oxygenase, nor cAMP pathway, but unique, unlike those of known classical vasodilators.