Extracellular Calcium and Induction of Uterine Muscle Contraction by Aqueous Ethanolic Leaf Extract of Mucuna pruriens

Calcium (Ca^2+) serves as an essential signaling molecule in biological systems, regulating a wide range of cellular processes of which uterine smooth muscle contraction is among. The present study was designed to evaluate the involvement of Ca^2+ on isolated uterine muscle contraction induced by aqueous ethanolic leaf extract of Mucuna pruriens (M. pruriens). Uterine muscle contraction induced by the extract was concentration-dependent and was completely abolished (100%; P 0.05) in nominally Ca^2+ -free physiological salt solution and in solutions containing (EGTA 1.5 mmol), lanthanium chloride (1.5 and 3 mmol), caffeine (3and 4.4 mmol) and verapamil (0.007- 0.14 μmol). It is concluded that the inability of the extract to produce contractions in Ca^2+ -free media, indicates that it lacks the ability to mobilize calcium from intracellular storage sites. Hence, its uterine stimulatory property is therefore solely dependent on extracellular Ca^2+.