Effect of Vitis vinifera Leaf Hydroalcoholic Extract on Rat Urinary Bladder Contractility

Several reports have shown the various medicinal effects of grape (Vitis vinifera) seed and skin extracts, such as antioxidant, hypotensive and vasodilatory effects. It has been recently shown the relaxatory effect of grape leaf hydroalcoholic extract on rat ileum, uterus, aorta, trachea and vas deferens as well as on frog isolated heart. The aim of the present study was to investigate the effect of Vitis vinifera leaf hydroalcoholic extract (VLHE) on contractility of urinary bladder smooth muscle in male rats and to study the mechanism(s) of its action.
The extract of dried grape leaf was prepared by macerated method using 70% ethanol for 72h in room temperature. The solvent was then evaporated. Urinary bladder was removed from male adult wistar rats after induction of deep anaesthetize by di-ethyle-ether. Tissues were then suspended in the organ bath containing physiologic solution (37oC, pH 7.4) bubbled with oxygen. Contractions were recorded isometrically under 1g resting tension.
VLHE at 1, 2, 4 and 8 mg/ml significantly reduced the urinary bladder contractions evoked by KCl (60 mM P The data suggest that VLHE induces spasmolytic effect in rat urinary bladder, possibly via blocking voltage dependent calcium channels and activation of calcium-activated potassium channels.