Effect of pinacidil on the contractile response of cyclophosphamide-treated rat vas deferens

Effect of pinacidil, a K+ channel opener, was studied on contractility of cyclophosphamide-treated rat vas deferens. The mean IC50 value of pinacidil against 1 mmol barium chloride induced rhythmic contractions and 40 mmol potassium chloride induced tonic contractions was significantly (P<0.01 and P<0.001, respectively) increased in the cyclophosphamide treated group as compared to the control. The mean EC50 value of norepinephrine (NE) in the presence of pinacidil (10(-6) mol) was significantly (P<0.001) increased in the cyclophosphamide treated group. These findings indicate that the responsiveness of rat vas deferens smooth muscle to pinacidil is reduced following cyclophosphamide treatment.