Hemodynamic Responses to Papaverine: Do Nitric Oxide, Cyclic GMP, or Calcium Mediate the Vasodilation?

Papaverine is a commonly used vasodilator of the internal mammary artery in cardiac surgery. The effects of papaverine with and without N(omega)-L-arginine methyl ester (L -NAME) (a nitric oxide production inhibitor) and/or zaprinast (a cyclic GMP inhibitor) or verapamil (calcium channel antagonist) on systemic vascular resistance in vivo have not been well documented. This study examines the hemodynamic responses to papaverine and attempts to identify the role of nitric oxide, cyclic guanosine monophosphate (GMP), and calcium in the vasodilation.