Definition Bypyridine derivative, isoenzyme fraction PDE III inhibitor. This inhibition decreases the hydrolysis of cAMP, leading to increased intracellular concentration of cAMP in the myocardium and vascular smooth muscle. Increased intracellular concentration of cAMP (little effect on cGMP) results in stimulation of protein kinases that phosphorylate substances responsible for uptake, storage, and release of Ca from sarcoplasmic reticulum during […]