Phosphodiesterase enzymes Inhibitors prevents them from degrading cAMP and cGMP molecules in the cell, which is how phosphodiesterase inhibitors work. Nitric oxide, a molecule that controls the production of cAMP and cGMP, works to control physiological processes by lowering calcium concentrations in cells. Ultimately, phosphodiesterase enzymes degrade cAMP and cGMP.
Phosphodiesterase is unable to degrade cAMP and cGMP when it is inhibited. As a result, their concentrations inside the cell rise, which in turn causes calcium concentrations to drop. In the end, this causes smooth muscle relaxation and vasodilation in the target tissues.