Phosphodiesterase III (PDE3)

Phosphodiesterase III (PDE3) is a member of the phosphodiesterase enzyme family that hydrolyzes cyclic nucleotides such as cAMP and cGMP, playing a critical role in cellular signaling. It regulates cardiac muscle contractility, vascular smooth muscle tone, and platelet aggregation. There are two main genes encoding PDE3 isoforms: PDE3A and PDE3B. PDE3 inhibitors are used for acute heart failure management, peripheral arterial disease, and prevention/treatment of thrombocytosis-related conditions, but long-term use is associated with increased risk of arrhythmias and mortality.

Blockade of PDE3 leads to increased cellular concentrations of cAMP/cGMP, resulting in enhanced cardiac contractility, faster myocardial relaxation, vasodilation, and reduced platelet aggregation through PKA activation.