Phosphodiesterase type 3 (PDE3)

Phosphodiesterase type 3 (PDE3) is a family of enzymes, comprising the isoforms PDE3A and PDE3B, that regulates intracellular signaling by hydrolyzing the second messengers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) (1.1.3, 1.2.3). PDE3A is predominantly expressed in the myocardium, vascular smooth muscle, and platelets, where it modulates cardiac contractility, vascular tone, and platelet aggregation (1.2.1, 1.2.5). In contrast, PDE3B is primarily found in adipose tissue, liver, and pancreatic beta cells, playing a key role in the regulation of lipolysis and insulin signaling (1.2.3, 1.3.4). Pharmacological inhibition of PDE3 leads to elevated cAMP levels, resulting in positive inotropic effects in the heart and vasodilation in the peripheral vasculature, a combination often referred to as inodilation (1.3.1, 1.3.5). Consequently, PDE3 inhibitors like milrinone are utilized for the short-term management of acute decompensated heart failure, while cilostazol is used to treat intermittent claudication in peripheral arterial disease (1.1.2, 1.3.2). Despite their therapeutic benefits, the use of PDE3 inhibitors is constrained by significant safety concerns, including the risk of life-threatening ventricular arrhythmias and increased mortality observed with long-term administration in heart failure patients (1.3.1, 1.4.5).

Other names

cGMP-inhibited phosphodiesteraseCGI-PDEPhosphodiesterase 3Cyclic nucleotide phosphodiesterase type 3

Inhibition of PDE3 prevents the breakdown of cAMP and cGMP, leading to increased intracellular concentrations of these second messengers. In cardiomyocytes, elevated cAMP enhances calcium influx, increasing myocardial contractility (positive inotropy). In vascular smooth muscle, it promotes relaxation and vasodilation. In platelets, increased cAMP inhibits activation and aggregation.