TABLE 3

PDE enzyme function(s)

PDE Family Function(s)
PDE1 PDE1A probably serves to regulate vascular smooth muscle contraction and may play a role in sperm function; PDE1B is involved in dopaminergic signaling as well as immune cell activation and survival; PDE1C is required for vascular smooth muscle cell proliferation and may also regulate sperm function and neuronal signaling
PDE2 PDE2 frequently mediates cross-talk between cGMP and cAMP pathways; it regulates aldosterone secretion from the adrenal gland, cAMP and PKA phosphorylation of Ca+2 channels in the heart, cGMP in neurons, long-term memory, and barrier function of endothelial cells under inflammatory conditions
PDE3 PDE3A regulates cardiac contractility, platelet aggregation, vascular smooth muscle contraction, oocyte maturation, and regulation of renin release; PDE3B mediates insulin signaling, especially its antilipolytic effects; PDE3B also regulates cell cycle/proliferation and mediates the inhibitory effects of leptin and other signals on insulin secretion and renin release
PDE4 At least one form is expressed in most cells, and PDE4s play roles in a wide array of processes, including brain function, monocyte and macrophage activation, neutrophil infiltration, vascular smooth muscle proliferation, fertility, vasodilation, and cardiac contractility
PDE5 PDE5 is a well-documented regulator of vascular smooth muscle contraction, especially in penis and lung; it is involved in NO-cGMP signaling in platelets to control aggregation and may also play a role in regulation of cGMP signaling in the brain
PDE6 PDE6 is involved in signal transduction of the photoresponse in the eye; it may also regulate melatonin release from the pineal gland
PDE7 PDE7 is implicated to play a role in T-cell activation and activation of other inflammatory cells
PDE8 PDE8 may play a role in T cell activation, sperm, or leydig cell function
PDE9 The function of PDE9 is currently unknown, but it has been postulated to regulate NO-cGMP signaling in the brain
PDE10 PDE10A is thought to be a regulator of cGMP in the brain and may play a role in learning and memory
PDE11 PDE11 possibly has a role in sperm development and function