Table 1.

Different PDE families, their tissue and organ distribution and their main inhibitors, focusing on those mentioned in the main text.

PDE Type	Distribution	Inhibitors	Reference
PDE1	Heart, lungs, brain, smooth muscle.	Ibudilast, nimodipine, dioclein, IC86340, IC224, IC295.	[22,40]
PDE2	Heart, kidneys, brain, platelets, adrenal glands, lungs, liver, endothelial cells.	Ibudilast, oxindole, EHNA, ND7001, BAY-60–7750, PDP, IC933.	[22,40,45]
PDE3	Heart, kidneys, brain, lungs, smooth muscle, liver, platelets, adipocytes, immune cells.	Ibudilast, cilostazol, milrinone, cilostamide, siguazodan.	[22,40,56,58,59]
PDE4	Heart, kidneys, brain, platelets, Sertolli cells, liver, smooth muscle, lungs, endothelial cells, immune cells.	Ibudilast, rolipram, cilomast, roflumilast, NCS 613.	[22,40,45,55,57]
PDE5	Platelets, heart, lungs, smooth muscle, brain, endothelial cells.	Ibudilast, DMPPO, zaprinast, vardenafil, sildenafil, tadalafil	[40,45]
PDE6	Lungs, pineal gland, photoreceptors.	DMPPO, zaprinast, sildenafil, vardenafil.	[40]
PDE7	Heart, skeletal muscle, T lymphocytes, kidneys, brain, pancreas.	IC242, BRL 50481, ASB16165.	[40]
PDE8	Brain, eyes, testes, liver, heart, skeletal muscle, kidneys, thyroid, ovaries, T lymphocytes.	PF-04957325.	[40,42]
PDE9	Lungs, kidneys, liver, brain.	PF-04447943, BAY-73–6691	[40]
PDE10	Brain, testes, thyroid.	Ibudilast, MP-10, Papaverine, TP-10.	[20,40,66,67]
PDE11	Heart, liver, skeletal muscle, pituitary gland, prostate.	Ibudilast, non-selective.	[20,40]