Table 1 Basic characteristics of PDE3, PDE4, PDE5, and their selective chemical inhibitors.

PDE3A

0.02–0.15

0.18

Heart; vascular smooth muscle; platelets; oocyte; kidney

Milrinone

150 nmol/L

^{3, 18, 254, 255, 256}

PDE3B

0.28

0.38

Vascular smooth muscle; adipocytes; hepatocytes; kidney; β cells; developing sperm; T lymphocytes; macrophages

Amrinone

16.7 μmol/L

Enoximone

1.8 μmol/L

Pimobendan

2.4 μmol/L

Cilastazol

200 nmol/L

PDE4A

–

2.9–10

Ubiquitous

Rolipram

1 μmol/L

^{3, 18}

PDE4B

–

1.5–4.7

Ubiquitous

Ro 20-1724

2 μmol/L

PDE4C

–

1.7

Lung; testis; neuronal cells

Cilomilast

120 nmol/L

PDE4D

–

1.2–5.9

Ubiquitous

Roflumilast

0.8 nmol/L

PDE5A

2.9–6.2

290

Platelets; vascular smooth muscle; brain; lung; heart; kidney; skeletal muscle

Sildenafil

4 nmol/L

^{3, 18}

Vardenafil

0.1 nmol/L

Tadalafil

2 nmol/L

Udenafil

6 nmol/L