Benserazide is an inhibitor of dopa decarboxylase. It is often given with levodopa in the treatment of Parkinson's to prevent the conversion of levodopa to dopamine in the periphery, thereby increasing the amount that reaches the central nervous system an

PF-04449613 is a phosphodiesterase 9A (PDE9A) inhibitor (IC50= 22 nM).1It is selective for PDE9A over PDE1C (IC50= >1,000 nM), as well as over a variety of other PDEs, inhibiting PDE2-8, -10, and -11 activity by less than 30% in a panel of enzymes, ion channels, and transporters at 1 μM but does inhibit the human dopamine transporter (DAT; Ki= 293 nM). PF-04449613 (0.1-100 mg/kg, s.c.) increases cerebrospinal fluid (CSF) levels of cyclic GMP (cGMP) in rats. Subcutaneous administration of PF-04449613 (10 mg/kg) increases the rate of dendritic spine formation and elimination in mouse primary motor cortex pyramidal neuronsin vivo.2It increases the average running speed of mice in an accelerating rotarod task, indicating improved motor learning, at the same dose. 1.Claffey, M.M., Helal, C.J., Verhoest, P.R., et al.Application of structure-based drug design and parallel chemistry to identify selective, brain penetrant, in vivo active phosphodiesterase 9A inhibitorsJ. Med. Chem.55(21)9055-90

K134 is an inhibitor of phosphodiesterase 3. The IC50s of K134 for PDE3A, PDE3B, PDE5, PDE2 and PDE4 are 0.1, 0.28, 12.1, >300 and >300 μM, respectively.

Disodium monofluorophosphate (NSC248) 是丙酮酸激酶和碱性磷酸酶的竞争性抑制剂，它也不可逆地抑制磷酸化酶磷酸酶。

Endo CNTinh-03 具有抑制作用，可阻止 cAMP 和 cGMP 通过 G 蛋白偶联受体、腺苷酸环化酶及鸟苷酸环化酶的激动剂而升高（IC50为 4 μM）。此外，该化合物能够抑制霍乱毒素与Escherichia coli(STa) 毒素导致的氯离子电流，有效改善小鼠分泌性腹泻的症状，并在多囊肾病模型中防止囊肿的形成。

Yonkenafil HCl, a PDE5 inhibitor, is used potentially for the treatment of erectile dysfunction.