Denbufylline (BRL 30892) 是一种磷酸二酯酶-4 (PDE4) 抑制剂，通过抑制细胞内 cAMP (环磷酸腺苷) 的降解来升高细胞内 cAMP 水平，从而调节多种细胞功能。Denbufylline 可用于慢性阻塞性肺病 (COPD)、哮喘及其他炎症性疾病的研究。

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

Mitapivat (PKR-IN-1) 是口服具有活性的变构丙酮酸激酶 (pyruvate kinase) 激活剂，其AC50=20 nM。它在广泛的 PKLR 基因型中增加酶活性、蛋白质稳定性和 ATP 水平。它有潜在的恢复 PK 缺乏的糖酵解途径活性的作用。

Sp-cAMPS triethylamine，一种 cAMP 类似物，是一种依赖 cAMP 的PKAI 和PKAII 的有效激活剂。Sp-cAMPS triethylamine 还是一种有效的竞争性磷酸二酯酶 (PDE3A) 抑制剂，Ki 为 47.6 µM。Sp-cAMPS triethylamine 以EC50为 40 μM 来结合PDE10GAF 域。

PF-8380 hydrochloride 是一种有效的autotaxin 抑制剂，体外酶实验和人类全血细胞实验中，IC50分别为 2.8 nM 和 101 nM。

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