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)9055-9068(2012) 2.Lai, B., Li, M., Hu, A., et al.The phosphodiesterase 9 inhibitor PF-04449613 promotes dendritic spine formation and performance improvement after motor learningDev. Neurobiol.78(9)859-872(2018)
IMR687 is a PDE9 inhibitor that slows or stops the hydrolysis of cGMP. IMR687 can be regarded as a highly promising drug against Alzheimer's for improving memory.
Irsenontrine (E2027) maleate is a selective and orally active inhibitor of phosphodiesterase 9 (PDE9). It can be utilized in the study of neurological diseases.