In Vitro
BI-409306 is a potent and selective PDE9A inhibitor, with an IC50 of 52 nM, and shows weak activity against other PDEs, such as PDE1A (IC50, 1.4 µM), PDE1C (IC50, 1.0 µM), PDE2A, PDE3A, PDE4B, PDE5A, PDE6AB, PDE7A, and PDE10A (IC50 all > 10 μM), and has no obvious effect on 95 non-PDE targets at 10 µM. BI-409306 enhances long-term potentiation (LTP) in rat hippocampal slices