CR4056 (6-(1H-imidazol-1-yl)-2-phenylquinazoline) is a selective inhibitor of MAO-A with IC50 of 202.7 nM and a ligand of I2-imidazoline receptor with IC50 of 596 nM.

The co-treatment of CR4056 (3-30 μM) with Bortezomib does not induce any significant difference in cell survival compared with BTZ-treated cells, either in H929 or in RPMI 8226 myeloma cells[1].

CR4056 (30 mg/kg) completely reverses the effect of capsaicin, increasing the paw withdrawal threshold (PWT) to 239. CR4056 obviously increases the mechanical withdrawal thresholds of both ipsilateral (F[4, 30]=19.97) and contralateral (F[4, 30]=31.58) hind paws. CR4056 dose-dependently reduces mechanical hyperalgesia with ED50 of 5.8 mg/kg. CR4056 dose-dependently decreases streptozotocin (STZ)-induced diabetic pain in rats (F[4, 35]=31.27). CR4056 (20 mg/kg; oral) increases endogenous norepinephrine (NE) levels by 68.2% in the parieto-occipital cortex. CR4056 (20 mg/kg; p.o.) obviously increases NE levels both in the cerebral cortex (63.1%) and in the lumbar spinal cord (51.3%). CR4056 (10 mg/kg) and Piroxicam (10 mg/kg) obviously reverse the decrease in the withdrawal threshold caused by Capsaicin[2].