URB597

338, 4

Adult male Wistar rats (250–300 g) and C57/BL6 or FAAH-/- mice

sterile 0.9% sodium chloride solution

URB597 binds in the hydrophobic pocket and catalytic core of FAAH that connects the active site residues to the membrane surface of FAAH. [1] URB597 inhibits FAAH activity in human liver microsomes with IC50 of 3 nM. [2] URB597 reduces the expression of the LPS-induced enzymes cyclo-oxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS, NOS2) in primary rat microglial cell, with a concomitant reduction in the release of the inflammatory mediators prostaglandin E2 (PGE2) and (NO) nitric oxide. [3] URB597 evokes Ca2+ entry in HEK293-F Cells transiently expressing human or rat TRPA1 gene. URB597 also activates Ca2+ entry in rat DRG neurons natively expressed TRPA1 channels. [4]

Pharmacology, Membrane fractions are prepared from brain homogenates, and FAAH activity is assayed using [3H]anandamide (anandamide[ethanolamine-3H], 60 Ci/mmol) as a substrate. Rat brain membranes (50 ug protein) are incubated for 30 min at 37 C in buffer containing [3H]anandamide and varying concentrations of URB597. At the end of the incubation period, we stopp the reactions with a mixture of chloroform/methanol and measured [3H]ethanolamine in the aqueous phase by liquid scintillation counting.

URB597 (KDS-4103) is a potent, orally bioavailable FAAH inhibitor with IC50 of 4.6 nM, with no activity on other cannabinoid-related targets. Phase 1.