Single-point mutation in FAAH inhibits hydrolytic metabolism of NATs but not NAEs in vivo. (A) Schematic for generation of FAAH-S268D knockin mice. (B) Confirmation of FAAH-S268D mutation by Southern blotting, PCR, and genome sequencing. (C and D) NAEs (C) and NATs (D) in liver of FAAH-WT control, FAAH-S268D, and FAAH-KO mice (n = 3 or 4 per group). (C, Inset) C20:4 NAE (AEA). (E) NATs in plasma from FAAH-WT control and FAAH-S268D mice (n = 10 or 11 per group). (F) Plasma C18:1 NAT levels 30 min after injection of C18:1 NAT (n = 3). Data are presented as mean ± SEM. *P < 0.05 compared with control.