BIBP 3226 trifluoroacetate is a mixed non-peptide neuropeptide Y Y1(NPY Y1) and neuropeptide FF (NPFF) receptor antagonist (Kivalues are 1.1, 79, 108, > 1000, > 1000 and >1000 for rNPY Y1, hNPFF2, rNPFF, rNPY Y2, rNPY Y4and rNPY Y5respectively). Produces an anxiogenic-like effect in rats following i.c.v. administration.