Anxiogenic-like effect of the neuropeptide Y Y-1 receptor antagonist BIBP3226: Antagonism with diazepam

The effect of the novel non-peptide neuropeptide Y Y-1 receptor antagonist BIBP3226, N-2-(diphenylacetyl)-N-[(4-hydroxyphenyl)methyl]-D-arginine amide, on exploratory behaviour of rats in the elevated plus-maze was studied. BIBP3226 (0.5 and 5 mu g, i.c.v.) induced an anxiogenic-like effect at the higher dose tested. This effect was antagonised by diazepam (0.5 mg/kg). The anxiogenic-like effect of BIBP3226 was not related to a decrease in general locomotor activity. These findings support the hypothesis that neuropeptide Y Y-1 receptor subtype is involved in anxiety regulation.