ANXIOLYTIC-LIKE EFFECT OF NEUROPEPTIDE Y(NPY) AND NPY13-36 MICROINJECTED INTO VICINITY OF LOCUS-COERULEUS IN RATS

Neuropeptide Y (NPY, 1 and 10 pmol), NPY Y, receptor agonist [Leu(31), Pro(34)]Npy (10 pmol) and Y-2 agonist NPY13-36 (100 pmol) were adminis tered unilaterally into the region of the nucleus locus coeruleus (LC) in rats. NPY (10 pmol) and NPY13-36 increased the percentage of open arm entries, the percentage of time spent on open part, number of both open and closed arm entries and line crossings in the open part while [Leu(31),Pro(34)]Npy failed to modify elevated plus-maze behavior. Th ese data suggest that NPY applied close to LC has anxiolytic-like effe cts by acting on NPY Y-2, not on Y-1 receptors. Thus, NPY Y-2 receptor s in the vicinity of LC may be involved in the regulation of anxiety i n rats. (C) 1998 Elsevier Science B.V.