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 Y1 receptor agonist [Leu31, Pro34]NPY (10 pmol) and Y2 agonist NPY13-36 (100 pmol) were administered 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 [Leu31,Pro34]NPY failed to modify elevated plus-maze behavior. These data suggest that NPY applied close to LC has anxiolytic-like effects by acting on NPY Y2, not on Y1 receptors. Thus, NPY Y2 receptors in the vicinity of LC may be involved in the regulation of anxiety in rats. Copyright 1998 Elsevier Science B.V.