Alterations in neuropeptide Y levels and Y1 binding sites in the Flinders Sensitive Line rats, a genetic animal model of depression

Previously, we observed specific alterations of neuropeptide Y (NPY) and Y1 receptor mRNA expression in discrete regions of the Flinders Sensitive Lin e rats (FSL), an animal model of depression. In order to clarify the correl ation between mRNA expression and protein content, radioimmunoassay and rec eptor autoradiography were currently performed. In the FSL rats, NPY-like i mmunoreactivity (NPY-II) was decreased in the hippocampal CA region, while Y1 binding sites were increased; NPY-LI was increased in the arcuate nucleu s. Fluoxetine treatment elevated NPY-LI in the arcuate and anterior cingula te cortex and increased Y1 binding sites in the medial amygdala and occipit al cortex in both strains. No differences were found regarding the Y2 bindi ng sites. The results demonstrate a good correlation between NPY peptide an d mRNA expression, and sustain the possible involvement of NPY and Y1 recep tors in depression. (C)1999 Elsevier Science Ireland Ltd. All rights reserv ed.