DISTRIBUTION OF THE NEUROPEPTIDE-Y Y2 RECEPTOR MESSENGER-RNA IN RAT CENTRAL-NERVOUS-SYSTEM

Our group has recently reported the expression cloning of the human ne uropeptide Y Y2 receptor DNA and subsequently the cloning of the rat h omologue. These studies have made it possible to localize the mRNA enc oding this NPY receptor subtype in rat tissues. We have, thus, carried out in situ hybridization studies, using radiolabeled oligonucleotide probes to the rat Y2 receptor mRNA, to determine the distribution of Y2 mRNA in rat brain and limited peripheral ganglia. Probe specificity was confirmed by testing antisense and sense probes in transfected ce lls. In rat brain, hybridization signals obtained with the antisense p robes were discrete and were restricted to neuronal profiles in specif ic subregions of the cortex, hippocampus, amygdala, thalamus, hypothal amus, mesencephalon and pens. Among the regions exhibiting the most in tense labeling were the CA3 region of the hippocampus, the arcuate nuc leus of the hypothalamus and layer 3 of the piriform cortex. Other reg ions containing labeled neurons included the medial amygdala, the cent romedial thalamic nucleus, the dorsal raphe, the dorsal motor nucleus of the vagus and the trigeminal ganglion. The present results indicate that the mRNA encoding the Y2 receptor is discretely localized in the rat brain and that the distribution is generally consistent with prev ious radioligand-binding studies. This study should help clarify the r elationship between the Y2 receptor distribution and functional studie s of NPY receptor subtype classification and provides further evidence for the involvement of the Y2 receptor in multiple physiological proc esses. (C) 1997 Elsevier Science B.V.