CELLULAR-LOCALIZATION OF NEUROPEPTIDE-Y MESSENGER-RNA AND PEPTIDE IN THE BRAIN OF THE JAPANESE-QUAIL AND DOMESTIC CHICKEN

Neuropeptide Y (NPY) has been implicated in the control of a number of physiological functions in birds including food intake and reproducti on. In the present study, sites of NPY synthesis were localized in the brains of Japanese quail and domestic chickens by in situ hybridizati on histochemistry using a digoxigenin-labelled riboprobe. NPY mRNA was detected in three main cell groups in both species. The most prominen t group was associated with structures in the lateral thalamus includi ng the anterior lateral thalamic nucleus, lateral forebrain bundle, ro tund nucleus, pretectal nucleus and occipitomesencephalic tract. Other major cell groups were detected in the hippocampus, and in the caudal linear nucleus and raphe nucleus of the brainstem. NPY mRNA was also present in the piriform cortex and taenial nucleus. Double-labelling o f NPY mRNA and peptide was demonstrated in individual cells of the hip pocampal, thalamic and brainstem cell groups, suggesting that NPY is s ynthesized and stored in these areas. However, the identity of other c ell groups, notably in the hyperstriatal, archistriatal and neostriata l regions of the telencephalon, which exhibit NPY-immunoreactive cell bodies but no NPY mRNA, remains to be determined.