In situ hybridization of neuropeptide Y (NPY) mRNA in the goldfish brain

The distribution of neurones expressing neuropeptide Y (NPY) mRNA in the brain of the goldfish was investigated using a non-radioactive in situ hybridization technique. Neurones expressing NPY mRNA were located in cell groups previously shown to exhibit NPY immunoreactivity in the ventral telencephalon, thalamus, optic tectum and a region adjacent to the locus coeruleus. In addition, neurones expressing NPY mRNA were observed in the diffuse nucleus of the torus lateralis and in the mesencephalic tegmentum. Our results suggest that in the two latter groups of neurones the rate of transport of NPY from the perikarya is higher, or that NPY is not synthesized at levels detectable by immunocytochemistry.