Abstract
Neuropeptide Y (NPY) receptors are heterogeneous, consisting of at least two subclasses, Y
1 and Y
2. We sought evidence for differential expression of NPY receptor subtypes in the rat brain. Tissue was incubated with
125I-peptide YY (PYY) which labels NPY
and PYY binding sites. The Y
1-selective agonist, p[Pro
34]NPY, and the Y
2-selective agonist, pNPY 13–36, were used as displacing ligands. Autoradiographic analyses of regional receptor binding demonstrated heterogeneity across brain regions. We conclude that Y
1- and Y
2-receptors may be independently expressed in the brain. While the predominate NPY/PYY receptor subtype in the brain is Y
2, there are also Y
1-receptors in some brain regions such as the superficial layers of the parietal cortex.
