Neuropeptide Y and peptide YY do not bind to brain sigma and phencyclidine binding sites

The binding of neuropeptide Y (NPY) and peptide YY (PYY) to sigma and phencyclidine (PCP) receptors in brain membranes was studied. NPY and PYY at up to 500 nM did not bind to sigma or PCP receptors under different binding conditions including different temperatures, membrane preparations, protease inhibitor and sources of the peptides. These findings are in contrast with the reported potent affinities of NPY and PYY for sigma and PCP receptors by Roman et al. (1989, European J. Pharmacol. 174, 301).