Neuropeptide Y and Peptide YY Peptides

NPY Inhibition of Catecholamine Release
Catecholamine synthesis and release are two separate but related processes that influence the level of catecholaminergic neurotransmission. Neuropeptide Y (NPY) is a 36 amino acid peptide that is highly homologous to peptide YY (PYY). NPY exerts its various biological effects through at least six classes of receptors, designated as Y1, Y2, Y3, Y4, Y5, and Y6. It has been demonstrated that NPY inhibits catecholamine synthesis via the Y3 receptor subtype, in contrast to the Y2 subtype that mediates inhibition of catecholamine release. Although inhibition of both synthesis and release by these receptor subtypes is via inhibition of Ca2+ entry, the two processes are associated with actions on distinct Ca2+ channel subtypes. Inhibition of L-type Ca2+ channels mediates inhibition of catecholamine synthesis, while inhibition of N-type Ca2+ channels inhibits release.
References:
McCullough, L.A., et al., Neuropeptide Y receptors involved in calcium channel regulation in PC12 cells. Regul. Pept. 75-76, 101-107 (1998).