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).