[Neuropeptide Y]: Ligand for neuropeptide Y receptor type 1 (NPY1R) and neuropeptide Y receptor type 2 (NPY2R) (PubMed:1321422, PubMed:7592910, PubMed:35165283, PubMed:35507650, PubMed:36525977, PubMed:38882210). Receptor binding induces adenylate cyclase-inhibiting G protein-coupled receptor signaling, resulting in inhibition of cAMP production (PubMed:1321422, PubMed:7592910, PubMed:38882210). Receptor activation by NPY also leads to an increase of intracellular Ca(2+) levels (PubMed:1321422, PubMed:35165283, PubMed:7592910). Is involved in the regulation of eating behaviour, acting as a stimulator of food intake (By similarity). Involved in the regulation of colonic antisecretory tone, and colonic contractility (By similarity). {ECO:0000250|UniProtKB:P07808, ECO:0000250|UniProtKB:P57774, ECO:0000269|PubMed:1321422, ECO:0000269|PubMed:35165283, ECO:0000269|PubMed:35507650, ECO:0000269|PubMed:36525977, ECO:0000269|PubMed:38882210, ECO:0000269|PubMed:7592910}. This is the function of NPY (neuropeptide Y, Ensembl gene identifier ENSG00000122585).