G-protein coupled receptor for FARP(FMRFamide related peptide) neuropeptides (PubMed:12821653, PubMed:14555955). Activated by FARP neuropeptides flp-18 and flp-21 (PubMed:12821653, PubMed:14555955). Plays a role in modulating social and feeding behavior (PubMed:9741632). Required to modulate locomotion quiescence during the sleep-like state called lethargus, which occurs during molting between larval and adult stages, in part by regulating touch sensitivity (PubMed:23764289, PubMed:27585848). Expressed in neurons, including neurons in the head, the ventral nerve cord, and the preanal ganglion. Belongs to the G-protein coupled receptor 1 family. It has been reported that many phenotypes associated with the Bristol N2 reference allele of npr-1 may reflect a neomorphic gain-of-function sensitivity of the receptor to flp-18 in addition to sensitivity to flp-21.