The function of ADCYAP1R1 (ADCYAP receptor type I, Ensembl gene identifier ENSG00000078549) is as follows. G protein-coupled receptor activated by the neuropeptide pituitary adenylate cyclase-activating polypeptide (ADCYAP1/PACAP) (PubMed:32004469, PubMed:32047270, PubMed:33715378, PubMed:35477937, PubMed:36385145). Binds both PACAP27 and PACAP38 bioactive peptides (PubMed:32004469, PubMed:32047270, PubMed:35477937, PubMed:36385145). Ligand binding causes a conformation change that triggers signaling via guanine nucleotide-binding proteins (G proteins) and modulates the activity of downstream effectors. Activates cAMP-dependent pathway (PubMed:32004469, PubMed:32047270, PubMed:33715378, PubMed:35477937, PubMed:36385145). May regulate the release of adrenocorticotropin, luteinizing hormone, growth hormone, prolactin, epinephrine, and catecholamine. May play a role in spermatogenesis and sperm motility. Causes smooth muscle relaxation and secretion in the gastrointestinal tract (PubMed:32047270, PubMed:33715378). {ECO:0000269|PubMed:32004469, ECO:0000269|PubMed:32047270, ECO:0000269|PubMed:33715378, ECO:0000269|PubMed:35477937, ECO:0000269|PubMed:36385145}.