Pituitary adenylate cyclase-activating polypeptide type I receptor also known as PAC<sub>1</sub>, is a protein that in humans is encoded by the ADCYAP1R1 gene. This receptor binds pituitary adenylate cyclase activating peptide.
PAC<sub>1</sub> is a membrane-associated protein and shares significant homology with members of the G-protein coupled class B glucagon/secretin receptor family. This receptor mediates diverse biological actions of adenylate cyclase activating polypeptide 1 and is positively coupled to adenylate cyclase. Alternative splicing of two exons of this gene generates four major splice variants, but their full-length nature has not been determined. PAC<sub>1</sub> is expressed in the adrenal medulla, pancreatic acini, uterus, myenteric plexus and brain. It is also expressed in the trigeminal, otic and superior cervical ganglia (prejunctional) and cerebral arteries (postjunctional).