The Vasoactive intestinal Peptide/Pituitary Adenylate Cyclase Activating Polypeptide (VPAC) receptor is G protein-coupled and has been divided into at least three types: PAC1, VPAC1, and VPAC2. High expression of PAC1 is observed in CNS and the adrenal medulla. Several splice variants of PAC1 result in proteins that differ at the N-terminus and third intracellular loop; these variants differ in their affinities for PACAP and abilities to activate Gq and Gs. This manual describes establishment of a cell line and a protocol of pharmacologically validated human PAC1 GPCR receptor (Genebank Accession Number: NM_003382).