PACAP (1-38), a novel neuropeptide isolated from the bovine hypothalamus is more active than vasoactive intestinal peptide (VIP) in stimulating adenylate cyclase (EC50=7 nM). PACAP 1-38 (10-9 M) increased substance P (SP), gastrin releasing peptide (GRP),
PACAP (6-38), human, ovine, rat TFA is a potent PACAP receptor antagonist with IC50 values of 30 nM, 600 nM, and 40 nM for the PACAP type I receptor, PACAP type II receptor VIP1, and PACAP type II receptor VIP2, respectively.
PACAP (1-27), human, ovine, rat TFA (PACAP 1-27 TFA), an N-terminal fragment of PACAP-38, is an effective PACAP receptor antagonist with IC50 values of 3 nM for rat PAC1, 2 nM for rat VPAC1, and 5 nM for human VPAC2.