Pharmacological characterization of VIP and PACAP receptors in the human meningeal and coronary artery

Objective: We pharmacologically characterized pituitary adenylate cyclase-activating polypeptides (PACAPs), vasoactive intestinal peptide (VIP) and the VPAC(1), VPAC(2) and PAC(1) receptors in human meningeal (for their role in migraine) and coronary (for potential side effects) arteries. Methods: Concentration response curves to PACAP38, PACAP27, VIP and the VPAC(1) receptor agonist ([Lys15, Arg16, Leu27]-VIP[1-7]-GRF[8-27]) were constructed in the absence or presence of the PAC(1) receptor antagonist PACAP6-38 or the VPAC1 receptor antagonist, PG97269. mRNA expression was measured using qPCR. Results: PACAP38 was less potent than VIP in both arteries. Both peptides had lower potency and efficacy in meningeal than in coronary arteries, while mRNA expression of VPAC(1) receptor was more pronounced in meningeal arteries. PACAP6-38 reduced the E-max of PACAP27, while PG97269 right-shifted the VIP-induced relaxation curve only in the coronary arteries. Conclusion: The direct vasodilatory effect of VIP and PACAP might be less relevant than the central effect of this compound in migraine pathogenesis.