The study aim at examining whether Sumatriptan changes the plasma values of the neuropeptides vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase activating peptide (PACAP) and the prostanoids 6-keto-PGF1α, and PGE2, PGD2 og PGF2α.