In recent years, however, there are results challenging the importance of only dilatation of dural vessels as the primary mechanism behind migraine, for example not all MMA (Middle Meningeal Artery) vasodilators cause migraine-like attacks e.g. acetylcholine/carbachol and VIP (Vasoactive Intestinal Peptide) [3], [4]. This evidence concerns the gene VIP and migraine disorder.