There are several possible reasons for a change in prolactin levels during migraines, including serotonin hyperfunction as a contributor to dopaminergic dysfunction, hypersensitivity of dopamine receptors based on the observation that migraineurs showed higher prolactin after taking dopaminergic antagonists and the reduced responsiveness of pituitary lactotroph cells to the action of dopaminergic agents (Cavestro et al., 2006). This evidence concerns the gene PRL and migraine disorder.