Pain perception is a complicated process mediated by the nociceptive system in which neurotransmitters such as serotonin (5-HT), hypocretins (HCRT), norepinephrine (NE) and gamma-aminobutyric acid (GABA) are involved (Sicuteri, 1976; Watanabe et al., 2005; Enna and McCarson, 2006).The trigeminovascular nociception involves the hypothalamus; a brain area that plays a role in primary headaches, among which migraine is the most common. This evidence concerns the gene HCRT and migraine disorder.