text: 5-HT receptors are all G-protein coupled receptors (GPCR) except for 5-HT which is a ligand gated ion channel. The receptors that have been found to be involved in migraine are 5-HT, 5-HT and 5-HT receptors. 5-HT are found in meningeal arteries, agonism of 5-HT causes vasoconstriction in cranial nerves. The 5-HT receptors are located primarily in the trigeminal nerve in the central nervous system (CNS). They are also found in vascular smooth muscles, mediating contraction. Agonism of 5-HT receptors subdues the release of inflammatory inducing nerve stimulants. The amino acids contributing to the binding of ligands to the receptor are aspartic acid (Asp), phenylalanine (Phe), serine (Ser), threonine (Thr), tryptophan (Trp) and tyrosine (Tyr). It has been shown that both 5-HT and 5-HT receptors in humans have a very similar amino acids structures which demonstrates the similarities in binding properties.