α-Methylserotonin (αMS), also known as α-methyl-5-hydroxytryptamine (α-methyl-5-HT) or 5-hydroxy-α-methyltryptamine (5-HO-αMT), is a tryptamine derivative closely related to the neurotransmitter serotonin (5-HT). It acts as a non-selective serotonin receptor agonist and has been used extensively in scientific research to study the function of the serotonin system.

Pharmacology

αMS is a non-selective and near-full agonist of the serotonin 5-HT2 receptors. It has similar affinity for the 5-HT2A, 5-HT2B, and 5-HT2C receptors. The drug is also a ligand of the serotonin 5-HT1 receptors with high affinity, including of the serotonin 5-HT1A, 5-HT1B, and 5-HT1D receptors (Ki = 40–150nM), but not of the serotonin 5-HT1E receptor (Ki > 10,000nM). In addition to its actions at the serotonin receptors, αMS has been found to act as a norepinephrine releasing agent similarly to α-methylphenylalanine and to other α-alkylated tryptamines. Unlike serotonin, αMS is not metabolized by monoamine oxidase on account of the α-methyl substituent blocking the enzyme's access to the amine. As a result, it has a much longer half-life in comparison. Similarly to serotonin however, αMS poorly crosses the blood-brain-barrier due to its free hydroxyl group, and thus has only weak or no central effects when administered peripherally.

Chemistry

αMS, also known as α-methyl-5-hydroxytryptamine (α-methyl-5-HT), is a substituted tryptamine derivative and the α-methylated analogue of serotonin (5-hydroxytryptamine or 5-HT). The predicted log P (XLogP3) of αMS is 0.6.

Legal status

United States

αMS is not scheduled at the federal level in the United States, but it could be considered an analogue of α-methyltryptamine (AMT), in which case, purchase, sales, or possession could be prosecuted under the Federal Analog Act.

Florida

αMS is a Schedule I controlled substance in the state of Florida making it illegal to buy, sell, or possess in Florida.

Other drugs

α-Methyltryptophan (αMTP) and α-methyl-5-hydroxytryptophan (α-Me-5-HTP) are prodrugs of αMS which cross the blood–brain barrier and thus efficiently deliver αMS into the central nervous system. As a result, these compounds act as orally bioavailable false or substitute neurotransmitters for serotonin, and have been suggested as possible therapeutic agents in the treatment of disorders where serotonin is deficient. The O-methylated analogue of αMS, 5-MeO-αMT, also readily enters the brain, and could be used for such purposes as well.