7-Methoxytryptamine (7-MeO-T or 7-methoxy-T; developmental code name PAL-533) is a serotonin receptor modulator and monoamine releasing agent of the tryptamine family. It is the 7-methoxy derivative of tryptamine.
The drug acts as a full agonist of the serotonin 5-HT2A receptor, with an EC50Tooltip half-maximal effective concentration of 496 nM and an EmaxTooltip maximal efficacy of 107%. It shows 67-fold lower potency as a serotonin 5-HT2A receptor agonist compared to tryptamine itself. In addition to its serotonin 5-HT2A receptor agonism, 7-methoxytryptamine is a serotonin releasing agent (SRA), with EC50 values for induction of monoamine release of 44.6 nM for serotonin, 2,118 nM for dopamine, and 5,600 nM for norepinephrine in rat brain synaptosomes. The effects of 7-methoxytryptamine in rodents have been described.
Tryptamines without substitutions at the amine or alpha carbon, such as tryptamine, serotonin (5-hydroxytryptamine; 5-HT), and 5-methoxytryptamine (5-MeO-T), are known to be very rapidly metabolized and thereby inactivated by monoamine oxidase A (MAO-A) in vivo and to have very short elimination half-lives. However, given intravenously at sufficiently high doses, tryptamine is still known to be able to produce weak and short-lived psychoactive effects in humans.
The chemical synthesis of 7-methoxytryptamine has been described.
7-Methoxytryptamine was first described in the scientific literature by Ernst Späth and Edgar Lederer by 1931. Its pharmacology was subsequently assessed in greater detail in 2014.