1-Methyltryptamine

1-Methyltryptamine (1-methyl-T, 1-MT or 1-Me-T; code name PAL-637) is a serotonin receptor agonist and monoamine releasing agent of the tryptamine family. It is the 1-methyl derivative of tryptamine (T; PAL-235).

The drug is known to act as a serotonin 5-HT_2A receptor agonist (K_i = 473 nM; EC₅₀Tooltip half-maximal effective concentration = 209–4,560 nM; E_maxTooltip maximal efficacy = 55–99%), as a serotonin releasing agent (EC₅₀ = 53.1 nM), and to be inactive in inducing the release of norepinephrine and dopamine (EC₅₀ = >10,000 nM). Its activities at other serotonin receptors were not reported. 1-Methyltryptamine shows dramatically reduced affinity and activational potency as well as reduced efficacy at the serotonin 5-HT_2A receptor compared to tryptamine (which showed K_i = 13.1 nM; EC₅₀ = 7.36–99 nM; E_max = 101–104%). It also shows slightly reduced potency as a serotonin releasing agent and abolished activity as a releaser of norepinephrine and dopamine relative to tryptamine (which had EC₅₀ = 32.6 nM, 716 nM, and 164 nM, respectively).

Analogues of 1-methyltryptamine, like 1-methylserotonin and 1-iPr-5-MeO-T, have been studied. Similarly to the case of 1-methyltryptamine contrasted with tryptamine, they show dramatically reduced affinities and activational potencies at the human serotonin 5-HT_2A receptor relative to their 1-unsubstituted counterparts (serotonin and 5-methoxytryptamine, respectively).