5-Methyltryptamine

5-MeT is known to act as a potent serotonin 5-HT_2A receptor full agonist, with an EC₅₀Tooltip half-maximal effective concentration of 6.00 nM and an E_maxTooltip maximal efficacy of 100%.^[1][3] In addition, it is known to be a ligand of the serotonin 5-HT_1A,^[4][3] 5-HT_2B,^[2] 5-HT₆,^[3] and 5-HT₇ receptors,^[3] and an agonist of the serotonin 5-HT_1D^[5][6] and 5-HT_2C receptors.^[7][8][9] Similarly to tryptamine and 5-MeO-T, but in contrast to serotonin, 5-MeT shows very low potency as an agonist of the serotonin 5-HT₃ receptor (EC₅₀ = 60,000 nM).^[10] It shows very weak affinity for the dizocilpine (MK-801) site of the NMDA receptor (IC₅₀Tooltip half-maximal inhibitory concentration = 12,000 nM).^[11]

In addition to acting as an agonist of various serotonin receptors, 5-MeT is a monoamine releasing agent (MRA), with high selectivity for induction of serotonin release over induction of dopamine and norepinephrine release (EC₅₀ = 139 nM, >10,000 nM, and >10,000 nM, respectively, in rat brain synaptosomes).^[1] However, its potency for induction of serotonin release in this system is 23-fold lower than its potency as a serotonin 5-HT_2A receptor agonist.^[1]

Tryptamines without substitutions at the amine or alpha carbon, such as tryptamine, serotonin, and 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.^{[12][13][14][15][16][2][17]} However, given intravenously at sufficiently high doses, tryptamine is still known to be able to produce weak and short-lived serotonergic psychedelic effects in humans.^{[18][13][1][17]}

The predicted log P of 5-MeT is 1.84 to 1.9.^[19][20]

• 1-Methyltryptamine
• 2-Methyltryptamine
• 5-Acetyltryptamine (acetryptine)
• 5-Benzyloxytryptamine
• 5-Carboxamidotryptamine
• 5-(Nonyloxy)tryptamine