[3][5][4] 5-MT is a highly potent and non-selective serotonin receptor agonist[6][7][8][9] and shows serotonergic psychedelic-like effects in animals.

[11][12][13][14][15][16] 5-MT can be formed by O-methylation of serotonin mediated by hydroxyindole O-methyltransferase (HIOMT) or by N-deacetylation of melatonin.

[18][19][20][21][22][23][24] It is an extremely potent serotonin 5-HT2A receptor agonist in vitro, with an EC50Tooltip half-maximal effective concentration of 0.503 nM.

[3][5] 5-MT shows dramatically reduced activity as a monoamine releasing agent compared to tryptamine and serotonin.

[12][13] In accordance with the potentiation of brain levels of 5-MT by MAOIs, the behavioral effects of centrally administered 5-MT in rats, for instance in the conditioned avoidance response test, are markedly enhanced by MAOIs, including by the dual MAO-A and MAO-B inhibitor iproniazid and by clorgyline and selegiline.

[13] Similarly to rat findings, pineal gland levels of endogenous 5-MT are dramatically elevated by the MAO-A inhibitor clorgyline and by the dual MAO-A and MAO-B inhibitor pargyline in hamsters, and plasma levels of exogenous 5-MT are greatly elevated by these MAOIs as well.

[14] The non-selective MAO-A and MAO-B inhibitor tranylcypromine has been frequently used to potentiate the effects of 5-MT in animal studies.