α-Ethyltryptamine ( αET, AET), also known as etryptamine ( INN, BAN, USAN), is a psychedelic, stimulant, and entactogenic drug of the tryptamine class.  It was originally developed and marketed as an  antidepressant under the brand name Monase by Upjohn in the 1960s.
Originally believed to exert its effects predominantly via
monoamine oxidase inhibition, alpha-ethyltryptamine was developed during the 1960s as an antidepressant by Upjohn chemical company in the United States under the name Monase, but was withdrawn from potential commercial use due to incidence of idiosyncratic agranulocytosis.
α-ET gained limited recreational popularity as a
designer drug in the 1980s. Subsequently, in the USA it was added to the Schedule I list of illegal substances in 1993.
structurally and pharmacologically related to αMT, α-methyltryptamine, and it is believed its central stimulant activity is probably not due to its activity as an  MAOI, but appears to stem from its structural relationship to the indolic psychedelics. In contrast to αMT, αET is less stimulating and hallucinogenic, its effects resembling more those of entactogens like MDMA ("Ecstasy").
Similarly to α-MT, α-ET is a
releasing agent of serotonin, norepinephrine and dopamine, with serotonin being the primary neurotransmitter affected. In addition, it acts as a non-selective  serotonin receptor agonist. A study performed in 1991 with  rat subjects provided evidence that a-ET may induce serotonergic neurotoxicity similar to that of MDMA. As with many other serotonin releasing agents, injury can occur when excessive doses are taken or when combined with drugs such as other MAOIs.
". "Erowid AET (alpha-ethyltryptamine) Vault ""
Alexander Shulgin; Ann Shulgin. ". #11, a-ET: Alpha-Ethyltryptamine; Indole,3-(2-Aminobutyl); Tryptamine,Alpha-Ethyl; 3-(2-Aminobutyl)Indole; Monase," . Erowid Online Library. p. 11 "Tryptamines i Have Known And Loved: The Continuation", Part 2, "The Chemistry Continues" . Retrieved . 15 November 2013
US Patent 3296072, Szmuszkovicz Jacob, " Method of Treating Mental Depression", published 1967-01-03, assigned to Upjohn Co
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Alexander Shulgin; Ann Shulgin (1997). "" Part 2, The Chemistry Continues: #11, a-ET: Alpha-Ethyltryptamine; Indole,3-(2-Aminobutyl); Tryptamine,Alpha-Ethyl; 3-(2-Aminobutyl)Indole; Monase," part v, "EXTENSIONS AND COMMENTARY."" (Book). Tryptamines i Have Known and Loved: The Continuation, (1st. ed.). Berkeley, CA : Transform Press, ©1997. ISBN 978-0-9630096-9-2 . Retrieved . 15 November 2013 This base, a-ET or etryptamine, was a promising anti-depressant, explored clinically as the acetate salt by Upjohn under the name of Monase. Its central stimulant activity is probably not due to its monoamineoxidase inhibition activity, but appears to stem from its structural relationship to the indolic psychedelics. It was withdrawn from potential commercial use with the appearance of an unacceptable incidence of a medical condition known as agranulocytosis, but the extra mural research into its action, among the lay population, goes on,
Blough, Bruce E.; Landavazo, Antonio; Partilla, John S.; Decker, Ann M.; Page, Kevin M.; Baumann, Michael H.; Rothman, Richard B. (2014). "Alpha-ethyltryptamines as dual dopamine–serotonin releasers". Bioorganic & Medicinal Chemistry Letters. 24 (19): 4754–4758. doi: 10.1016/j.bmcl.2014.07.062. ISSN 0960-894X. PMC . 4211607 PMID 25193229.
Huang XM, Johnson MP, Nichols DE (July 1991). " Reduction in brain serotonin markers by alpha-ethyltryptamine (Monase)". European Journal of Pharmacology. 200 (1): 187–190. doi: 10.1016/0014-2999(91)90686-K. PMID 1722753.
Gillman, P. K. (2005). "Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity". British Journal of Anaesthesia. 95 (4): 434–441. doi: 10.1093/bja/aei210. PMID 16051647. " Drugs such as MDMA, ecstasy (3,4-methylenedioxymethamphetamine), if combined with MAOIs (including moclobemide) do also cause fatalities because they act as serotonin releasers,"