Pyr-T has been found to showaffinity forserotonin receptors, including theserotonin5-HT1A,5-HT2A and5-HT2C receptors.[4][5] Its affinities (IC50Tooltip half-maximal inhibitory concentration) for these receptors were 30nM for the serotonin 5-HT1A receptor, 110nM for the 5-HT2A receptor, and 750nM for the serotonin 5-HT2B receptor.[4][5] The affinities of pyr-T for the serotonin 5-HT2A and 5-HT2B receptors were similar to but slightly lower than those ofdimethyltryptamine (DMT), whereas its affinity for the serotonin 5-HT1A receptor was 5.7-fold higher than that of DMT and was intermediate between those of DMT and5-MeO-DMT.[4][5] The serotonin 5-HT1A to 5-HT2A receptor affinity ratios in the study were about 0.27 for pyr-T, 0.5 for 5-MeO-DMT, 1.4 forbufotenin, 2.3 for DMT, and 32 forpsilocin.[5]
Pyr-T has been found to produce behavioral changes in animal tests.[2][6][7] It was described as being aspotent asdiethyltryptamine (DET) in rodents, cats, and primates, but that it also had a poor margin of activity relative totoxicity and was unlikely to be tested in humans.[2] It has been found to producehypolocomotion in rodents.[7] Conversely, pyr-T (3mg/kg) failed to acutely produce thehead-twitch response, a behavioral proxy ofpsychedelic effects, in rodents.[7]
Pyr-T was first characterized by Mitzal by 1962.[8] Animaltoxicity testing was later performed by Hunt and Brimblecombe by 1967.[2][6] The effects of pyr-T in humans were described byAlexander Shulgin in his bookTiHKAL in 1997.[1]
^abcdeBrimblecombe RW, Pinder RM (1975). "Indolealkylamines and Related Compounds".Hallucinogenic Agents. Bristol: Wright-Scientechnica. pp. 98–144.ISBN978-0-85608-011-1.OCLC2176880.OL4850660M.The cyclic analogue of DET, 3-(2-pyrrolidinoethyl)indole (4.13), was as active as the parent compound in behavioural tests in rodents, cats, and primates (Brimblecombe, 1967; Hunt and Brimblecombe, 1967; Brad Icy and Johnston, 1970). The compound was effective at doses down to 0·5 mg./kg. (s.c.) in disrupting the ability of monkeys to perform learned responses, but it is active only at levels which approach its lethal dose and it is unlikely to be tested in man. [...] Compounds of interest which have not been tested in man include [...] 5-methoxy-3-(2-pyrrolidinoethyl)indole, which is the most potent tryptamine so far revealed by the open field test, though its high toxicity will preclude tests in man (Brimblecombe, 1967; Hunt and Brimblecombe, 1967).
^abcNichols DE (2018). "Chemistry and Structure-Activity Relationships of Psychedelics".Current Topics in Behavioral Neurosciences. Vol. 36. pp. 1–43.doi:10.1007/7854_2017_475.ISBN978-3-662-55878-2.PMID28401524.Tethering the dialkyl groups into a heterocyclic ring gave mixed results; N-pyrrolidyl had an affinity similar to N,N-dimethyltryptamine (110 vs. 75 nM, respectively), but the affinity for the N-piperidyl was much lower, at 760 nM.
^abcdMcKenna DJ, Repke DB, Lo L, Peroutka SJ (March 1990). "Differential interactions of indolealkylamines with 5-hydroxytryptamine receptor subtypes".Neuropharmacology.29 (3):193–198.doi:10.1016/0028-3908(90)90001-8.PMID2139186.
^abHunt RR, Brimblecombe RW (July 1967). "Synthesis and Biological Activity of Some Ring-Substituted Tryptamines".Journal of Medicinal Chemistry.10 (4):646–648.doi:10.1021/jm00316a027.PMID4962512.
