Pyr-T, also known as N,N-tetramethylenetryptamine or as 3-(2-pyrrolidinoethyl)indole, is a lesser-known serotonin receptor modulator of the tryptamine and pyrrolidinylethylindole families. It is the cyclized derivative of diethyltryptamine (DET) in which the N,N-diethyl groups have been fused into a pyrrolidine ring.
In his 1997 book TiHKAL (Tryptamines I Have Known and Loved), Alexander Shulgin reported neither the dose range nor the duration of the drug. However, individual experiments employed 25 to 50mg orally and 70mg smoked. Pyr-T produced effects including malaise, feeling sick, unpleasantness, salivation, muscle and joint pains, dizziness, feeling high, and uncomfortableness. Hallucinogenic effects, for instance visuals, were either absent or minor.
Pyr-T has been found to show affinity for serotonin receptors, including the serotonin 5-HT<sub>1A</sub>, 5-HT<sub>2A</sub> and 5-HT<sub>2C</sub> receptors. Its affinities () for these receptors were 30nM for the serotonin 5-HT<sub>1A</sub> receptor, 110nM for the 5-HT<sub>2A</sub> receptor, and 750nM for the serotonin 5-HT<sub>2B</sub> receptor. The affinities of pyr-T for the serotonin 5-HT<sub>2A</sub> and 5-HT<sub>2B</sub> receptors were similar to but slightly lower than those of dimethyltryptamine (DMT), whereas its affinity for the serotonin 5-HT<sub>1A</sub> receptor was 5.7-fold higher than that of DMT and was intermediate between those of DMT and 5-MeO-DMT. The serotonin 5-HT<sub>1A</sub> to 5-HT<sub>2A</sub> receptor affinity ratios in the study were about 0.27 for pyr-T, 0.5 for 5-MeO-DMT, 1.4 for bufotenin, 2.3 for DMT, and 32 for psilocin.
Pyr-T has been found to produce behavioral changes in animal tests. It was described as being as potent as diethyltryptamine (DET) in rodents, cats, and primates, but that it also had a poor margin of activity relative to toxicity and was unlikely to be tested in humans. It has been found to produce hypolocomotion in rodents. Conversely, pyr-T (3mg/kg) failed to acutely produce the head-twitch response, a behavioral proxy of psychedelic effects, in rodents.
Pyr-T is a pyrrolidinylethylindole and a substituted tryptamine in which the amine moiety has been replaced with a pyrrolidine ring. It can be thought of as a cyclized derivative of diethyltryptamine (DET) in which the N,N-ethyl groups have been connected to form the pyrrolidine ring present in pyr-T.
The chemical synthesis of pyr-T has been described.
Derivatives of pyr-T include 4-HO-pyr-T, 5-MeO-pyr-T, and 4-F-5-MeO-pyr-T. Analogues of pyr-T include pip-tryptamine, 10,11-secoergoline (ñ,N-Pip-T), MPMI, and SN-22, among others.
Pyr-T was first characterized by Mitzal by 1962. Animal toxicity testing was later performed by Hunt and Brimblecombe by 1967. The effects of pyr-T in humans were described by Alexander Shulgin in his book TiHKAL in 1997.