4-F-5-MeO-pyr-T, also known as 4-fluoro-5-methoxy-N,N-pyrrolidinyltryptamine, is a serotonin 5-HT<sub>1A</sub> receptor agonist of the tryptamine and pyrrolidinylethylindole families. It is a derivative of pyr-T and 5-MeO-DMT.
4-F-5-MeO-pyr-T acts as a highly potent and selective serotonin 5-HT<sub>1A</sub> receptor full agonist. It shows about 813-fold selectivity in activating this receptor over the related serotonin 5-HT<sub>2A</sub> receptor. The drug shows little activity at other serotonin receptors besides the serotonin 5-HT<sub>1A</sub> receptor and little activity at the serotonin transporter (SERT) or other monoamine transporters (MATs).
4-F-5-MeO-pyr-T does not produce the head-twitch response, a behavioral proxy of psychedelic effects, in rodents, and this is the case regardless of whether it is administered alone or in combination with the serotonin 5-HT<sub>1A</sub> receptor antagonist WAY-100635. Likewise, 4-F-5-MeO-pyr-T does not substitute for the psychedelics DOI and LSD in animal drug discrimination tests. However, it fully substitutes for the serotonin 5-HT<sub>1A</sub> receptor full agonist LY-293284 in such tests. 4-F-5-MeO-pyr-T produces serotonin 5-HT<sub>1A</sub> receptor-dependent antidepressant-like effects in rodents. It also dose-dependently produces hypolocomotion in rodents. At higher doses, 4-F-5-MeO-pyr-T induces a pronounced serotonin syndrome and behavioral disruption in rodents, including flat body posture and forepaw treading.
4-F-5-MeO-pyr-T is a potential alternative to 8-OH-DPAT as a serotonin 5-HT<sub>1A</sub> receptor agonist for use in scientific research.
4-F-5-MeO-pyr-T was first synthesized and described by David E. Nichols and colleagues in 2001.