All tested 5-MeO-tryptamines selectively bind to 5-HT1A receptors over 5-HT2A receptors, with computational docking predicting better interaction in the 5-HT1A binding pocket. These compounds also interact with the serotonin transporter (SERT), where molecular size of the amino group influences affinity. 5-MeO-pyr-T acts as the most potent partial 5-HT releaser. All tryptamines elicit the head twitch response in mice, indicating potential hallucinogenic effects primarily mediated by 5-HT2A receptors, but 5-HT1A activation attenuates this response. Tryptamines producing stronger hypothermic responses via 5-HT1A tend to show lower hallucinogenic effects, highlighting opposing roles of the two receptors. Some compounds with low hallucinogenic effects remain potent 5-HT2A agonists, offering insight into non-hallucinogenic therapeutic ligands.
Many psychoactive compounds primarily interact with high-affinity monoamine transporters, but their interactions with low-affinity, high-capacity transporters like human organic cation transporters (hOCTs) and the plasma membrane monoamine transporter (hPMAT) are understudied. Using radiotracer-based uptake inhibition assays in HEK293 cells, 17 psychoactive substances were tested. Most compounds inhibited hOCT1 and hOCT2 in the low micromolar range, while few affected hOCT3 or hPMAT. Methylphenidate and ketamine selectively inhibited hOCT1 or hOCT2, respectively, and MDMA potently inhibited hOCT1, hOCT2, and hPMAT. Enantiospecific differences were observed for R- and S-α-PVP and R- and S-citalopram. These findings highlight the importance of studying drug interactions with hOCTs and hPMAT for regulating monoamine concentrations and xenobiotic clearance.
Three new chemical variants of MDMA—ODMA, TDMA, and SeDMA—show similar activity at serotonin, dopamine, and norepinephrine transporters but reduced activity at 5-HT2A/2B/2C receptors compared to MDMA. They also differ in liver metabolism, with N-demethylation as the only shared route and no phase II metabolites formed. TDMA showed faster clearance. The analogs interacted more weakly with organic cation transporters and plasma membrane monoamine transporter. These bioisosteres may offer therapeutic alternatives to MDMA with a reduced off-target profile, but further studies are needed to determine if they pose lower risks.
Three new chemical variants of MDMA—ODMA, TDMA, and SeDMA—show similar activity at serotonin and dopamine transporters but reduced activity at serotonin 5-HT2A/2B/2C receptors, which may lower the risk of off-target side effects. They also differ from MDMA in how they are broken down by the liver, with fewer metabolic pathways and no phase II metabolites. The analogs interact more weakly with certain organic cation transporters. These findings suggest the new compounds could be promising therapeutic alternatives to MDMA for conditions like PTSD, though further research is needed to confirm whether they pose lower risks.