Nature
January 1, 2021
Lindsay P. Cameron, Robert J Tombari, Ju Lu et al.
468 citations
Ibogaine, a psychedelic alkaloid, shows anti-addictive effects in humans and animals but has safety issues including toxicity and heart arrhythmias. Researchers engineered tabernanthalog, a water-soluble, non-hallucinogenic, non-toxic analogue made in a single step. In rodents, tabernanthalog promoted structural neural plasticity, reduced alcohol- and heroin-seeking behavior, and produced antidepressant-like effects. This demonstrates that careful chemical design can create safer, non-hallucinogenic variants of psychedelic compounds with therapeutic potential.
Science
February 16, 2023
Maxemiliano V. Vargas, Lee E. Dunlap, Chunyang Dong et al.
467 citations
Decreased dendritic spine density in the cortex is a hallmark of several neuropsychiatric diseases, and the ability to promote cortical neuron growth has been hypothesized to underlie the rapid and sustained therapeutic effects of psychedelics. Activation of 5-HT2ARs is essential for psychedelic-induced cortical plasticity, but it is unclear why some 5-HT2AR agonists promote neuroplasticity while others do not. Using molecular and genetic tools, the authors demonstrate that intracellular 5-HT2ARs mediate the plasticity-promoting properties of psychedelics, explaining why serotonin does not engage similar plasticity mechanisms. This work emphasizes location bias in 5-HT2AR signaling, identifies intracellular 5-HT2ARs as a therapeutic target, and raises the possibility that serotonin might not be the endogenous ligand for intracellular 5-HT2ARs in the cortex.
Proceedings of the National Academy of Sciences
April 14, 2025
Jeremy R Tuck, Lee E. Dunlap, Yara A Khatib et al.
32 citations
A newly designed compound, (+)-JRT, structurally similar to LSD but with reduced hallucinogenic effects, promotes the growth of dendritic spines in the cortex—a process that is diminished in neuropsychiatric diseases such as depression, addiction, and schizophrenia. In behavioral tests, (+)-JRT showed antidepressant-like and cognition-enhancing effects without worsening signs related to psychosis. This suggests that nonhallucinogenic compounds that promote neuroplasticity could be safer alternatives to psychedelics for treating conditions where psychedelics pose risks.
ACS Chemical Neuroscience
March 1, 2023
Robert J Tombari, Paige C Mundy, Kelly M Morales et al.
15 citations
Thirteen psychoactive compounds from different chemical classes were screened in larval zebrafish for developmental toxicity. Psychedelic tryptamines and ketamine were less neurotoxic than LSD and psychostimulants. The results provide a reference database for comparing neurotoxicity profiles of novel psychedelics being developed as therapeutics.
Journal of Medicinal Chemistry
June 18, 2025
Alexandra Sink, Eline Pottie, Samuel J Carter et al.
2 citations
A photoswitchable ligand for the serotonin 2A receptor (5-HT2AR) was designed to independently study G protein- and β-arrestin2-dependent signaling pathways. The cis-photoisomer binds the receptor with greater affinity than the trans-isomer, at nanomolar concentrations. In functional assays, this ligand showed a preference for recruiting β-arrestin2 over mini-Gαq relative to LSD, offering a tool to investigate β-arrestin2's role in 5-HT2AR signaling and its potential involvement in psychedelic effects.
ACS Chemical Neuroscience
May 6, 2026
Maxemiliano V. Vargas, Cassandra J. Hatzipantelis, Lee E. Dunlap et al.
A safer analogue of MDMA, called R-MDDMA, shows promise for treating PTSD and depression without the abuse potential of MDMA. Unlike MDMA, R-MDDMA does not activate 5-HT2B receptors, induce serotonin release, cause head-twitch responses, affect body temperature, or increase locomotion at therapeutic doses. However, it still promotes structural neuroplasticity in cortical neurons, facilitates fear extinction learning, and produces sustained antidepressant-like effects. These results suggest that R-MDDMA might be a safer MDMA analogue with similar therapeutic properties.