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.
Cell
April 28, 2021
Chunyang Dong, Calvin Ly, Lee E. Dunlap et al.
207 citations
A genetically encoded fluorescent sensor called psychLight, based on the 5-HT2A receptor structure, detects behaviorally relevant serotonin release and correctly predicts whether structurally similar 5-HT2AR ligands will cause hallucinogenic behavioral effects. Using psychLight, a non-hallucinogenic psychedelic analog was identified that produced rapid-onset and long-lasting antidepressant-like effects after a single administration. The sensor enables in vivo detection of serotonin dynamics, early identification of designer drugs of abuse, and development of non-hallucinogenic therapeutics targeting the 5-HT2AR.
Frontiers in Psychiatry
October 4, 2021
Maxemiliano V. Vargas, Retsina Meyer, Arabo A. Avanes et al.
162 citations
Psychedelics, part of a broader class called psychoplastogens, promote structural and functional neural plasticity in brain circuits relevant to mental health. They produce lasting therapeutic effects after a single dose and show promise for depression, PTSD, anxiety, and substance use disorders. A theoretical framework explains their broad efficacy. Challenges like scalability and hallucinogenic effects may be addressed by non-hallucinogenic psychoplastogens. This shift in neuropsychiatry aims to cure mental illness by repairing underlying pathophysiology, not just treating symptoms.
ACS Pharmacology & Translational Science
September 11, 2020
Calvin Ly, Alexandra C. Greb, Maxemiliano V. Vargas et al.
127 citations
Cortical neuron atrophy, including neurite retraction and spine loss, is a hallmark of depression. Psychoplastogens are small molecules hypothesized to reverse these changes. Ketamine and LSD, from two structurally distinct chemical classes, promote sustained growth of cortical neurons after brief stimulation. This growth occurs in two phases: an initial stimulation phase requiring TrkB activation, followed by a growth period needing sustained mTOR and AMPA receptor activation. These temporal details suggest that rapidly excreted psychoplastogens could be effective neurotherapeutics with advantages over ketamine and LSD.
ACS Chemical Neuroscience
February 1, 2023
Lindsay P. Cameron, Seona D Patel, Maxemiliano V. Vargas et al.
113 citations
Activation of serotonin 2A receptors (5-HT2ARs) is essential for tryptamine-based psychedelics to produce antidepressant-like effects in rodents. While hallucinogenic properties are generally attributed to 5-HT2AR activation, it was unclear whether these receptors also mediate antidepressant effects, especially because some nonhallucinogenic analogues show antidepressant-like properties. Using pharmacological and genetic tools, the authors demonstrate that 5-HT2AR activation is required for the antidepressant-like effects of tryptamine psychedelics, suggesting that hallucinogenic and therapeutic effects can arise through the same receptor.
Psychopharmacology
May 14, 2024
Mazen A Atiq, Matthew R Baker, Jennifer L. Vande Voort et al.
12 citations
Classic psychedelics show therapeutic promise for neuropsychiatric disorders, partly through acute subjective effects (ASE) like mystical-type insights that correlate with long-term benefits. However, barriers such as high resource demands and exclusion of at-risk patients drive a search for compounds that retain therapeutic effects without ASE. Recognizing that psychedelics promote neuroplastic changes correcting aberrant neural circuitry, researchers are developing 'non-psychedelic' psychoplastogens that lack hallucinogenic activity yet show efficacy in preclinical models. This review examines clinical and preclinical evidence on whether ASE can be dissociated from sustained therapeutic properties and proposes clinical scenarios to clarify this question.
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.