bioRxiv (Cold Spring Harbor Laboratory)
September 26, 2023
Yi-Ting Chiu, Wei Wang, Pierre Llorach et al.
15 citations
preprint
Psychedelic drugs such as LSD and psilocybin show promise as treatments for depression, anxiety, PTSD, migraine, and cluster headaches by activating the 5-HT2A receptor (HTR2A). Researchers engineered several new mouse lines to study the role of HTR2A and the neurons that express it. One line allows visualization of the receptor and identification of HTR2A-containing cells, providing a detailed anatomical map. Another line has a humanized version of the receptor, and a third enables targeted genetic manipulation. The mice exhibited expected behavioral responses to psychedelics, confirming their usefulness. Electrophysiology showed that serotonin increases firing of specific pyramidal neurons through HTR2A, consistent with the receptor's location on the cell surface. These tools will help clarify how psychedelics work at molecular, cellular, and behavioral levels.
Biological psychiatry
May 5, 2025
Matthew B Pomrenze, Sam Vaillancourt, Pierre Llorach et al.
11 citations
Ketamine produces a rapid increase in movement (locomotor activation) in mice by acting on mu opioid receptors (MORs) in the central amygdala (CeA). This effect is blocked by the opioid receptor antagonist naltrexone, and the same blockade occurs with a MOR-selective antagonist. Whole-brain imaging showed that naltrexone most strongly altered ketamine-induced cFos expression in the CeA, particularly in neurons that co-express MOR and PKCδ. Interrupting MOR function specifically in the CeA, either with a drug or genetic manipulation, prevented ketamine's locomotor effects. This indicates that ketamine's acute behavioral effects involve opioid signaling in the CeA, which may relate to its antidepressant mechanism in humans.
bioRxiv : the preprint server for biology
October 22, 2024
Matthew B Pomrenze, Sam Vaillancourt, Juliana S Salgado et al.
1 citation
preprint
MDMA releases both dopamine and serotonin in the brain's reward center, the nucleus accumbens, but its strong serotonin release limits dopamine release and abuse potential. Using conditional knockout mice and direct brain infusions, the authors show that MDMA's serotonin release, acting through the serotonin transporter and 5-HT2C receptors, reduces the drug's reinforcing effects and conditioned place preference, while its prosocial effects are mediated by separate mechanisms. This platform predicts that (R)-MDMA, a novel entactogen, will have prosocial effects and low abuse potential.
bioRxiv : the preprint server for biology
March 6, 2024
Matthew B Pomrenze, Sam Vaillancourt, Pierre Llorach et al.
1 citation
preprint
Ketamine's effects on movement in mice are blocked by the opioid receptor antagonist naltrexone, but its analgesic and antidepressant-like effects are not. Whole-brain imaging identified the central amygdala as the region most affected by naltrexone, where neurons expressing mu-opioid receptors and PKCδ were strongly activated by naltrexone but not by ketamine. Disrupting mu-opioid receptor function in the central amygdala, either with drugs or genetic techniques, blocked ketamine's locomotor effects. These results indicate that mu-opioid receptors in the central amygdala gate certain behavioral effects of ketamine without being direct targets of the drug.
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.