Molecular psychiatry
September 1, 2023
Kat F Kiilerich, Joe Lorenz, Malthe B Scharff et al.
48 citations
Repeated low doses of psilocybin, similar to human microdosing, were tested in rats. The regimen was well tolerated, causing no signs of anhedonia, anxiety, or altered movement, and did not downregulate or desensitize 5-HT2A receptors. The treatment increased resilience to injection stress, reduced self-grooming (a proxy for compulsive actions), and raised 5-HT7 receptor expression and synaptic density in the paraventricular nucleus of the thalamus. These findings support anecdotal reports of benefits from psilocybin microdosing and suggest a possible physiological mechanism.
Journal of medicinal chemistry
September 22, 2022
Christian B M Poulie, Eline Pottie, Icaro A Simon et al.
32 citations
The serotonin 2A receptor (5-HT2AR) is responsible for the psychedelic effects of certain drugs, which show promise for treating neuropsychiatric conditions. This work examined how a series of compounds, including 25CN-NBOH, signal through two pathways: Gαq and β-arrestin. Disrupting the interaction with a specific amino acid, Ser1593×36, reduced both pathways' potency and efficacy, with Gαq signaling more strongly affected. This led to the creation of the first effective β-arrestin-biased 5-HT2AR agonists (4a-b and 6e-f), which prefer the β-arrestin pathway over Gαq relative to LSD.
ACS chemical neuroscience
August 2, 2023
Eline Pottie, Christian B M Poulie, Icaro A Simon et al.
25 citations
Serotonergic psychedelics primarily activate the serotonin 2A receptor (5-HT2A), but the molecular basis for their psychedelic effects is not fully understood. A leading hypothesis is biased agonism, where certain signaling pathways are preferentially activated. This study tested a series of 4-position-substituted phenylalkylamines for their ability to recruit β-arrestin2 or miniGαq to the 5-HT2A receptor. All compounds acted as agonists with varying potency and efficacy. Lipophilicity of the 2C-X phenethylamines correlated more strongly with efficacy in the miniGαq assay than the β-arrestin2 assay. Molecular docking suggested that the 4-substituent fits into a hydrophobic pocket between transmembrane helices 4 and 5, potentially explaining this differential effect. Using serotonin and LSD as reference agonists, both benchmark and physiology bias were estimated, and qualitative structure-activity relationships remained consistent across different activation profiles.
ACS chemical neuroscience
May 6, 2020
Emil Marcher-Rørsted, Adam L Halberstadt, Adam K Klein et al.
20 citations
The 2,5-dimethoxy motif found in many phenethylamine psychedelics has been considered essential for activating the serotonin 2A receptor (5-HT2AR). This study synthesized derivatives of 2C-B and DOB lacking either the 2- or 5-methoxy group and tested them in binding and functional assays at 5-HT2AR and 5-HT2CR, as well as in mice for head-twitch response, a behavioral proxy for psychedelic activity. Removing either methoxy group caused a modest drop in binding affinity and functional potency at both receptors, with larger effects from removing the 2-methoxy group. However, in mice, removal of either group drastically reduced head-twitch response. Thus, the 2,5-dimethoxy motif is important for in vivo potency, but this does not correlate with in vitro receptor affinity or potency.