Nat Commun
December 15, 2023
Jason Wallach, Andrew B. Cao, Maggie M. Calkins et al.
153 citations
Serotonergic psychedelics show therapeutic potential, but the specific roles of 5-HT2A receptor signaling pathways are unclear. Researchers developed selective ligands with varying Gq efficacies, including β-arrestin-biased ones. In male mice, 5-HT2A-Gq recruitment efficacy, not β-arrestin2 recruitment, predicted psychedelic potential measured by head-twitch response magnitude. Disrupting Gq-PLC signaling reduced this response, and a threshold Gq activation level was needed for psychedelic-like effects, explaining why partial agonists like lisuride are non-psychedelic. β-arrestin-biased agonists blocked psychedelic effects and caused receptor downregulation and tachyphylaxis. Fine-tuning 5-HT2A Gq-signaling enables development of non-psychedelic 5-HT2A agonists.
ACS Pharmacology & Translational Science
December 14, 2020
Adam K. Klein, Muhammad Chatha, Lauren J. Laskowski et al.
103 citations
The 5-HT2A receptor is the primary target for psilocybin and other serotonergic hallucinogens. Seventeen tryptamines with 4-hydroxy or 4-acetoxy groups and various N,N-dialkyl substituents were tested. All acted as full or partial agonists at 5-HT2 subtypes, with similar potencies at 5-HT2A and 5-HT2B receptors, though bulkier N-alkyl groups reduced potency at 5-HT2C receptors and increased 5-HT2B efficacy. O-acetylation reduced in vitro 5-HT2A potency by 10- to 20-fold without altering efficacy. All compounds induced head twitches in mice, consistent with LSD-like effects. Acetylation had little effect on head-twitch potency, suggesting O-acetylated tryptamines may act as prodrugs deacetylated in vivo. These derivatives have psilocybin-like properties, supporting their classification as psychedelic drugs.
bioRxiv (Cold Spring Harbor Laboratory)
July 31, 2023
Jason Wallach, Andrew B. Cao, Maggie M. Calkins et al.
11 citations
preprint
Serotonergic psychedelics show therapeutic promise, but the specific signaling pathways responsible for their effects have been unclear. Researchers developed a series of 5-HT2A receptor ligands with varying Gq efficacies, including β-arrestin-biased ligands. They found that 5-HT2A-Gq efficacy, not β-arrestin2 efficacy, predicts psychedelic potential, measured by head-twitch response in male mice. Disrupting Gq-PLC signaling reduced this response, and a threshold of Gq activation is needed for psychedelic-like effects, explaining why some partial agonists like lisuride are non-psychedelic. β-arrestin-biased agonists caused receptor downregulation and tachyphylaxis, and showed an anti-psychotic-like profile. This fine-tuning of 5-HT2A signaling can generate ligands distinct from classical psychedelics.