Extended Data Fig. 3: Bona fide nonhallucinogenic psychoplastogens promote cortical plasticity in vitro through activation of 5-HT2A receptors.
(a) Maximum numbers of crossings (Nmax) of Sholl plots obtained from rat embryonic cortical neurons (DIV6) treated with compounds (1 μM). Data for hallucinogens and their nonhallucinogenic congeners are shown in red and blue, respectively. Box plots depict the median, interquartile range, and minimum/maximum. Compound-induced dendritogenesis is blocked by pre-treatment with ketanserin (KETSN) (10 μM). (b) Representative images of rat embryonic cortical neurons treated with psychoplastogens in the presence and absence of KETSN. (c) Maximum numbers of crossings (Nmax) of Sholl plots obtained from wild type (WT) and 5-HT2AR KO mouse embryonic cortical neurons (DIV6) treated with compounds (10 μM). (d) Maximum numbers of crossings (Nmax) of Sholl plots obtained from rat embryonic hippocampal neurons (DIV6) treated with compounds (10 μM). BDNF (50 ng/mL) was used as a positive control. (e–g) Maximum numbers of crossings (Nmax) of Sholl plots obtained from rat embryonic cortical neurons (DIV6) treated with hallucinogenic and nonhallucinogenic serotonergic psychoplastogens (1 μM) for 72 h in the presence or absence of various blocking agents (10 μM). (e) Inhibition of mTOR with rapamycin, (f) TrkB with ANA-12, or (g) AMPA receptors with DNQX prevents psychoplastogen-induced neuronal growth. Numbers within bar graphs indicate the number of neurons analyzed per treatment. (h) Spinogenesis induced by LSD and LIS in cortical cultures is blocked by co-treatment with KETSN. (i) Representative images of secondary branches of rat embryonic cortical neurons (DIV21) after compound treatment (1 μM) with or without KETSN (10 μM) pre-treatment. VEH = vehicle; LSD = lysergic acid diethylamide; LIS = lisuride; DMT = N,N-dimethyltryptamine; 6-F-DET = 6-fluoro-N,N-diethyltryptamine; 5-MeO = 5-methoxy-N,N-dimethyltryptamine; TBG = tabernanthalog, KETSN = ketanserin. Boxplots represent median, first quartile, third quartile, and min/max values. Bar graphs represent mean ± s.e.m. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, as compared to VEH controls or VEH – blocker controls, calculated using a one-way ANOVA with Dunnett’s post hoc test (a, c, d, e, f, g, h). For additional details on statistics, see Table S4.
