N,N-dimethyltryptamine compound found in the hallucinogenic tea ayahuasca, regulates adult neurogenesis in vitro and in vivo

The study investigates whether the endogenous and plant-derived psychedelic N,N-dimethyltryptamine (DMT) can modulate adult hippocampal neurogenesis and through which receptor mechanisms. DMT, a constituent of ayahuasca, binds serotonin 5-HT1A/2A receptors and interacts with the sigma-1 receptor (S1R), an endoplasmic reticulum chaperone implicated in stress signaling, cellular protection, and neurogenesis. Adult neurogenesis occurs primarily in the subventricular zone and the subgranular zone (SGZ) of the dentate gyrus (DG) but is markedly reduced in adulthood; its extent in humans is debated. Impaired neurogenesis is observed in neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease, suggesting that enhancing endogenous neurogenesis could be therapeutically beneficial. Building on prior work showing neurogenic effects of other ayahuasca components, the authors aim to determine if DMT regulates adult neurogenesis in vitro and in vivo and to elucidate involvement of S1R versus serotonergic receptors.

DMT is present in various plant species and mammalian tissues (including lung and brain) and has been detected in human blood, urine, and CSF. It can be stored in brain vesicular systems and may be stress-responsive. Pharmacologically, DMT acts as an agonist at 5-HT1A and 5-HT2A GPCRs and binds with lower affinity to the sigma-1 receptor (S1R), a widely distributed ER-resident chaperone enriched in cortex, hippocampus, and striatum. DMT has been proposed as an endogenous S1R ligand. S1R has roles in lipid transport, metabolism, differentiation, stress signaling, cytoprotection, myelination, and neurogenesis. Adult neurogenesis, primarily in the SVZ and SGZ, diminishes after development; its persistence in adult humans remains debated, though some studies report continued neurogenesis with aging. Neurodegenerative and psychiatric conditions frequently show impaired proliferation in neurogenic niches, and dopaminergic deficits can reduce precursor activity. Pharmacological stimulation of neurogenesis is considered a potential therapeutic strategy; several antidepressants may exert efficacy partly via promoting neurogenesis. Prior work by the authors indicated strong neurogenic effects of other ayahuasca constituents, motivating evaluation of DMT’s role.

In vitro studies: Adult male C57BL/6 mice (3 months old) were used under approved ethical protocols (EU directive 2010/63/EEC; RD1386/2018). Neural stem cells (NSCs) were isolated from the SGZ of the hippocampus from 24 mice divided into four pools (six animals per pool). Tissue was dissected, dissociated in DMEM with glutamine, gentamicin, and fungizone, then enzymatically digested (0.1% trypsin-EDTA, 0.1% DNase, 0.1% hyaluronidase, 15 min, 37°C). Cells were seeded (~40,000 cells/cm2) in DMEM/F12 (1:1) with EGF (10 ng/mL), FGF (10 ng/mL), and N2 supplement to form neurospheres (NS) over 1 week. Treatments: Once NS were uniform in stage/size, cultures were treated daily for 7 days under proliferative conditions with vehicle or DMT (1 µM). For receptor involvement, cultures were pretreated 1 h with antagonists (1 µM): BD1063 (sigma-1R), methiothepin (5-HT1A/2A), ritanserin (5-HT2A), or WAY100635 (5-HT1A). Viability was unaffected at these doses. Growth and proliferation: After 7 days, NS number and size were quantified (at least 50 NS per condition; Nikon Digital Sight, SD-L1). Some NS were used for immunoblotting; others were replated on coverslips and exposed to DMT ± antagonist for 24 h under differentiation conditions (1% FBS, no exogenous growth factors) before fixation (4% PFA, ≤20 min) for immunocytochemistry with proliferation markers. Differentiation: Seven-day NS were seeded on poly-L-lysine-coated plates/coverslips and cultured with DMT (1 µM) ± antagonists (1 µM) under differentiation conditions; plate cultures were used for western blots and coverslips for ICC to assess neuronal (βIII-tubulin/TuJ1; MAP-2), astrocytic (GFAP), and oligodendrocytic (CNPase) markers. Western blotting: NS lysed in ice-cold lysis buffer with protease inhibitors; 30 µg protein per lane on 10–12% SDS-PAGE, transferred to nitrocellulose, blocked, probed with primary/secondary antibodies, and quantified across 12 blots from four pools (three experiments/pool). Immunocytochemistry: Fixation (4% PFA), permeabilization (0.1% Triton X-100), incubation with primary antibodies (S1R, NeuN, Ki67, βIII-tubulin, MAP-2, GFAP, CNPase), and fluorescent secondaries (Alexa-488/-647); nuclei stained with DAPI. Confocal imaging (Zeiss LSM710). At least eight NS per condition from four pools were imaged. In vivo neurogenesis: Male mice were housed on a 12 h light–dark cycle. Short-term cohort (n = 5/group) received daily i.p. saline or DMT (2 mg/kg) for 4 days with corresponding antagonists (15 mg/kg) alone or in combination with 5-HT receptor antagonists; BrdU (50 mg/kg i.p.) was given on day 4; sacrifice on day 5. Long-term cohort (n = 5/group) received DMT (2 mg/kg i.p.) every other day ± antagonists for 21 days; BrdU (50 mg/kg) on day 21. All i.p. treatments were administered 1 h after clorgyline (1 mg/kg i.p.). Tissue processing and IHC: Perfusion with 4% PFA; coronal brain sections processed and stained with antibodies against S1R, NeuN, BrdU, doublecortin (DCX). Secondary antibodies AlexaFluor 488/647; sections mounted with Vectashield. Confocal imaging (LSM710). Cell counting: Modified stereology on sections containing SGZ using Fiji; total DG counts estimated by multiplying average labeled cells per section by total number of 30-µm DG-containing sections. Five mice per group; results are means from three experiments with five animals/experiment/group; significance threshold P ≤ 0.01 for these counts. Behavioral studies: DMT (2 mg/kg i.p.) alone or with risperidone (0.2 mg/kg) administered over 21 consecutive days; 12 animals/group; controls received vehicle. Treatments were given 1 h after clorgyline (1 mg/kg i.p.). Animals were sacrificed on day 31. Statistics: No formal sample size calculations; no randomization. One-way ANOVA for most datasets (Figs. 1–5); two-way mixed ANOVA for learning curve and cued learning (Fig. 5); Tukey post hoc with α = 0.05; SPSS v20 used.

• DMT engages the sigma-1 receptor (S1R) in adult hippocampal neural progenitors in vitro: S1R is expressed in murine SGZ-derived neurospheres. DMT treatment for 7 days under proliferative conditions decreased stemness markers (Musashi-1, Nestin, SOX-2), indicating loss of undifferentiated state. This effect was blocked by the S1R antagonist BD1063 but not by serotonergic antagonists (methiothepin, ritanserin, WAY100635). • DMT increases proliferation of neural progenitors in vitro: DMT elevated Ki67+ cell numbers and PCNA protein levels; these proliferative effects were reversed by BD1063, but unaffected by 5-HT1A/2A antagonism. • In vivo, DMT activates the adult neurogenic niche: DMT administration increased proliferation and neuroblast markers in the SGZ/DG (BrdU+, DCX+) and promoted the appearance of NeuN+ newly generated neurons in the granule cell layer, consistent with enhanced neurogenesis. • Cognitive benefits: Mice treated with DMT performed better than vehicle controls in memory tests, suggesting functional relevance of DMT-induced hippocampal neurogenesis. • Receptor mechanism: Across in vitro and in vivo paradigms, S1R antagonism blocked DMT’s neurogenic actions, whereas 5-HT1A/2A receptor blockade did not, indicating a primary S1R-mediated mechanism.

The findings demonstrate that DMT robustly modulates adult hippocampal neurogenesis, decreasing stemness marker expression while increasing proliferation and progression toward neuronal differentiation in SGZ-derived progenitors. In vivo, DMT enhanced SGZ proliferation, neuroblast migration, and generation of NeuN+ granule neurons, which correlated with improved performance in memory tasks. Mechanistically, the S1R antagonist BD1063 prevented DMT-induced changes in stemness and proliferation markers, and serotonergic 5-HT1A/2A receptor antagonists did not, indicating that DMT’s neurogenic effects are predominantly mediated via S1R rather than classical serotonergic pathways. These results address the research question by identifying DMT as a modulator of adult neurogenesis through S1R activation and by linking enhanced neurogenesis to cognitive improvement. Given the impairment of adult neurogenesis in neurodegenerative and psychiatric disorders, targeting S1R with endogenous ligands like DMT or selective S1R modulators could represent a strategy to restore neurogenic capacity and cognitive function.

This work shows that DMT activates the adult hippocampal neurogenic niche, promoting proliferation of NSCs, neuroblast migration, and maturation into new granule neurons, with associated gains in memory performance. The effects are mediated primarily by sigma-1 receptor activation, not 5-HT1A/2A receptors. These results highlight S1R as a key regulator of adult neurogenesis and a potential therapeutic target. Future research should: (1) quantify dose–response and time-course relationships for DMT-induced neurogenesis; (2) dissect downstream S1R signaling pathways in NSCs and niche cells; (3) test efficacy and safety in disease models with impaired neurogenesis (e.g., Alzheimer’s, Parkinson’s); (4) compare DMT with selective non-hallucinogenic S1R agonists; (5) evaluate long-term functional integration and behavioral outcomes; and (6) define translational relevance and safety profiles, including effects of MAO inhibition.

No formal sample size calculation and no randomization were used for animal studies, potentially increasing risk of bias. Sample sizes were modest (n = 5 for many in vivo endpoints). Many mechanistic conclusions derive from rodent in vitro and mouse in vivo models, limiting generalizability to humans. All treatments were administered following clorgyline (MAO inhibitor), which may influence DMT metabolism and pharmacodynamics and act as a confound. Only adult male C57BL/6 mice were used, without sex or strain comparisons. Quantitative behavioral details and full effect sizes are not provided here, and long-term persistence/integration of new neurons was not extensively characterized.