Psilocybin induces sex- and context-specific recruitment of the stress axis
Bibliographic record
Abstract
Following decades of prohibition, psychedelic drugs have reemerged as promising therapeutics for stress-related conditions, including depression and post-traumatic stress disorder. Still, their impact on stress-related brain regions and the hypothalamic-pituitary-adrenal (HPA) axis remains unclear. This work explores the acute effects of psilocybin on the primary regulators of the HPA axis: corticotropin-releasing hormone neurons in the paraventricular nucleus of the hypothalamus (CRH PVN ). Here, using blood plasma measurements and in vivo single-fiber photometry, we demonstrate that psilocybin induces robust activation of the HPA axis via CRH PVN neurons, with more pronounced responses observed in female mice and a reliance on serotonergic 5-HT2A and 5-HT2C receptors. Ex vivo electrophysiology indicates that the 5-HT2A-receptor-mediated effects involve dual mechanisms: direct post-synaptic depolarization of CRH PVN neurons and increased presynaptic glutamate release. Our findings also reveal that psilocybin alters how CRH PVN neurons react to environmental changes, resulting in a surprising decrease in activity that contrasts with typical elevated stress responses. This context-specific modulation may be a key mechanism underlying the therapeutic potential of psychedelics to recalibrate maladaptive stress reactivity. Our findings emphasize the interplay between the serotonergic and stress systems and support the considerable influence of contextual factors, i.e., "setting," on the psychedelic experience. This study provides the first real-time in vivo evidence of neuronal activation of the stress system following psilocybin administration and has significant implications for optimizing the therapeutic efficacy of psychedelic-assisted therapy.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".