Proceedings of the National Academy of Sciences
January 25, 2021
Danilo de Gregorio, Jelena Popić, Justine P. Enns et al.
137 citations
Repeated doses of LSD (30 μg/kg daily for 7 days) increase social behavior in male mice without producing antidepressant or anxiety-reducing effects. The prosocial effect requires the integrity of mTORC1 in excitatory glutamatergic neurons of the medial prefrontal cortex (mPFC), as shown by optogenetic inhibition and conditional knockout experiments. LSD potentiates AMPA and 5-HT2A synaptic responses in the mPFC and increases phosphorylation of Akt and mTOR, but does not affect NMDA or 5-HT1A responses. In mice lacking Raptor in GABAergic neurons, LSD still promotes social behavior. The findings suggest that 5-HT2A/AMPA/mTORC1 signaling in mPFC excitatory neurons mediates LSD's prosocial effects, offering a potential target for treating social deficits in autism and social anxiety.
International Journal of Molecular Sciences
November 23, 2016
Danilo de Gregorio, Stefano Comai, Luca Posa et al.
125 citations
LSD produces hallucinogenic and psychotic-like effects through a complex mechanism involving multiple neurotransmitter systems. The primary action occurs in the Dorsal Raphe via the serotonergic system, where LSD acts as a partial agonist at 5-HT2A receptors and an agonist at 5-HT1A receptors. At higher doses, it also stimulates dopamine D2 receptors, Trace Amine Associated Receptor 1 (TAAR1), and 5-HT2A in the Ventral Tegmental Area. This pleiotropic mechanism, engaging serotonergic, dopaminergic, and glutamatergic pathways, makes LSD-induced psychosis a useful preclinical model for testing novel antipsychotic drugs, especially those targeting dual serotonergic and dopaminergic systems or TAAR1 receptors. More human studies are needed to clarify these mechanisms.
Neuropsychopharmacology
March 17, 2022
Danilo de Gregorio, Antonio Inserra, Justine P. Enns et al.
89 citations
Psychedelics like lysergic acid diethylamide (LSD) significantly influence serotonin levels, potentially reshaping our understanding of antidepressants. In a study with 100 participants, 60% reported reduced anxiety after a single dose, highlighting the anxiolytic effects of psychedelics on the dorsal raphe nucleus, a key area in serotonergic neurotransmission. Furthermore, alterations in hippocampal activity were observed, suggesting that these substances could enhance emotional processing and behavior. This research opens new avenues for drug studies in pharmacology and psychology, particularly in treating mood disorders.
British journal of pharmacology
March 1, 2023
Antonio Inserra, Giada Giorgini, Sebastien Lacroix et al.
38 citations
Repeated doses of LSD increase social behavior in male mice and alter brain chemistry and gut bacteria. LSD raised social preference and novelty seeking. In the hippocampus, LSD lowered several endocannabinoid-like compounds, including anandamide and related N-acylethanolamines, certain monoacylglycerols, prostaglandins, thromboxane, and kynurenine. The prefrontal cortex showed fewer changes. LSD also reduced the diversity of gut bacteria, prevented a shift in the Firmicutes:Bacteroidetes ratio, and changed the abundance of specific bacterial groups such as Bifidobacterium. These findings suggest that the prosocial effects of LSD involve the hippocampal endocannabinoidome and kynurenine pathway, along with gut microbiome alterations.
Progress in neuro-psychopharmacology & biological psychiatry
August 30, 2024
Antonella Campanale, Antonio Inserra, Stefano Comai
18 citations
The kynurenine pathway (KP) plays a crucial role in the altered gut-brain axis balance in severe mental illness (SMI), including depression, bipolar disorder, and schizophrenia, as well as in cardiometabolic comorbidities. Serotonergic psychedelics may hold therapeutic potential by modulating the KP, either directly through influencing rate-limiting enzymes and tryptophan levels, or indirectly via effects on the gut microbiome, metabolism, and immune system. Preliminary evidence suggests psychedelics improve outcomes in preclinical models of obesity, metabolic syndrome, and vascular inflammation. However, the mechanisms and outcomes remain largely unknown, and concerns about side effects in specific SMI cohorts require further investigation.
Trends in Pharmacological Sciences
September 16, 2025
Sonia Sonda, Diana Pendin, Stefano Comai et al.
11 citations
Psilocybin, a serotonergic psychedelic, shows rapid and lasting therapeutic effects for depression and other hard-to-treat neuropsychiatric conditions, likely due to its ability to enhance neuronal plasticity. While these effects are often attributed to activation of the serotonin 2A (5-HT2A) receptor, emerging evidence indicates a more complex pharmacological profile involving multiple serotonin receptor subtypes and non-serotonergic targets like TrkB. This review integrates current findings on the molecular interactome of psilocin, the active metabolite of psilocybin, focusing on receptor selectivity, biased agonism, and intracellular receptor localization. These insights provide a refined framework for understanding psilocybin's enduring effects and guiding the development of next-generation neuroplastogens with improved specificity and safety.
Molecular psychiatry
February 1, 2025
Jacopo Sapienza, Francesca Martini, Stefano Comai et al.
11 citations
Despite promising results in other psychiatric conditions, no modern clinical trials have tested psychedelics in patients with schizophrenia, except for semi-anecdotal studies from the 1950s and 1960s that noted improvements in negative symptoms and social cognition. Recent evidence suggests the mechanisms of psychedelics partially overlap with schizophrenia's pathology but in an opposite direction, providing a biological rationale for their use. This perspective paper reviews old experiments and recent molecular findings on neuroplasticity, connectivity, immune and TAARs systems, neurotransmitters, and neurotropic factors. The authors identify a therapeutic potential for negative symptoms and social cognition, proposing very low doses (microdosing) for a subpopulation of chronic patients predominantly burdened by negative symptoms, while carefully considering safety and feasibility to guide future trials.
Cellular signalling
March 1, 2025
Etienne Billard, Alexandre Torbey, Antonio Inserra et al.
10 citations
Cannabidiol (CBD) can block the activation of the serotonin receptor 5-HT2A by psychedelic compounds like LSD, without affecting another signaling pathway linked to the receptor. In human embryonic kidney cells and rat neurons, CBD reduced LSD's ability to trigger Gq protein signaling, a key step in the receptor's effects. Computer simulations suggested CBD binds to a different site on the receptor than LSD, overlapping with a known positive modulator. The findings indicate CBD acts as a negative allosteric modulator of 5-HT2A, potentially offering a way to reduce hallucinations while preserving therapeutic benefits of psychedelics.
Pharmacological Research
December 29, 2025
Martina Colognesi, Daniela Gabbia, Anna Signor et al.
3 citations
Chronic low-dose psilocybin (0.05 mg/kg) reduced body-weight gain, liver steatosis, hyperglycemia, and insulin resistance in mice fed a high-fat/high-fructose diet, without causing central nervous system effects. Multi-omics analyses showed near-complete normalization of disrupted hepatic lipid and carbohydrate metabolism pathways. Psilocybin also improved muscle strength and function, potentially through restoration of leptin sensitivity. The metabolic benefits were independent of the psychedelic target 5-HT2A and instead resulted from antagonism of the serotonin 5-HT2B receptor in the liver, supporting psilocybin as a potential novel therapeutic for metabolic disorders.
International journal of molecular sciences
September 14, 2025
Jacopo Sapienza, Marco Spangaro, Stefano Comai et al.
2 citations
Schizophrenia involves excessive loss of brain connections, partly due to overactive microglia that prune synapses. A genetic variant in complement component 4 (C4) is strongly linked to the disease and drives this pruning. Brain scans using a new tracer for synaptic vesicle glycoprotein 2A (SV2A) confirm lower synaptic density in the prefrontal cortex of people with schizophrenia, supporting the synaptic hypothesis. Psychedelics like LSD and psilocybin promote neuroplasticity and synaptogenesis in animal and lab studies, potentially counteracting synaptic loss and improving negative and cognitive symptoms. The authors suggest starting with microdoses in deficit schizophrenia patients, then escalating if results are positive.
Journal of Medicinal Chemistry
January 26, 2026
Marco Banzato, Martina Colognesi, Lorena Lucatello et al.
A library of fluorinated reversible N-alkyl carbamate derivatives of psilocin was designed and synthesized to reduce acute psilocin exposure and limit hallucinogenic-like effects. By varying the number and positioning of fluorine atoms on the alkyl promoiety, carbamate bond stability was systematically modulated, yielding compounds with finely tuned hydrolysis under physiological conditions. A lead compound (4e) demonstrated favorable oral bioavailability and efficient brain penetration while undergoing partial bioconversion to psilocin. It exhibited intrinsic serotonergic activity at 5-HT2A and 5-HT2C receptors but induced attenuated psychotropic effects compared to psilocybin. Fluorinated carbamate chemistry provides a versatile platform to control psilocin exposure and serotonergic signaling.
The International Journal of Neuropsychopharmacology
February 1, 2025
Sofia Nasini, Sara Tidei, Benedetta Barzon et al.
Repeated low-dose psilocybin (0.05 mg/kg) given to adult male mice for 30 days was safe and well tolerated, with no effect on body weight. The treatment produced anxiolytic-like effects: mice spent more time in the light compartment of the light/dark box, showed shorter latency to choose the first arm in the T-maze, and reduced grooming in the open field. No changes were seen in the elevated plus maze, forced swim test, or sociability test. In the cued Morris water maze, psilocybin-treated mice reached the submerged platform faster across all three days and made more successful trials on days 1 and 2, suggesting possible enhancement of spatial memory and learning that requires further study.