The serotonergic psychedelics psilocybin, LSD and DMT hold great promise for the development of new treatments for psychiatric conditions such as major depressive disorder, addiction and end-of-life anxiety. Previous studies in both animals and humans have confirmed the effects of these drugs on neuronal activity and plasticity. However, the understanding of the mechanisms of action of these substances is limited. Here we show rapid effects of psychedelics on presynaptic properties, using live cell imaging at the level of single synapses in primary rat cortical neurons. Using the genetically encoded reporter of synaptic vesicle fusion synaptopHluorin, we detected a reduced fraction of synaptic vesicles that fused in response to mild or strong electrical stimulation 3-30 min after application of serotonergic psychedelics. These effects were transient and no longer present 24 h after treatment. While DMT only reduced the total recycling pool, LSD and psilocin also reduced the size of the readily releasable vesicle pool. Imaging with the sensors for glutamate, iGluSnFR, and presynaptic calcium, synGCaMP6, showed that while psilocin and DMT increased evoked glutamate release, LSD and psilocin reduced evoked presynaptic calcium levels. Interestingly, psilocin also affected short-term plasticity leading to a depression of responses to paired stimuli. The rapid and drug-specific modulation of glutamatergic neurotransmission described in this study may contribute to distinct anxiolytic and antidepressant properties of serotonergic psychedelics.

• Keywords
• 5‐HT2A, fluorescent sensors, neurotransmitter release, presynaptic, short‐term plasticity, synaptic vesicles,
• MeSH
• Hallucinogens * pharmacology   MeSH
• Rats MeSH
• Cells, Cultured MeSH
• Glutamic Acid * metabolism   MeSH
• Lysergic Acid Diethylamide pharmacology   MeSH
• Cerebral Cortex * drug effects   cytology   metabolism   MeSH
• Neurons * drug effects   metabolism   MeSH
• Rats, Sprague-Dawley MeSH
• Psilocybin pharmacology   MeSH
• Serotonin MeSH
• Synaptic Vesicles drug effects   metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Hallucinogens * MeSH
• Glutamic Acid * MeSH
• Lysergic Acid Diethylamide MeSH
• Psilocybin MeSH
• Serotonin MeSH

Psilocybe cubensis, a widely recognized psychoactive mushroom species, has played a significant role in both historical and modern therapeutic practices. This review explores the complex interplay between genetic diversity, strain variability and environmental factors that shape the biosynthesis of key psychoactive compounds, including psilocybin and psilocin. With many strains exhibiting substantial variability in their phenotypic characteristics and biochemical content, understanding and documenting this diversity is crucial for optimizing therapeutic applications. The review also highlights advances in cultivation techniques, such as submerged fermentation of the mycelium, and innovative analytical methodologies that have improved the precision of compound quantification and extraction. Although there is limited scientific information on P. cubensis due to nearly four decades of regulatory restrictions on psychedelic research, recent developments in genetic and biochemical studies are beginning to provide valuable insights into its therapeutic potential. Furthermore, this review emphasizes key knowledge gaps and offers insights into future research directions to advance the cultivation, scientific documentation of strain diversity, regulatory considerations and therapeutic use of P. cubensis.

• Keywords
• Psilocybe, fungi, genetics, mushroom, mycelium, psilocin, psilocybin, psychoactive,
• Publication type
• Journal Article MeSH
• Review MeSH