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Conn K, Milton LK, Huang K, Munguba H, Ruuska J, Lemus MB, Greaves E, Homman-Ludiye J, Oldfield BJ, Foldi CJ. Psilocybin restrains activity-based anorexia in female rats by enhancing cognitive flexibility: contributions from 5-HT1A and 5-HT2A receptor mechanisms. Mol Psychiatry 2024:10.1038/s41380-024-02575-9. [PMID: 38678087 DOI: 10.1038/s41380-024-02575-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/16/2024] [Accepted: 04/19/2024] [Indexed: 04/29/2024]
Abstract
Psilocybin has shown promise for alleviating symptoms of depression and is currently in clinical trials for the treatment of anorexia nervosa (AN), a condition that is characterised by persistent cognitive inflexibility. Considering that enhanced cognitive flexibility after psilocybin treatment is reported to occur in individuals with depression, it is plausible that psilocybin could improve symptoms of AN by breaking down cognitive inflexibility. A mechanistic understanding of the actions of psilocybin is required to tailor the clinical application of psilocybin to individuals most likely to respond with positive outcomes. This can only be achieved using incisive neurobiological approaches in animal models. Here, we use the activity-based anorexia (ABA) rat model and comprehensively assess aspects of reinforcement learning to show that psilocybin (post-acutely) improves body weight maintenance in female rats and facilitates cognitive flexibility, specifically via improved adaptation to the initial reversal of reward contingencies. Further, we reveal the involvement of signalling through the serotonin (5-HT) 1 A and 5-HT2A receptor subtypes in specific aspects of learning, demonstrating that 5-HT1A antagonism negates the cognitive enhancing effects of psilocybin. Moreover, we show that psilocybin elicits a transient increase and decrease in cortical transcription of these receptors (Htr2a and Htr1a, respectively), and a further reduction in the abundance of Htr2a transcripts in rats exposed to the ABA model. Together, these findings support the hypothesis that psilocybin could ameliorate cognitive inflexibility in the context of AN and highlight a need to better understand the therapeutic mechanisms independent of 5-HT2A receptor binding.
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Affiliation(s)
- K Conn
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia
| | - L K Milton
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia
| | - K Huang
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia
| | - H Munguba
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, 10065, USA
| | - J Ruuska
- University of Helsinki, Yliopistonkatu 4, 00100, Helsinki, Finland
| | - M B Lemus
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia
| | - E Greaves
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia
| | - J Homman-Ludiye
- Monash Micro Imaging, Monash University, 15 Innovation Walk, Clayton, VIC, 3800, Australia
| | - B J Oldfield
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia
| | - C J Foldi
- Monash University, Department of Physiology, 26 Innovation Walk, Clayton, VIC, 3800, Australia.
- Monash Biomedicine Discovery Institute, 23 Innovation Walk, Clayton, VIC, 3800, Australia.
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Allen J, Dames SS, Foldi CJ, Shultz SR. Psychedelics for acquired brain injury: a review of molecular mechanisms and therapeutic potential. Mol Psychiatry 2024:10.1038/s41380-023-02360-0. [PMID: 38177350 DOI: 10.1038/s41380-023-02360-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 11/24/2023] [Accepted: 12/01/2023] [Indexed: 01/06/2024]
Abstract
Acquired brain injury (ABI), such as traumatic brain injury and stroke, is a leading cause of disability worldwide, resulting in debilitating acute and chronic symptoms, as well as an increased risk of developing neurological and neurodegenerative disorders. These symptoms can stem from various neurophysiological insults, including neuroinflammation, oxidative stress, imbalances in neurotransmission, and impaired neuroplasticity. Despite advancements in medical technology and treatment interventions, managing ABI remains a significant challenge. Emerging evidence suggests that psychedelics may rapidly improve neurobehavioral outcomes in patients with various disorders that share physiological similarities with ABI. However, research specifically focussed on psychedelics for ABI is limited. This narrative literature review explores the neurochemical properties of psychedelics as a therapeutic intervention for ABI, with a focus on serotonin receptors, sigma-1 receptors, and neurotrophic signalling associated with neuroprotection, neuroplasticity, and neuroinflammation. The promotion of neuronal growth, cell survival, and anti-inflammatory properties exhibited by psychedelics strongly supports their potential benefit in managing ABI. Further research and translational efforts are required to elucidate their therapeutic mechanisms of action and to evaluate their effectiveness in treating the acute and chronic phases of ABI.
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Affiliation(s)
- Josh Allen
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Shannon S Dames
- Psychedelic-Assisted Therapy Post-Graduate Program, Health Sciences and Human Services, Vancouver Island University, Nanaimo, BC, Canada
| | - Claire J Foldi
- Department of Physiology, Monash University, Clayton, VIC, Australia
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Sandy R Shultz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.
- Centre for Trauma and Mental Health Research, Health Sciences and Human Services, Vancouver Island University, Nanaimo, BC, Canada.
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