1
|
Abstract
Psilocybin is a naturally occurring psychedelic compound with profound perception-, emotion- and cognition-altering properties and great potential for treating brain disorders. However, the neural mechanisms mediating its effects require in-depth investigation as there is still much to learn about how psychedelic drugs produce their profound and long-lasting effects. In this review, we outline the current understanding of the neurophysiology of psilocybin's psychoactive properties, highlighting the need for additional preclinical studies to determine its effect on neural network dynamics. We first describe how psilocybin's effect on brain regions associated with the default-mode network (DMN), particularly the prefrontal cortex and hippocampus, likely plays a key role in mediating its consciousness-altering properties. We then outline the specific receptor and cell types involved and discuss contradictory evidence from neuroimaging studies regarding psilocybin's net effect on activity within these regions. We go on to argue that in vivo electrophysiology is ideally suited to provide a more holistic, neural network analysis approach to understand psilocybin's mode of action. Thus, we integrate information about the neural bases for oscillatory activity generation with the accumulating evidence about psychedelic drug effects on neural synchrony within DMN-associated areas. This approach will help to generate important questions for future preclinical and clinical studies. Answers to these questions are vital for determining the neural mechanisms mediating psilocybin's psychotherapeutic potential, which promises to improve outcomes for patients with severe depression and other difficulty to treat conditions.
Collapse
Affiliation(s)
- Rebecca Smausz
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK
| | - Joanna Neill
- Division of Pharmacy and
Optometry, Faculty of Biology, Medicine and Health, The University of
Manchester, Manchester, UK,Medical Psychedelics Working
Group, Drug Science, UK
| | - John Gigg
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK,John Gigg, Division of Neuroscience
and Experimental Psychology, Faculty of Biology, Medicine and Health,
The University of Manchester, Manchester, M13 9PT, UK.
| |
Collapse
|
2
|
Pauwelyn G, Vlerick L, Dockx R, Verhoeven J, Dobbeleir A, Bosmans T, Peremans K, Vanhove C, Polis I, De Vos F. Kinetic analysis of [ 18F] altanserin bolus injection in the canine brain using PET imaging. BMC Vet Res 2019; 15:415. [PMID: 31752848 PMCID: PMC6873736 DOI: 10.1186/s12917-019-2165-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Currently, [18F] altanserin is the most frequently used PET-radioligand for serotonin2A (5-HT2A) receptor imaging in the human brain but has never been validated in dogs. In vivo imaging of this receptor in the canine brain could improve diagnosis and therapy of several behavioural disorders in dogs. Furthermore, since dogs are considered as a valuable animal model for human psychiatric disorders, the ability to image this receptor in dogs could help to increase our understanding of the pathophysiology of these diseases. Therefore, five healthy laboratory beagles underwent a 90-min dynamic PET scan with arterial blood sampling after [18F] altanserin bolus injection. Compartmental modelling using metabolite corrected arterial input functions was compared with reference tissue modelling with the cerebellum as reference region. RESULTS The distribution of [18F] altanserin in the canine brain corresponded well to the distribution of 5-HT2A receptors in human and rodent studies. The kinetics could be best described by a 2-Tissue compartment (2-TC) model. All reference tissue models were highly correlated with the 2-TC model, indicating compartmental modelling can be replaced by reference tissue models to avoid arterial blood sampling. CONCLUSIONS This study demonstrates that [18F] altanserin PET is a reliable tool to visualize and quantify the 5-HT2A receptor in the canine brain.
Collapse
Affiliation(s)
- Glenn Pauwelyn
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium.
| | - Lise Vlerick
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Robrecht Dockx
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.,Department of Psychiatry and Medical Psychology, Ghent University, Ghent, Belgium
| | - Jeroen Verhoeven
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| | - Andre Dobbeleir
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.,Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
| | - Tim Bosmans
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Kathelijne Peremans
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Christian Vanhove
- Institute Biomedical Technology - Medisip - Infinity, Ghent University, Ghent, Belgium
| | - Ingeborgh Polis
- Small animal Departments, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Filip De Vos
- Laboratory of Radiopharmacy, Ghent University, Ottergemsesteenweg 460, 9000, Ghent, Belgium
| |
Collapse
|