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Hines AD, Kewin AB, Van De Poll MN, Anggono V, Bademosi AT, van Swinderen B. Synapse-Specific Trapping of SNARE Machinery Proteins in the Anesthetized Drosophila Brain. J Neurosci 2024; 44:e0588232024. [PMID: 38749704 PMCID: PMC11170680 DOI: 10.1523/jneurosci.0588-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/01/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024] Open
Abstract
General anesthetics disrupt brain network dynamics through multiple pathways, in part through postsynaptic potentiation of inhibitory ion channels as well as presynaptic inhibition of neuroexocytosis. Common clinical general anesthetic drugs, such as propofol and isoflurane, have been shown to interact and interfere with core components of the exocytic release machinery to cause impaired neurotransmitter release. Recent studies however suggest that these drugs do not affect all synapse subtypes equally. We investigated the role of the presynaptic release machinery in multiple neurotransmitter systems under isoflurane general anesthesia in the adult female Drosophila brain using live-cell super-resolution microscopy and optogenetic readouts of exocytosis and neural excitability. We activated neurotransmitter-specific mushroom body output neurons and imaged presynaptic function under isoflurane anesthesia. We found that isoflurane impaired synaptic release and presynaptic protein dynamics in excitatory cholinergic synapses. In contrast, isoflurane had little to no effect on inhibitory GABAergic or glutamatergic synapses. These results present a distinct inhibitory mechanism for general anesthesia, whereby neuroexocytosis is selectively impaired at excitatory synapses, while inhibitory synapses remain functional. This suggests a presynaptic inhibitory mechanism that complements the other inhibitory effects of these drugs.
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Affiliation(s)
- Adam D Hines
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Amber B Kewin
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Matthew N Van De Poll
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Victor Anggono
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
- Clem Jones Centre for Ageing and Dementia Research, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Adekunle T Bademosi
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
- Clem Jones Centre for Ageing and Dementia Research, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
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Cylinder DM, van Zundert AA, Solt K, van Swinderen B. Time to Wake Up! The Ongoing Search for General Anesthetic Reversal Agents. Anesthesiology 2024; 140:610-627. [PMID: 38349760 PMCID: PMC10868874 DOI: 10.1097/aln.0000000000004846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
How general anesthetics work remains a topic of ongoing study. A parallel field of research has sought to identify methods to reverse general anesthesia. Reversal agents could shorten patients' recovery time and potentially reduce the risk of postoperative complications. An incomplete understanding of the mechanisms of general anesthesia has hampered the pursuit for reversal agents. Nevertheless, the search for reversal agents has furthered understanding of the mechanisms underlying general anesthesia. The study of potential reversal agents has highlighted the importance of rigorous criteria to assess recovery from general anesthesia in animal models, and has helped identify key arousal systems (e.g., cholinergic, dopaminergic, and orexinergic systems) relevant to emergence from general anesthesia. Furthermore, the effects of reversal agents have been found to be inconsistent across different general anesthetics, revealing differences in mechanisms among these drugs. The presynapse and glia probably also contribute to general anesthesia recovery alongside postsynaptic receptors. The next stage in the search for reversal agents will have to consider alternate mechanisms encompassing the tripartite synapse.
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Affiliation(s)
- Drew M. Cylinder
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - André A.J. van Zundert
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Department of Anaesthesia and Perioperative Medicine, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
| | - Ken Solt
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, U.S.A
- Department of Anaesthesia, Harvard Medical School, Boston, MA, U.S.A
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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Jagannathan SR, Jeans T, Van De Poll MN, van Swinderen B. Multivariate classification of multichannel long-term electrophysiology data identifies different sleep stages in fruit flies. SCIENCE ADVANCES 2024; 10:eadj4399. [PMID: 38381836 PMCID: PMC10881036 DOI: 10.1126/sciadv.adj4399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 01/18/2024] [Indexed: 02/23/2024]
Abstract
Identifying different sleep stages in humans and other mammals has traditionally relied on electroencephalograms. Such an approach is not feasible in certain animals such as invertebrates, although these animals could also be sleeping in stages. Here, we perform long-term multichannel local field potential recordings in the brains of behaving flies undergoing spontaneous sleep bouts. We acquired consistent spatial recordings of local field potentials across multiple flies, allowing us to compare brain activity across awake and sleep periods. Using machine learning, we uncover distinct temporal stages of sleep and explore the associated spatial and spectral features across the fly brain. Further, we analyze the electrophysiological correlates of microbehaviors associated with certain sleep stages. We confirm the existence of a distinct sleep stage associated with rhythmic proboscis extensions and show that spectral features of this sleep-related behavior differ significantly from those associated with the same behavior during wakefulness, indicating a dissociation between behavior and the brain states wherein these behaviors reside.
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Affiliation(s)
- Sridhar R. Jagannathan
- Department of Psychology, University of Cambridge, Cambridge, UK
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Travis Jeans
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD Australia
| | | | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St Lucia, QLD Australia
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Anthoney N, Tainton-Heap L, Luong H, Notaras E, Kewin AB, Zhao Q, Perry T, Batterham P, Shaw PJ, van Swinderen B. Experimentally induced active and quiet sleep engage non-overlapping transcriptional programs in Drosophila. eLife 2023; 12:RP88198. [PMID: 37910019 PMCID: PMC10619980 DOI: 10.7554/elife.88198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023] Open
Abstract
Sleep in mammals can be broadly classified into two different physiological categories: rapid eye movement (REM) sleep and slow-wave sleep (SWS), and accordingly REM and SWS are thought to achieve a different set of functions. The fruit fly Drosophila melanogaster is increasingly being used as a model to understand sleep functions, although it remains unclear if the fly brain also engages in different kinds of sleep as well. Here, we compare two commonly used approaches for studying sleep experimentally in Drosophila: optogenetic activation of sleep-promoting neurons and provision of a sleep-promoting drug, gaboxadol. We find that these different sleep-induction methods have similar effects on increasing sleep duration, but divergent effects on brain activity. Transcriptomic analysis reveals that drug-induced deep sleep ('quiet' sleep) mostly downregulates metabolism genes, whereas optogenetic 'active' sleep upregulates a wide range of genes relevant to normal waking functions. This suggests that optogenetics and pharmacological induction of sleep in Drosophila promote different features of sleep, which engage different sets of genes to achieve their respective functions.
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Affiliation(s)
- Niki Anthoney
- Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Lucy Tainton-Heap
- Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Hang Luong
- School of BioSciences, The University of MelbourneMelbourneAustralia
| | - Eleni Notaras
- Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Amber B Kewin
- Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Qiongyi Zhao
- Queensland Brain Institute, The University of QueenslandBrisbaneAustralia
| | - Trent Perry
- School of BioSciences, The University of MelbourneMelbourneAustralia
| | - Philip Batterham
- School of BioSciences, The University of MelbourneMelbourneAustralia
| | - Paul J Shaw
- Department of Neuroscience, School of Medicine, Washington University in St. LouisSt LouisUnited States
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Anthoney N, Tainton-Heap LA, Luong H, Notaras E, Kewin AB, Zhao Q, Perry T, Batterham P, Shaw PJ, van Swinderen B. Experimentally induced active and quiet sleep engage non-overlapping transcriptional programs in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.03.535331. [PMID: 37066182 PMCID: PMC10103959 DOI: 10.1101/2023.04.03.535331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Sleep in mammals can be broadly classified into two different physiological categories: rapid eye movement (REM) sleep and slow wave sleep (SWS), and accordingly REM and SWS are thought to achieve a different set of functions. The fruit fly Drosophila melanogaster is increasingly being used as a model to understand sleep functions, although it remains unclear if the fly brain also engages in different kinds of sleep as well. Here, we compare two commonly used approaches for studying sleep experimentally in Drosophila: optogenetic activation of sleep-promoting neurons and provision of a sleep-promoting drug, Gaboxadol. We find that these different sleep-induction methods have similar effects on increasing sleep duration, but divergent effects on brain activity. Transcriptomic analysis reveals that drug-induced deep sleep ('quiet' sleep) mostly downregulates metabolism genes, whereas optogenetic 'active' sleep upregulates a wide range of genes relevant to normal waking functions. This suggests that optogenetics and pharmacological induction of sleep in Drosophila promote different features of sleep, which engage different sets of genes to achieve their respective functions.
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Affiliation(s)
- Niki Anthoney
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072 Australia
| | | | - Hang Luong
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3052 Australia
| | - Eleni Notaras
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Amber B. Kewin
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Qiongyi Zhao
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072 Australia
| | - Trent Perry
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3052 Australia
| | - Philip Batterham
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3052 Australia
| | - Paul J. Shaw
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO USA
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072 Australia
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Jagannathan SR, Jeans R, Van De Poll MN, van Swinderen B. Multivariate classification of multichannel long-term electrophysiology data identifies different sleep stages in fruit flies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.544704. [PMID: 37398087 PMCID: PMC10312633 DOI: 10.1101/2023.06.12.544704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Sleep is observed in most animals, which suggests it subserves a fundamental process associated with adaptive biological functions. However, the evidence to directly associate sleep with a specific function is lacking, in part because sleep is not a single process in many animals. In humans and other mammals, different sleep stages have traditionally been identified using electroencephalograms (EEGs), but such an approach is not feasible in different animals such as insects. Here, we perform long-term multichannel local field potential (LFP) recordings in the brains of behaving flies undergoing spontaneous sleep bouts. We developed protocols to allow for consistent spatial recordings of LFPs across multiple flies, allowing us to compare the LFP activity across awake and sleep periods and further compare the same to induced sleep. Using machine learning, we uncover the existence of distinct temporal stages of sleep and explore the associated spatial and spectral features across the fly brain. Further, we analyze the electrophysiological correlates of micro-behaviours associated with certain sleep stages. We confirm the existence of a distinct sleep stage associated with rhythmic proboscis extensions and show that spectral features of this sleep-related behavior differ significantly from those associated with the same behavior during wakefulness, indicating a dissociation between behavior and the brain states wherein these behaviors reside.
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Affiliation(s)
- Sridhar R. Jagannathan
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
- Institute of Neurophysiology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Rhiannon Jeans
- Queensland Brain Institute, The University of Queensland, St Lucia, Australia
| | | | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St Lucia, Australia
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