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Yang L, Fang F, Wang WX, Xie Y, Cang J, Li SB. Substantia Innominata Glutamatergic Neurons Modulate Sevoflurane Anesthesia in Male Mice. Anesth Analg 2024:00000539-990000000-00862. [PMID: 39008422 DOI: 10.1213/ane.0000000000007092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
BACKGROUND Accumulated evidence suggests that brain regions that promote wakefulness also facilitate emergence from general anesthesia (GA). Glutamatergic neurons in the substantia innominata (SI) regulate motivation-related aversive, depressive, and aggressive behaviors relying on heightened arousal. Here, we hypothesize that glutamatergic neurons in the SI are also involved in the regulation of the effects of sevoflurane anesthesia. METHODS With a combination of fiber photometry, chemogenetic and optogenetic tools, behavioral tests, and cortical electroencephalogram recordings, we investigated whether and how SI glutamatergic neurons and their projections to the lateral hypothalamus (LH) regulate sevoflurane anesthesia in adult male mice. RESULTS Population activity of glutamatergic neurons in the SI gradually decreased upon sevoflurane-induced loss of consciousness (LOC) and slowly returned as soon as inhalation of sevoflurane discontinued before recovery of consciousness (ROC). Chemogenetic activation of SI glutamatergic neurons dampened the animals' sensitivity to sevoflurane exposure, prolonged induction time (mean ± standard deviation [SD]; 389 ± 67 seconds vs 458 ± 53 seconds; P = .047), and shortened emergence time (305 seconds, 95% confidence interval [CI], 242-369 seconds vs 207 seconds, 95% CI, 135-279 seconds; P = .004), whereas chemogenetic inhibition of these neurons facilitated sevoflurane anesthesia. Furthermore, optogenetic activation of SI glutamatergic neurons and their terminals in LH induced cortical activation and behavioral emergence from different depths of sevoflurane anesthesia. CONCLUSIONS Our study shows that SI glutamatergic neuronal activity facilitates emergence from sevoflurane anesthesia and provides evidence for the involvement of the SI-LH glutamatergic pathway in the regulation of consciousness during GA.
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Affiliation(s)
- Li Yang
- From the Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Fang Fang
- From the Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wen-Xu Wang
- Institute for Translational Brain Research, State Key Laboratory of Medical Neurobiology, Frontiers Center for Brain Science of the Ministry of Education (MOE), Fudan University, Shanghai, China
| | - Yunli Xie
- Department of Anesthesiology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China and
| | - Jing Cang
- From the Department of Anesthesiology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Shi-Bin Li
- Department of Anesthesiology, Zhongshan Hospital, Institute for Translational Brain Research, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, MOE Innovative Center for New Drug Development of Immune Inflammatory Diseases, Fudan University, Shanghai, China
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Bennett C, Ouellette B, Ramirez TK, Cahoon A, Cabasco H, Browning Y, Lakunina A, Lynch GF, McBride EG, Belski H, Gillis R, Grasso C, Howard R, Johnson T, Loeffler H, Smith H, Sullivan D, Williford A, Caldejon S, Durand S, Gale S, Guthrie A, Ha V, Han W, Hardcastle B, Mochizuki C, Sridhar A, Suarez L, Swapp J, Wilkes J, Siegle JH, Farrell C, Groblewski PA, Olsen SR. SHIELD: Skull-shaped hemispheric implants enabling large-scale electrophysiology datasets in the mouse brain. Neuron 2024:S0896-6273(24)00450-1. [PMID: 38996587 DOI: 10.1016/j.neuron.2024.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 05/02/2024] [Accepted: 06/18/2024] [Indexed: 07/14/2024]
Abstract
To understand the neural basis of behavior, it is essential to measure spiking dynamics across many interacting brain regions. Although new technologies, such as Neuropixels probes, facilitate multi-regional recordings, significant surgical and procedural hurdles remain for these experiments to achieve their full potential. Here, we describe skull-shaped hemispheric implants enabling large-scale electrophysiology datasets (SHIELD). These 3D-printed skull-replacement implants feature customizable insertion holes, allowing dozens of cortical and subcortical structures to be recorded in a single mouse using repeated multi-probe insertions over many days. We demonstrate the procedure's high success rate, biocompatibility, lack of adverse effects on behavior, and compatibility with imaging and optogenetics. To showcase SHIELD's scientific utility, we use multi-probe recordings to reveal novel insights into how alpha rhythms organize spiking activity across visual and sensorimotor networks. Overall, this method enables powerful, large-scale electrophysiological experiments for the study of distributed neural computation.
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Affiliation(s)
- Corbett Bennett
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA.
| | - Ben Ouellette
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | | | | | - Hannah Cabasco
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Yoni Browning
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Anna Lakunina
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Galen F Lynch
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | | | - Hannah Belski
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Ryan Gillis
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Conor Grasso
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Robert Howard
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Tye Johnson
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Henry Loeffler
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Heston Smith
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | | | | | | | | | - Samuel Gale
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Alan Guthrie
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Vivian Ha
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Warren Han
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Ben Hardcastle
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | | | - Arjun Sridhar
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Lucas Suarez
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Jackie Swapp
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | - Joshua Wilkes
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA
| | | | | | | | - Shawn R Olsen
- Allen Institute for Neural Dynamics, Seattle, WA 98109, USA.
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Fettiplace MR, Vincent KF, Cho A, Dillon E, Stapley BM, Stewart V, Solt K. Dopaminergic psychostimulants cause arousal from isoflurane-induced sedation without reversing memory impairment in rats. Br J Anaesth 2024:S0007-0912(24)00336-2. [PMID: 38965013 DOI: 10.1016/j.bja.2024.05.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/30/2024] [Accepted: 05/04/2024] [Indexed: 07/06/2024] Open
Abstract
BACKGROUND Dopaminergic psychostimulants can restore arousal in anaesthetised animals, and dopaminergic signalling contributes to hippocampal-dependent memory formation. We tested the hypothesis that dopaminergic psychostimulants can antagonise the amnestic effects of isoflurane on visuospatial working memory. METHODS Sixteen adult Sprague-Dawley rats were trained on a trial-unique nonmatching-to-location (TUNL) task which assessed the ability to identify a novel touchscreen location after a fixed delay. Once trained, the effects of low-dose isoflurane (0.3 vol%) on task performance and activity, assessed by infrared beam breaks, were assessed. We attempted to rescue deficits in performance and activity with a dopamine D1 receptor agonist (chloro-APB), a noradrenergic reuptake inhibitor (atomoxetine), and a mixed dopamine/norepinephrine releasing agent (dextroamphetamine). Anaesthetic induction, emergence, and recovery from anaesthesia were also investigated. RESULTS Low-dose isoflurane impaired working memory in a sex-independent and intra-trial delay-independent manner as assessed by task performance, and caused an overall reduction in activity. Administration of chloro-APB, atomoxetine, or dextroamphetamine did not restore visuospatial working memory, but chloro-APB and dextroamphetamine recovered arousal to levels observed in the baseline awake state. Performance did not differ between induction and emergence. Animals recovered to baseline performance within 15 min of discontinuing isoflurane. CONCLUSIONS Low-dose isoflurane impairs visuospatial working memory in a nondurable and delay-independent manner that potentially implicates non-hippocampal structures in isoflurane-induced memory deficits. Dopaminergic psychostimulants counteracted sedation but did not reverse memory impairments, suggesting that isoflurane-induced amnesia and isoflurane-induced sedation have distinct underlying mechanisms that can be antagonised independently.
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Affiliation(s)
- Michael R Fettiplace
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA.
| | - Kathleen F Vincent
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
| | - Angel Cho
- Touro College of Osteopathic Medicine, New York, NY, USA
| | - Emmaline Dillon
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, USA
| | - Brendan M Stapley
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, USA
| | - Victoria Stewart
- University of California Irvine School of Medicine, Irvine, CA, USA
| | - Ken Solt
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
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Silverstein BH, Parkar A, Groenhout T, Fracz Z, Fryzel AM, Fields CW, Nelson A, Liu T, Vanini G, Mashour GA, Pal D. Effect of prolonged sedation with dexmedetomidine, midazolam, propofol, and sevoflurane on sleep homeostasis in rats. Br J Anaesth 2024; 132:1248-1259. [PMID: 38071152 DOI: 10.1016/j.bja.2023.11.014] [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: 05/08/2023] [Revised: 10/23/2023] [Accepted: 11/01/2023] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Sleep disruption is a common occurrence during medical care and is detrimental to patient recovery. Long-term sedation in the critical care setting is a modifiable factor that affects sleep, but the impact of different sedative-hypnotics on sleep homeostasis is not clear. METHODS We conducted a systematic comparison of the effects of prolonged sedation (8 h) with i.v. and inhalational agents on sleep homeostasis. Adult Sprague-Dawley rats (n=10) received dexmedetomidine or midazolam on separate days. Another group (n=9) received propofol or sevoflurane on separate days. A third group (n=12) received coadministration of dexmedetomidine and sevoflurane. Wakefulness (wake), slow-wave sleep (SWS), and rapid eye movement (REM) sleep were quantified during the 48-h post-sedation period, during which we also assessed wake-associated neural dynamics using two electroencephalographic measures: theta-high gamma phase-amplitude coupling and high gamma weighted phase-lag index. RESULTS Dexmedetomidine-, midazolam-, or propofol-induced sedation increased wake and decreased SWS and REM sleep (P<0.0001) during the 48-h post-sedation period. Sevoflurane produced no change in SWS, decreased wake for 3 h, and increased REM sleep for 6 h (P<0.02) post-sedation. Coadministration of dexmedetomidine and sevoflurane induced no change in wake (P>0.05), increased SWS for 3 h, and decreased REM sleep for 9 h (P<0.02) post-sedation. Dexmedetomidine, midazolam, and coadministration of dexmedetomidine with sevoflurane reduced wake-associated phase-amplitude coupling (P≤0.01). All sedatives except sevoflurane decreased wake-associated high gamma weighted phase-lag index (P<0.01). CONCLUSIONS In contrast to i.v. drugs, prolonged sevoflurane sedation produced minimal changes in sleep homeostasis and neural dynamics. Further studies are warranted to assess inhalational agents for long-term sedation and sleep homeostasis.
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Affiliation(s)
- Brian H Silverstein
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA
| | - Anjum Parkar
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Trent Groenhout
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Zuzanna Fracz
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Anna M Fryzel
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | | | - Amanda Nelson
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Tiecheng Liu
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA; Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.
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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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Mashour GA. Ketamine and the paradox of anaesthetic state transitions. Br J Anaesth 2024; 132:224-226. [PMID: 38092601 DOI: 10.1016/j.bja.2023.11.030] [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: 11/05/2023] [Accepted: 11/22/2023] [Indexed: 01/21/2024] Open
Abstract
Administration of subanaesthetic doses of ketamine during isoflurane anaesthesia has been shown in animals to deepen the anaesthetised state, while accelerating emergence. Duan and colleagues have now shown that the addition of subanaesthetic doses of esketamine to isoflurane has a similar effect of increasing the burst suppression ratio, while accelerating emergence. Using c-Fos expression and fibre photometry, they show that esketamine activates glutamatergic neurones in the paraventricular nucleus of the thalamus, a structure that regulates wakefulness. Chemogenetic inhibition of these neurones attenuates the arousal-promoting effects, suggesting a causal role of the paraventricular nucleus of the thalamus in esketamine-mediated acceleration of recovery from anaesthesia.
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Affiliation(s)
- George A Mashour
- Department of Anesthesiology, Department of Pharmacology, Center for Consciousness Science, Michigan Psychedelic Center, University of Michigan Medical School, Ann Arbor, MI, USA.
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Wasilczuk AZ, Rinehart C, Aggarwal A, Stone ME, Mashour GA, Avidan MS, Kelz MB, Proekt A. Hormonal basis of sex differences in anesthetic sensitivity. Proc Natl Acad Sci U S A 2024; 121:e2312913120. [PMID: 38190526 PMCID: PMC10801881 DOI: 10.1073/pnas.2312913120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 11/20/2023] [Indexed: 01/10/2024] Open
Abstract
General anesthesia-a pharmacologically induced reversible state of unconsciousness-enables millions of life-saving procedures. Anesthetics induce unconsciousness in part by impinging upon sexually dimorphic and hormonally sensitive hypothalamic circuits regulating sleep and wakefulness. Thus, we hypothesized that anesthetic sensitivity should be sex-dependent and modulated by sex hormones. Using distinct behavioral measures, we show that at identical brain anesthetic concentrations, female mice are more resistant to volatile anesthetics than males. Anesthetic sensitivity is bidirectionally modulated by testosterone. Castration increases anesthetic resistance. Conversely, testosterone administration acutely increases anesthetic sensitivity. Conversion of testosterone to estradiol by aromatase is partially responsible for this effect. In contrast, oophorectomy has no effect. To identify the neuronal circuits underlying sex differences, we performed whole brain c-Fos activity mapping under anesthesia in male and female mice. Consistent with a key role of the hypothalamus, we found fewer active neurons in the ventral hypothalamic sleep-promoting regions in females than in males. In humans, we demonstrate that females regain consciousness and recover cognition faster than males after identical anesthetic exposures. Remarkably, while behavioral and neurocognitive measures in mice and humans point to increased anesthetic resistance in females, cortical activity fails to show sex differences under anesthesia in either species. Cumulatively, we demonstrate that sex differences in anesthetic sensitivity are evolutionarily conserved and not reflected in conventional electroencephalographic-based measures of anesthetic depth. This covert resistance to anesthesia may explain the higher incidence of unintended awareness under general anesthesia in females.
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Affiliation(s)
- Andrzej Z. Wasilczuk
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Neuroscience of Unconsciousness and Reanimation Research Alliance, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA19104
| | - Cole Rinehart
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Neuroscience of Unconsciousness and Reanimation Research Alliance, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
| | - Adeeti Aggarwal
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Neuroscience of Unconsciousness and Reanimation Research Alliance, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA19104
| | - Martha E. Stone
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Neuroscience of Unconsciousness and Reanimation Research Alliance, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA19104
| | - George A. Mashour
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI48105
| | - Michael S. Avidan
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO63110
| | - Max B. Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Neuroscience of Unconsciousness and Reanimation Research Alliance, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA19104
- Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - Alex Proekt
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Neuroscience of Unconsciousness and Reanimation Research Alliance, Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA19104
- Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA19104
| | - ReCCognition Study Group
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Philadelphia, PA19104
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI48105
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO63110
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Vincent KF, Mallari OG, Dillon EJ, Stewart VG, Cho AJ, Dong Y, Edlow AG, Ichinose F, Xie Z, Solt K. Oestrous cycle affects emergence from anaesthesia with dexmedetomidine, but not propofol, isoflurane, or sevoflurane, in female rats. Br J Anaesth 2023; 131:67-78. [PMID: 37142466 PMCID: PMC10308440 DOI: 10.1016/j.bja.2023.03.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/17/2023] [Accepted: 03/13/2023] [Indexed: 05/06/2023] Open
Abstract
BACKGROUND Although sex differences in anaesthetic sensitivity have been reported, what underlies these differences is unknown. In rodents, one source of variability in females is the oestrous cycle. Here we test the hypothesis that the oestrous cycle impacts emergence from general anaesthesia. METHODS Time to emergence was measured after isoflurane (2 vol% for 1 h), sevoflurane (3 vol% for 20 min), dexmedetomidine (50 μg kg-1 i.v., infused over 10 min), or propofol (10 mg kg-1 i.v. bolus) during proestrus, oestrus, early dioestrus, and late dioestrus in female Sprague-Dawley rats (n=24). EEG recordings were taken during each test for power spectral analysis. Serum was analysed for 17β-oestradiol and progesterone concentrations. The effect of oestrous cycle stage on return of righting latency was assessed using a mixed model. The association between righting latency and serum hormone concentration was tested by linear regression. Mean arterial blood pressure and arterial blood gases were assessed in a subset of rats after dexmedetomidine and compared in a mixed model. RESULTS Oestrous cycle did not affect righting latency after isoflurane, sevoflurane, or propofol. When in the early dioestrus stage, rats emerged more rapidly from dexmedetomidine than in the proestrus (P=0.0042) or late dioestrus (P=0.0230) stage and showed reduced overall power in frontal EEG spectra 30 min after dexmedetomidine (P=0.0049). 17β-Oestradiol and progesterone serum concentrations did not correlate with righting latency. Oestrous cycle did not affect mean arterial blood pressure or blood gases during dexmedetomidine. CONCLUSIONS In female rats, the oestrous cycle significantly impacts emergence from dexmedetomidine-induced unconsciousness. However, 17β-oestradiol and progesterone serum concentrations do not correlate with the observed changes.
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Affiliation(s)
- Kathleen F Vincent
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
| | - Olivia G Mallari
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anesthesiology, Columbia University, New York, NY, USA
| | - Emmaline J Dillon
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Brigham Young University, Provo, UT, USA
| | - Victoria G Stewart
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Brigham Young University, Provo, UT, USA
| | - Angel J Cho
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Touro College of Osteopathic Medicine, New York, NY, USA
| | - Yuanlin Dong
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
| | - Andrea G Edlow
- Obstetrics and Gynecology, Massachusetts General Hospital, Boston, MA, USA; Department of Obstetrics, Gynecology, and Reproductive Biology, Harvard Medical School, Boston, MA, USA
| | - Fumito Ichinose
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
| | - Zhongcong Xie
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA
| | - Ken Solt
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA; Department of Anaesthesia, Harvard Medical School, Boston, MA, USA.
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