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Benoit E, Lyons DG, Rihel J. Noradrenergic tone is not required for neuronal activity-induced rebound sleep in zebrafish. J Comp Physiol B 2024; 194:279-298. [PMID: 37480493 PMCID: PMC11233345 DOI: 10.1007/s00360-023-01504-6] [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: 03/20/2023] [Accepted: 07/03/2023] [Indexed: 07/24/2023]
Abstract
Sleep pressure builds during wakefulness, but the mechanisms underlying this homeostatic process are poorly understood. One zebrafish model suggests that sleep pressure increases as a function of global neuronal activity, such as during sleep deprivation or acute exposure to drugs that induce widespread brain activation. Given that the arousal-promoting noradrenergic system is important for maintaining heightened neuronal activity during wakefulness, we hypothesised that genetic and pharmacological reduction of noradrenergic tone during drug-induced neuronal activation would dampen subsequent rebound sleep in zebrafish larvae. During stimulant drug treatment, dampening noradrenergic tone with the α2-adrenoceptor agonist clonidine unexpectedly enhanced subsequent rebound sleep, whereas enhancing noradrenergic signalling with a cocktail of α1- and β-adrenoceptor agonists did not enhance rebound sleep. Similarly, CRISPR/Cas9-mediated elimination of the dopamine β-hydroxylase (dbh) gene, which encodes an enzyme required for noradrenalin synthesis, enhanced baseline sleep in larvae but did not prevent additional rebound sleep following acute induction of neuronal activity. Across all drug conditions, c-fos expression immediately after drug exposure correlated strongly with the amount of induced rebound sleep, but was inversely related to the strength of noradrenergic modulatory tone. These results are consistent with a model in which increases in neuronal activity, as reflected by brain-wide levels of c-fos induction, drive a sleep pressure signal that promotes rebound sleep independently of noradrenergic tone.
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Affiliation(s)
- Eleanor Benoit
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Declan G Lyons
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Jason Rihel
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK.
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Han X, Yang ZF, Zhao TY, Lu GY, Wang ZY, Wu N, Li J, Li F. Regulation of I1-imidazoline receptors on the sedation effect of dexmedetomidine in mice. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024:10.1007/s00210-024-02991-2. [PMID: 38363351 DOI: 10.1007/s00210-024-02991-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/29/2024] [Indexed: 02/17/2024]
Abstract
Dexmedetomidine has been used as a sedative drug in the clinic for a long time. Many studies demonstrated that the sedative mechanism of dexmedetomidine might be related to the activation of α2-adrenoceptor (α2AR). In addition, it was reported that dexmedetomidine had some affinity for the I1-imidazoline receptor (I1R); however, the role of I1R in dexmedetomidine-induced sedative effects and its possible mechanism are poorly studied. In the present study, we found that agmatine, an I1R agonist, was able to enhance the sedative effect of dexmedetomidine in mice. Efaroxan, an α2AR and I1R antagonist, could prevent and rescue the sedative action of dexmedetomidine in mice, and its preventive effect was better than atipamezole, the specific α2AR antagonist. Knockout of imidazoline receptor antisera-selected (IRAS), the functional I1R candidate protein, suppressed the dexmedetomidine-induced sedation. Moreover, IRAS knockout led to the inhibition of agmatine and efaroxan in regulating dexmedetomidine-induced sedative effects in mice, but not of atipamezole. We then used CHO cell lines that stably expressed α2AR and IRAS to investigate the possible molecular mechanism of IRAS in regulating the dexmedetomidine-induced sedative effect. The results showed that IRAS expression significantly up-regulated dexmedetomidine-induced ERK phosphorylation, which was enhanced by agmatine and inhibited by efaroxan at low concentrations. Therefore, by taking advantage of pharmacological and genetic approaches, our finding revealed the evidence that IRAS plays an important role in the sedative effects of dexmedetomidine, and the ERK signal pathway may be involved in the mechanism of IRAS in regulating dexmedetomidine-induced sedation. This study may offer valuable insights for the advancement of novel anesthetic adjuvants.
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Affiliation(s)
- Xiao Han
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Zhi-Fang Yang
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Tai-Yun Zhao
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Guan-Yi Lu
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Zhi-Yuan Wang
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Ning Wu
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Jin Li
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
| | - Fei Li
- Beijing Key Laboratory of Neuropsychopharmacology, State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
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Sitnikova E, Pupikina M, Rutskova E. Alpha2 Adrenergic Modulation of Spike-Wave Epilepsy: Experimental Study of Pro-Epileptic and Sedative Effects of Dexmedetomidine. Int J Mol Sci 2023; 24:ijms24119445. [PMID: 37298397 DOI: 10.3390/ijms24119445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/20/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
In the present report, we evaluated adrenergic mechanisms of generalized spike-wave epileptic discharges (SWDs), which are the encephalographic hallmarks of idiopathic generalized epilepsies. SWDs link to a hyper-synchronization in the thalamocortical neuronal activity. We unclosed some alpha2-adrenergic mechanisms of sedation and provocation of SWDs in rats with spontaneous spike-wave epilepsy (WAG/Rij and Wistar) and in control non-epileptic rats (NEW) of both sexes. Dexmedetomidine (Dex) was a highly selective alpha-2 agonist (0.003-0.049 mg/kg, i.p.). Injections of Dex did not elicit de novo SWDs in non-epileptic rats. Dex can be used to disclose the latent form of spike-wave epilepsy. Subjects with long-lasting SWDs at baseline were at high risk of absence status after activation of alpha2- adrenergic receptors. We create the concept of alpha1- and alpha2-ARs regulation of SWDs via modulation of thalamocortical network activity. Dex induced the specific abnormal state favorable for SWDs-"alpha2 wakefulness". Dex is regularly used in clinical practice. EEG examination in patients using low doses of Dex might help to diagnose the latent forms of absence epilepsy (or pathology of cortico-thalamo-cortical circuitry).
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Affiliation(s)
- Evgenia Sitnikova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, 117485 Moscow, Russia
| | - Maria Pupikina
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, 117485 Moscow, Russia
| | - Elizaveta Rutskova
- Institute of the Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Butlerova Str., 5A, 117485 Moscow, Russia
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Lawn T, Martins D, O'Daly O, Williams S, Howard M, Dipasquale O. The effects of propofol anaesthesia on molecular-enriched networks during resting-state and naturalistic listening. Neuroimage 2023; 271:120018. [PMID: 36935083 PMCID: PMC10410200 DOI: 10.1016/j.neuroimage.2023.120018] [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: 10/31/2022] [Accepted: 03/09/2023] [Indexed: 03/19/2023] Open
Abstract
Placing a patient in a state of anaesthesia is crucial for modern surgical practice. However, the mechanisms by which anaesthetic drugs, such as propofol, impart their effects on consciousness remain poorly understood. Propofol potentiates GABAergic transmission, which purportedly has direct actions on cortex as well as indirect actions via ascending neuromodulatory systems. Functional imaging studies to date have been limited in their ability to unravel how these effects on neurotransmission impact the system-level dynamics of the brain. Here, we leveraged advances in multi-modal imaging, Receptor-Enriched Analysis of functional Connectivity by Targets (REACT), to investigate how different levels of propofol-induced sedation alter neurotransmission-related functional connectivity (FC), both at rest and when individuals are exposed to naturalistic auditory stimulation. Propofol increased GABA-A- and noradrenaline transporter-enriched FC within occipital and somatosensory regions respectively. Additionally, during auditory stimulation, the network related to the dopamine transporter showed reduced FC within bilateral regions of temporal and mid/posterior cingulate cortices, with the right temporal cluster showing an interaction between auditory stimulation and level of consciousness. In bringing together these micro- and macro-scale systems, we provide support for both direct GABAergic and indirect noradrenergic and dopaminergic-related network changes under propofol sedation. Further, we delineate a cognition-related reconfiguration of the dopaminergic network, highlighting the utility of REACT to explore the molecular substrates of consciousness and cognition.
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Affiliation(s)
- Timothy Lawn
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's college London, London, UK.
| | - Daniel Martins
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's college London, London, UK
| | - Owen O'Daly
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's college London, London, UK
| | - Steve Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's college London, London, UK
| | - Matthew Howard
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's college London, London, UK
| | - Ottavia Dipasquale
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's college London, London, UK
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Yi T, Wang N, Huang J, Wang Y, Ren S, Hu Y, Xia J, Liao Y, Li X, Luo F, Ouyang Q, Li Y, Zheng Z, Xiao Q, Ren R, Yao Z, Tang X, Wang Y, Chen X, He C, Li H, Hu Z. A Sleep-Specific Midbrain Target for Sevoflurane Anesthesia. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300189. [PMID: 36961096 PMCID: PMC10214273 DOI: 10.1002/advs.202300189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/02/2023] [Indexed: 05/27/2023]
Abstract
Sevoflurane has been the most widely used inhaled anesthetics with a favorable recovery profile; however, the precise mechanisms underlying its anesthetic action are still not completely understood. Here the authors show that sevoflurane activates a cluster of urocortin 1 (UCN1+ )/cocaine- and amphetamine-regulated transcript (CART+ ) neurons in the midbrain involved in its anesthesia. Furthermore, growth hormone secretagogue receptor (GHSR) is highly enriched in sevoflurane-activated UCN1+ /CART+ cells and is necessary for sleep induction. Blockade of GHSR abolishes the excitatory effect of sevoflurane on UCN1+ /CART+ neurons and attenuates its anesthetic effect. Collectively, their data suggest that anesthetic action of sevoflurane necessitates the GHSR activation in midbrain UCN1+ /CART+ neurons, which provides a novel target including the nucleus and receptor in the field of anesthesia.
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Affiliation(s)
- Tingting Yi
- Department of AnesthesiologySecond Affiliated HospitalThird Military Medical UniversityChongqing400037China
- Department of AnesthesiologyYongchuan HospitalChongqing Medical UniversityChongqing402160China
| | - Na Wang
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
- College of BioengineeringChongqing UniversityChongqing400044China
| | - Jing Huang
- Department of AnesthesiologySecond Affiliated HospitalThird Military Medical UniversityChongqing400037China
| | - Yaling Wang
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Shuancheng Ren
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Yiwen Hu
- Department of AnesthesiologySecond Affiliated HospitalThird Military Medical UniversityChongqing400037China
| | - Jianxia Xia
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Yixiang Liao
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Xin Li
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Fenlan Luo
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Qin Ouyang
- School of PharmacyThird Military Medical UniversityChongqing400038China
| | - Yu Li
- Department of AnesthesiologySecond Affiliated HospitalThird Military Medical UniversityChongqing400037China
| | - Ziyi Zheng
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Qin Xiao
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Rong Ren
- Sleep Medicine CenterDepartment of Respiratory and Critical Care MedicineMental Health CenterWest China HospitalSichuan UniversityChengdu610041China
| | - Zhongxiang Yao
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Xiangdong Tang
- Sleep Medicine CenterDepartment of Respiratory and Critical Care MedicineMental Health CenterWest China HospitalSichuan UniversityChengdu610041China
| | - Yanjiang Wang
- Department of NeurologyDaping HospitalThird Military Medical UniversityChongqing400042China
| | - Xiaowei Chen
- Brain Research CenterCollaborative Innovation Center for Brain ScienceThird Military Medical UniversityChongqing400038China
| | - Chao He
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
| | - Hong Li
- Department of AnesthesiologySecond Affiliated HospitalThird Military Medical UniversityChongqing400037China
| | - Zhian Hu
- Department of PhysiologyThird Military Medical UniversityChongqing400038China
- College of BioengineeringChongqing UniversityChongqing400044China
- Chongqing Institute for Brain and IntelligenceGuangyang Bay LaboratoryChongqing400064China
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Alpha2-Adrenergic Receptors as a Pharmacological Target for Spike-Wave Epilepsy. Int J Mol Sci 2023; 24:ijms24021477. [PMID: 36674992 PMCID: PMC9862736 DOI: 10.3390/ijms24021477] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Spike-wave discharges are the hallmark of idiopathic generalized epilepsy. They are caused by a disorder in the thalamocortical network. Commercially available anti-epileptic drugs have pronounced side effects (i.e., sedation and gastroenterological concerns), which might result from a low selectivity to molecular targets. We suggest a specific subtype of adrenergic receptors (ARs) as a promising anti-epileptic molecular target. In rats with a predisposition to absence epilepsy, alpha2 ARs agonists provoke sedation and enhance spike-wave activity during transitions from awake/sedation. A number of studies together with our own observations bring evidence that the sedative and proepileptic effects require different alpha2 ARs subtypes activation. Here we introduce a new concept on target pharmacotherapy of absence epilepsy via alpha2B ARs which are presented almost exclusively in the thalamus. We discuss HCN and calcium channels as the most relevant cellular targets of alpha2 ARs involved in spike-wave activity generation.
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Heshmati M, Bruchas MR. Historical and Modern Evidence for the Role of Reward Circuitry in Emergence. Anesthesiology 2022; 136:997-1014. [PMID: 35362070 PMCID: PMC9467375 DOI: 10.1097/aln.0000000000004148] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Increasing evidence supports a role for brain reward circuitry in modulating arousal along with emergence from anesthesia. Emergence remains an important frontier for investigation, since no drug exists in clinical practice to initiate rapid and smooth emergence. This review discusses clinical and preclinical evidence indicating a role for two brain regions classically considered integral components of the mesolimbic brain reward circuitry, the ventral tegmental area and the nucleus accumbens, in emergence from propofol and volatile anesthesia. Then there is a description of modern systems neuroscience approaches to neural circuit investigations that will help span the large gap between preclinical and clinical investigation with the shared aim of developing therapies to promote rapid emergence without agitation or delirium. This article proposes that neuroscientists include models of whole-brain network activity in future studies to inform the translational value of preclinical investigations and foster productive dialogues with clinician anesthesiologists.
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Affiliation(s)
- Mitra Heshmati
- Center for the Neurobiology of Addiction, Pain, and Emotion, Department of Anesthesiology and Pain Medicine, and Department of Biological Structure, University of Washington, Seattle, Washington
| | - Michael R Bruchas
- Center for the Neurobiology of Addiction, Pain, and Emotion, Department of Anesthesiology and Pain Medicine, and Department of Pharmacology, University of Washington, Seattle, Washington
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A neural circuit from the paraventricular thalamus to the bed nucleus of the stria terminalis for the regulation of states of consciousness during sevoflurane anesthesia in mice. Anesthesiology 2022; 136:709-731. [PMID: 35263424 DOI: 10.1097/aln.0000000000004195] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The neural circuitry underlying sevoflurane-induced modulation of consciousness is poorly understood. We hypothesized that the paraventricular thalamus-bed nucleus of the stria terminalis pathway plays an important role in regulating states of consciousness during sevoflurane anesthesia. METHODS Rabies-virus-based transsynaptic tracing techniques were employed to reveal the neural pathway from the paraventricular thalamus to the bed nucleus of the stria terminalis. We investigated the role of this pathway in sevoflurane anesthesia induction, maintenance and emergence using chemogenetic and optogenetic methods combined with cortical electroencephalogram (EEG) recordings. Both male and female mice were used in our study. RESULTS Both GABAergic and glutamatergic neurons in the bed nucleus of the stria terminalis receive paraventricular thalamus glutamatergic projections. Chemogenetic inhibition of paraventricular thalamus glutamatergic neurons prolonged the sevoflurane anesthesia emergence time (mean ± SD, hM4D-CNO vs. mCherry-CNO, 281 ± 88 vs. 172 ± 48 s, p < 0.001, n = 24) and decreased the induction time (101 ± 32 vs. 136 ± 34 s, p = 0.002, n = 24) as well as the EC50 for the loss or recovery of the righting reflex under sevoflurane anesthesia (mean [95% confidence interval]; MACLORR, 1.16 [1.12 to 1.20] vs. 1.49 [1.46 to 1.53] vol%, p < 0.001, n = 20; MACRORR, 0.95 [0.86 to 1.03] vs. 1.34 [1.29 to 1.40] vol%, p < 0.001, n = 20). Similar results were observed during suppression of the paraventricular thalamus- bed nucleus stria terminalis pathway. Optogenetic activation of this pathway produced the opposite effects. Additionally, transient stimulation of this pathway efficiently induced behavioral arousal during continuous steady-state general anesthesia with sevoflurane and reduced the depth of anesthesia during sevoflurane-induced burst suppression. CONCLUSIONS In mice, axonal projections from the paraventricular thalamic neurons to the bed nucleus of the stria terminalis contribute to regulating states of consciousness during sevoflurane anesthesia.
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Yang Q, Zhou F, Li A, Dong H. Neural Substrates for Regulation of Sleep and General Anesthesia. Curr Neuropharmacol 2021; 20:72-84. [PMID: 34906058 PMCID: PMC9199549 DOI: 10.2174/1570159x19666211214144639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/09/2021] [Accepted: 12/10/2021] [Indexed: 11/30/2022] Open
Abstract
General anesthesia has been successfully used in clinics for over 170 years, but its mechanisms of effect remain unclear. Behaviorally, general anesthesia is similar to sleep as it produces a reversible transition between wakefulness and the state of being unaware of one’s surroundings. A discussion regarding the common circuits of sleep and general anesthesia has been ongoing as an increasing number of sleep-arousal regulatory nuclei are reported to participate in the consciousness shift occurring during general anesthesia. Recently, with progress in research technology, both positive and negative evidence for overlapping neural circuits between sleep and general anesthesia has emerged. This article provides a review of the latest evidence on the neural substrates for sleep and general anesthesia regulation by comparing the roles of pivotal nuclei in sleep and anesthesia.
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Affiliation(s)
- Qianzi Yang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an. China
| | - Fang Zhou
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an. China
| | - Ao Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an. China
| | - Hailong Dong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an. China
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Wei Y, Zhang D, Zuo Y. Metabolomics and Whole-Exome Sequencing in Patients with Differential Sensitivity to Sevoflurane: A Protocol for a Prospective Observational Trial. Front Pharmacol 2021; 12:621159. [PMID: 34790114 PMCID: PMC8591073 DOI: 10.3389/fphar.2021.621159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 10/18/2021] [Indexed: 02/05/2023] Open
Abstract
Introduction: Different sensitivity to volatile anesthetics in Drosophila, nematodes and mice is related to mutation of energy metabolism genes. In clinical practice, we find that the end-tidal sevoflurane concentration (ETsevo) differs among patients at the same depth of anesthesia, indicating that the sensitivity to sevoflurane varies among patients. However, the underlying mechanism remains unclear. The sensitivity of an anesthetic is associated with the postoperative outcomes of patients and the mechanism of action of volatile anesthetics. We therefore propose this protocol to determine whether differences in metabolite profile and genetic variations contribute to patients' sensitivity to volatile anesthetics. Methods and Analysis: This is a single-centre, prospective observational study. 720 patients undergoing abdominal surgery were included. General anesthesia was induced with inhaled sevoflurane, a bolus of sufentanil (0.2-0.4 μg/kg) and cis-atracurium (0.2-0.3 mg/kg). The end-tidal sevoflurane concentration (ETsevo) was adjusted to maintain a BIS (bispectral index) value between 40-60. The mean ETsevo from 20 min after endotracheal intubation to 2 h after the beginning of surgery (steady state) was calculated for each patient. Patients were further divided into a high-sensitivity group (mean ETsevo - SD) and a low-sensitivity group (mean ETsevo + SD) to investigate the sensitivity to sevoflurane. Cases were paired from the high-sensitivity group (group H) and low-sensitivity group (group L) according to age, sex, body mass index (BMI), ASA physical status classification, vital signs, BIS, ephedrine use, sufentanildose, and cis-atracurium dose at anesthesia induction and steady state. Differences in metabolite levels, single nucleotide polymorphisms (SNPs) and protein-coding gene sequence variations between group H and group L will be determined through plasma metabolomics, whole-exome sequencing (WES), genome-wide association study (GWAS), and bioinformatics analyses. These results will be analysed to determine the reasons for the differential sensitivity to sevoflurane in humans. Ethics and Dissemination: This prospective observational study protocol has received ethical approval from the Ethical Committee of West China Hospital of Sichuan University on May 19, 2017 (Approval No. 78). Informed consent will be obtained before patient enrolment. The results will be submitted to international peer-review journals. Trial Registration Number: ChiCTR1800014327.
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Affiliation(s)
- Yiyong Wei
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Donghang Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Yunxia Zuo
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
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11
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Excitation of Putative Glutamatergic Neurons in the Rat Parabrachial Nucleus Region Reduces Delta Power during Dexmedetomidine but not Ketamine Anesthesia. Anesthesiology 2021; 135:633-648. [PMID: 34270686 DOI: 10.1097/aln.0000000000003883] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Parabrachial nucleus excitation reduces cortical delta oscillation (0.5 to 4 Hz) power and recovery time associated with anesthetics that enhance γ-aminobutyric acid type A receptor action. The effects of parabrachial nucleus excitation on anesthetics with other molecular targets, such as dexmedetomidine and ketamine, remain unknown. The hypothesis was that parabrachial nucleus excitation would cause arousal during dexmedetomidine and ketamine anesthesia. METHODS Designer Receptors Exclusively Activated by Designer Drugs were used to excite calcium/calmodulin-dependent protein kinase 2α-positive neurons in the parabrachial nucleus region of adult male rats without anesthesia (nine rats), with dexmedetomidine (low dose: 0.3 µg · kg-1 · min-1 for 45 min, eight rats; high dose: 4.5 µg · kg-1 · min-1 for 10 min, seven rats), or with ketamine (low dose: 2 mg · kg-1 · min-1 for 30 min, seven rats; high dose: 4 mg · kg-1 · min-1 for 15 min, eight rats). For control experiments (same rats and treatments), the Designer Receptors Exclusively Activated by Designer Drugs were not excited. The electroencephalogram and anesthesia recovery times were recorded and analyzed. RESULTS Parabrachial nucleus excitation reduced delta power in the prefrontal electroencephalogram with low-dose dexmedetomidine for the 150-min analyzed period, excepting two brief periods (peak median bootstrapped difference [clozapine-N-oxide - saline] during dexmedetomidine infusion = -6.06 [99% CI = -12.36 to -1.48] dB, P = 0.007). However, parabrachial nucleus excitation was less effective at reducing delta power with high-dose dexmedetomidine and low- and high-dose ketamine (peak median bootstrapped differences during high-dose [dexmedetomidine, ketamine] infusions = [-1.93, -0.87] dB, 99% CI = [-4.16 to -0.56, -1.62 to -0.18] dB, P = [0.006, 0.019]; low-dose ketamine had no statistically significant decreases during the infusion). Recovery time differences with parabrachial nucleus excitation were not statistically significant for dexmedetomidine (median difference for [low, high] dose = [1.63, 11.01] min, 95% CI = [-20.06 to 14.14, -20.84 to 23.67] min, P = [0.945, 0.297]) nor low-dose ketamine (median difference = 12.82 [95% CI: -3.20 to 39.58] min, P = 0.109) but were significantly longer for high-dose ketamine (median difference = 11.38 [95% CI: 1.81 to 24.67] min, P = 0.016). CONCLUSIONS These results suggest that the effectiveness of parabrachial nucleus excitation to change the neurophysiologic and behavioral effects of anesthesia depends on the anesthetic's molecular target. EDITOR’S PERSPECTIVE
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Abstract
General anesthesia serves a critically important function in the clinical care of human patients. However, the anesthetized state has foundational implications for biology because anesthetic drugs are effective in organisms ranging from paramecia, to plants, to primates. Although unconsciousness is typically considered the cardinal feature of general anesthesia, this endpoint is only strictly applicable to a select subset of organisms that are susceptible to being anesthetized. We review the behavioral endpoints of general anesthetics across species and propose the isolation of an organism from its environment - both in terms of the afferent arm of sensation and the efferent arm of action - as a generalizable definition. We also consider the various targets and putative mechanisms of general anesthetics across biology and identify key substrates that are conserved, including cytoskeletal elements, ion channels, mitochondria, and functionally coupled electrical or neural activity. We conclude with a unifying framework related to network function and suggest that general anesthetics - from single cells to complex brains - create inefficiency and enhance modularity, leading to the dissociation of functions both within an organism and between the organism and its surroundings. Collectively, we demonstrate that general anesthesia is not restricted to the domain of modern medicine but has broad biological relevance with wide-ranging implications for a diverse array of species.
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Affiliation(s)
- Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, 3620 Hamilton Walk, 334 John Morgan Building, Philadelphia, PA 19104, USA; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Translational Research Laboratories, 125 S. 31st St., Philadelphia, PA 19104-3403, USA; Mahoney Institute for Neuroscience, University of Pennsylvania, Clinical Research Building, 415 Curie Blvd, Philadelphia, PA 19104, USA.
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, 7433 Medical Science Building 1, 1150 West Medical Center Drive, Ann Arbor, MI 48109, USA; Center for Consciousness Science, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Escape From Oblivion: Neural Mechanisms of Emergence From General Anesthesia. Anesth Analg 2019; 128:726-736. [PMID: 30883418 DOI: 10.1213/ane.0000000000004006] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The question of how general anesthetics suppress consciousness has persisted since the mid-19th century, but it is only relatively recently that the field has turned its focus to a systematic understanding of emergence. Once assumed to be a purely passive process, spontaneously occurring as residual levels of anesthetics dwindle below a critical value, emergence from general anesthesia has been reconsidered as an active and controllable process. Emergence is driven by mechanisms that can be distinct from entry to the anesthetized state. In this narrative review, we focus on the burgeoning scientific understanding of anesthetic emergence, summarizing current knowledge of the neurotransmitter, neuromodulators, and neuronal groups that prime the brain as it prepares for its journey back from oblivion. We also review evidence for possible strategies that may actively bias the brain back toward the wakeful state.
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The Locus Coeruleus Modulates Intravenous General Anesthesia of Zebrafish via a Cooperative Mechanism. Cell Rep 2019; 24:3146-3155.e3. [PMID: 30231998 DOI: 10.1016/j.celrep.2018.08.046] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 06/17/2018] [Accepted: 08/16/2018] [Indexed: 01/03/2023] Open
Abstract
How general anesthesia causes loss of consciousness has been a mystery for decades. It is generally thought that arousal-related brain nuclei, including the locus coeruleus (LC), are involved. Here, by monitoring locomotion behaviors and neural activities, we developed a larval zebrafish model for studying general anesthesia induced by propofol and etomidate, two commonly used intravenous anesthetics. Local lesion of LC neurons via two-photon laser-based ablation or genetic depletion of norepinephrine (NE; a neuromodulator released by LC neurons) via CRISPR/Cas9-based mutation of dopamine-β-hydroxylase (dbh) accelerates induction into and retards emergence from general anesthesia. Mechanistically, in vivo whole-cell recording revealed that both anesthetics suppress LC neurons' activity through a cooperative mechanism, inhibiting presynaptic excitatory inputs and inducing GABAA receptor-mediated hyperpolarization of these neurons. Thus, our study indicates that the LC-NE system plays a modulatory role in both induction of and emergence from intravenous general anesthesia.
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Ma Y, Miracca G, Yu X, Harding EC, Miao A, Yustos R, Vyssotski AL, Franks NP, Wisden W. Galanin Neurons Unite Sleep Homeostasis and α2-Adrenergic Sedation. Curr Biol 2019; 29:3315-3322.e3. [PMID: 31543455 PMCID: PMC6868514 DOI: 10.1016/j.cub.2019.07.087] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 05/24/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022]
Abstract
Our urge to sleep increases with time spent awake, until sleep becomes inescapable. The sleep following sleep deprivation is longer and deeper, with an increased power of delta (0.5–4 Hz) oscillations, a phenomenon termed sleep homeostasis [1, 2, 3, 4]. Although widely expressed genes regulate sleep homeostasis [1, 4, 5, 6, 7, 8, 9, 10] and the process is tracked by somnogens and phosphorylation [1, 3, 7, 11, 12, 13, 14], at the circuit level sleep homeostasis has remained mysterious. Previously, we found that sedation induced with α2-adrenergic agonists (e.g., dexmedetomidine) and sleep homeostasis both depend on the preoptic (PO) hypothalamus [15, 16]. Dexmedetomidine, increasingly used for long-term sedation in intensive care units [17], induces a non-rapid-eye-movement (NREM)-like sleep but with undesirable hypothermia [18, 19]. Within the PO, various neuronal subtypes (e.g., GABA/galanin and glutamate/NOS1) induce NREM sleep [20, 21, 22] and concomitant body cooling [21, 22]. This could be because NREM sleep’s restorative effects depend on lower body temperature [23, 24]. Here, we show that mice with lesioned PO galanin neurons have reduced sleep homeostasis: in the recovery sleep following sleep deprivation there is a diminished increase in delta power, and the mice catch up little on lost sleep. Furthermore, dexmedetomidine cannot induce high-power delta oscillations or sustained hypothermia. Some hours after dexmedetomidine administration to wild-type mice there is a rebound in delta power when they enter normal NREM sleep, reminiscent of emergence from torpor. This delta rebound is reduced in mice lacking PO galanin neurons. Thus, sleep homeostasis and dexmedetomidine-induced sedation require PO galanin neurons and likely share common mechanisms. This is the first identification of a cell type underlying sleep homeostasis Preoptic galanin neurons are essential for sleep homeostasis Galanin neurons mediate the sedative and hypothermic actions of dexmedetomidine Dexmedetomidine causes an EEG delta power rebound dependent on galanin neurons
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Affiliation(s)
- Ying Ma
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Giulia Miracca
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Xiao Yu
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Edward C Harding
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Andawei Miao
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; UK Dementia Research Institute, Imperial College, London SW7 2AZ, UK
| | - Raquel Yustos
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich and ETH Zurich, Zurich 8057, Switzerland
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; UK Dementia Research Institute, Imperial College, London SW7 2AZ, UK.
| | - William Wisden
- Department of Life Sciences, Imperial College, London SW7 2AZ, UK; UK Dementia Research Institute, Imperial College, London SW7 2AZ, UK.
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16
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Mansouri MT, Fidler JA, Meng QC, Eckenhoff RG, García PS. Sex effects on behavioral markers of emergence from propofol and isoflurane anesthesia in rats. Behav Brain Res 2019; 367:59-67. [PMID: 30898682 DOI: 10.1016/j.bbr.2019.03.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/12/2019] [Accepted: 03/15/2019] [Indexed: 01/18/2023]
Abstract
Clinical studies have demonstrated sex-related differences in recovery from surgical anesthesia. This study aimed to characterize the emergence pattern following two anesthesia regimens in both sexes of rats. We considered six different markers of emergence from anesthesia: sigh, eye blinking, forelimb movement, mastication, neck extension, and recovery of the righting reflex (RORR). Spontaneous motor activity 24 h after the anesthesia induction was also examined. Our results showed that the rank order of the emergence latency after intraperitoneal propofol, PRO, exposure was forelimb movement < sigh < blink < mastication < neck extension < RORR, while after inhaled isoflurane, ISO, anesthesia the sequence was changed as sigh < blink < mastication < forelimb movement < neck extension < RORR in both male and female rats. Moreover, the latency to emergence after PRO in female rats was significantly higher than male rats, although following ISO there was no difference between the sexes (P < 0.001; P > 0.05, respectively). Open-field testing revealed no difference in PRO and ISO spontaneous locomotor activity due to drug administration (P > 0.05). These two anesthetics presented different emergence sequences. Although clinical data suggests that females arouse faster than males from anesthesia with propofol, our intraperitoneal technique in a rodent model had the opposite effect. Pharmacokinetic analysis demonstrated increased absorption of injected propofol for the female rats in our study, emphasizing the role of sexual dimorphism in drug distribution in rodents. Despite these pharmacokinetic differences, the pharmacodynamic effects of the drugs were remarkably consistent among both sexes through emergence.
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Affiliation(s)
- Mohammed Taghi Mansouri
- Neuroanesthesia Laboratory, Atlanta VA Medical Center/Emory University, Atlanta, GA, USA; Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA; Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA
| | - Jonathan A Fidler
- Neuroanesthesia Laboratory, Atlanta VA Medical Center/Emory University, Atlanta, GA, USA; Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Qing Cheng Meng
- Department of Anesthesiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Roderic G Eckenhoff
- Department of Anesthesiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul S García
- Neuroanesthesia Laboratory, Atlanta VA Medical Center/Emory University, Atlanta, GA, USA; Department of Anesthesiology, Emory University School of Medicine, Atlanta, GA, USA; Department of Anesthesiology, Columbia University Medical Center, New York, NY, USA.
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17
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Hemmings HC, Riegelhaupt PM, Kelz MB, Solt K, Eckenhoff RG, Orser BA, Goldstein PA. Towards a Comprehensive Understanding of Anesthetic Mechanisms of Action: A Decade of Discovery. Trends Pharmacol Sci 2019; 40:464-481. [PMID: 31147199 DOI: 10.1016/j.tips.2019.05.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 04/11/2019] [Accepted: 05/03/2019] [Indexed: 12/30/2022]
Abstract
Significant progress has been made in the 21st century towards a comprehensive understanding of the mechanisms of action of general anesthetics, coincident with progress in structural biology and molecular, cellular, and systems neuroscience. This review summarizes important new findings that include target identification through structural determination of anesthetic binding sites, details of receptors and ion channels involved in neurotransmission, and the critical roles of neuronal networks in anesthetic effects on memory and consciousness. These recent developments provide a comprehensive basis for conceptualizing pharmacological control of amnesia, unconsciousness, and immobility.
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Affiliation(s)
- Hugh C Hemmings
- Departments of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA; Departments of Pharmacology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Paul M Riegelhaupt
- Departments of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA
| | - Max B Kelz
- Department of Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, 3620 Hamilton Walk, 305 John Morgan, Philadelphia, PA 19104, USA
| | - Ken Solt
- Department of Anaesthesia, Harvard Medical School, GRB 444, 55 Fruit St., Boston, MA 02114, USA; Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania Perelman School of Medicine, 3620 Hamilton Walk, 305 John Morgan, Philadelphia, PA 19104, USA
| | - Beverley A Orser
- Departments of Anesthesia and Physiology, Room 3318 Medical Sciences Building, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Peter A Goldstein
- Departments of Anesthesiology, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA; Departments of Medicine, Weill Cornell Medicine, 1300 York Avenue, New York, NY 10065, USA.
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18
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Sepúlveda PO, Tapia LF, Monsalves S. Neural inertia and differences between loss of and recovery from consciousness during total intravenous anaesthesia: a narrative review. Anaesthesia 2019; 74:801-809. [DOI: 10.1111/anae.14609] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2019] [Indexed: 12/31/2022]
Affiliation(s)
- P. O. Sepúlveda
- Department of Anaesthesia and Pain Clínica Alemana Santiago de Chile Chile
- Department of Anaesthesia , Universidad del Desarrollo Santiago de Chile Chile
| | - L. F. Tapia
- Consultant, Department of Anaesthesia and Pain Clínica Alemana Santiago de Chile Chile
| | - S. Monsalves
- Consultant, Department of Anaesthesia and Pain Clínica Alemana Santiago de Chile Chile
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Activation of Parabrachial Nucleus Glutamatergic Neurons Accelerates Reanimation from Sevoflurane Anesthesia in Mice. Anesthesiology 2019; 130:106-118. [DOI: 10.1097/aln.0000000000002475] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abstract
EDITOR’S PERSPECTIVE
What We Already Know about This Topic
The parabrachial nucleus is a brainstem region involved in arousal.
Brain regions involved in arousal regulate anesthetic induction and emergence.
What This Article Tells Us That Is New
Using chemogenetic techniques, activation of parabrachial nucleus glutamatergic neurons prolonged anesthetic induction and hastened emergence in mice. Inhibition of these neurons provided opposite effects.
Modulating the activity of arousal centers may provide an approach to controlling the duration of general anesthesia.
Background
The parabrachial nucleus (PBN), which is a brainstem region containing glutamatergic neurons, is a key arousal nucleus. Injuries to the area often prevent patient reanimation. Some studies suggest that brain regions that control arousal and reanimation are a key part of the anesthesia recovery. Therefore, we hypothesize that the PBN may be involved in regulating emergence from anesthesia.
Methods
We investigated the effects of specific activation or inhibition of PBN glutamatergic neurons on sevoflurane general anesthesia using the chemogenetic “designer receptors exclusively activated by designer drugs” approach. Optogenetic methods combined with polysomnographic recordings were used to explore the effects of transient activation of PBN glutamatergic neuron on sevoflurane anesthesia. Immunohistochemical techniques are employed to reveal the mechanism by which PBN regulated sevoflurane anesthesia.
Results
Chemogenetic activation of PBN glutamatergic neurons by intraperitoneal injections of clozapine-N-oxide decreased emergence time (mean ± SD, control vs. clozapine-N-oxide, 55 ± 24 vs. 15 ± 9 s, P = 0.0002) caused by sevoflurane inhalation and prolonged induction time (70 ± 15 vs. 109 ± 38 s, n = 9, P = 0.012) as well as the ED50 of sevoflurane (1.48 vs. 1.60%, P = 0.0002), which was characterized by a rightward shift of the loss of righting reflex cumulative curve. In contrast, chemogenetic inhibition of PBN glutamatergic neurons slightly increased emergence time (56 ± 26 vs. 87 ± 26 s, n = 8, P = 0.034). Moreover, instantaneous activation of PBN glutamatergic neurons expressing channelrhodopsin-2 during steady-state general anesthesia with sevoflurane produced electroencephalogram evidence of cortical arousal. Immunohistochemical experiments showed that activation of PBN induced excitation of cortical and subcortical arousal nuclei during sevoflurane anesthesia.
Conclusions
Activation of PBN glutamatergic neurons is helpful to accelerate the transition from general anesthesia to an arousal state, which may provide a new strategy in shortening the recovery time after sevoflurane anesthesia.
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20
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Feng ZX, Dong H, Qu WM, Zhang W. Oral Delivered Dexmedetomidine Promotes and Consolidates Non-rapid Eye Movement Sleep via Sleep-Wake Regulation Systems in Mice. Front Pharmacol 2018; 9:1196. [PMID: 30568589 PMCID: PMC6290063 DOI: 10.3389/fphar.2018.01196] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/28/2018] [Indexed: 01/11/2023] Open
Abstract
Dexmedetomidine, a highly selective α2-adrenergic agonist, is widely used in clinical anesthesia and ICU sedation. Recent studies have found that dexmedetomidine-induced sedation resembles the recovery sleep that follows sleep deprivation, but whether orally delivered dexmedetomidine can be a candidate for the treatment of insomnia remains unclear. In this study, we estimated the sedative effects of orally delivered dexmedetomidine by spontaneous locomotor activity (LMA), and then evaluated the hypnotic effects of dexmedetomidine on sleep–wake profiles during the dark and light phase using electroencephalography/electromyogram (EEG/EMG), respectively. Using c-Fos staining, we explored the effects of dexmedetomidine on the cerebral cortex and the sub-cortical sleep–wake regulation systems. The results showed that orally delivered dexmedetomidine at 2 h into the dark cycle reduced LMA and wakefulness in a dose-dependent manner, which was consistent with the increase in non-rapid eye movement sleep (NREM sleep). However, dexmedetomidine also induced a rebound in LMA, wake and rapid eye movement sleep (REM sleep) in the later stage. In addition, orally delivered dexmedetomidine 100 μg/kg at 2 h into the light cycle shortened the latency to NREM sleep and increased the duration of NREM sleep for 6 h, while decreased REM sleep for 6 h. Sleep architecture analysis showed that dexmedetomidine stabilized the sleep structure during the light phase by decreasing sleep–wake transition and increasing long-term NREM sleep (durations of 1024–2024 s and >2024 s) while reducing short-term wakefulness (duration of 4–16 s). Unlike the classic hypnotic diazepam, dexmedetomidine also increased the delta power in the EEG spectra of NREM sleep, especially at the frequency of 1.75–3.25 Hz, while ranges of 0.5–1.0 Hz were decreased. Immunohistochemical analysis showed that orally delivered dexmedetomidine 100 μg/kg at 2 h into the dark cycle decreased c-Fos expression in the cerebral cortex and sub-cortical arousal systems, while it increased c-Fos expression in the neurons of the ventrolateral preoptic nucleus. These results indicate that orally delivered dexmedetomidine can induce sedative and hypnotic effects by exciting the sleep-promoting nucleus and inhibiting the wake-promoting areas.
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Affiliation(s)
- Zhen-Xin Feng
- Department of Anesthesiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Hui Dong
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Wei-Min Qu
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Wei Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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21
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Wasilczuk AZ, Maier KL, Kelz MB. The Mouse as a Model Organism for Assessing Anesthetic Sensitivity. Methods Enzymol 2018; 602:211-228. [PMID: 29588030 DOI: 10.1016/bs.mie.2018.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The mouse has been used in many medical fields as a powerful model to reveal the genetic basis of human physiology and disease. The past two decades have witnessed an enormous wealth of genetic and informatic resources dedicated to this humble organism. With the ongoing revolution in mapping neural circuitry governing behavior, the mouse is an ideal model organism poised to unravel the mysteries of general anesthetic action. This chapter will describe and provide guidelines for anesthetic phenotyping in the mouse including both motor-dependent and motor-independent assessments.
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Affiliation(s)
- Andrzej Z Wasilczuk
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States
| | - Kaitlyn L Maier
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States
| | - Max B Kelz
- University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States; Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, United States.
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22
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Yu X, Franks NP, Wisden W. Sleep and Sedative States Induced by Targeting the Histamine and Noradrenergic Systems. Front Neural Circuits 2018; 12:4. [PMID: 29434539 PMCID: PMC5790777 DOI: 10.3389/fncir.2018.00004] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/11/2018] [Indexed: 01/07/2023] Open
Abstract
Sedatives target just a handful of receptors and ion channels. But we have no satisfying explanation for how activating these receptors produces sedation. In particular, do sedatives act at restricted brain locations and circuitries or more widely? Two prominent sedative drugs in clinical use are zolpidem, a GABAA receptor positive allosteric modulator, and dexmedetomidine (DEX), a selective α2 adrenergic receptor agonist. By targeting hypothalamic neuromodulatory systems both drugs induce a sleep-like state, but in different ways: zolpidem primarily reduces the latency to NREM sleep, and is a controlled substance taken by many people to help them sleep; DEX produces prominent slow wave activity in the electroencephalogram (EEG) resembling stage 2 NREM sleep, but with complications of hypothermia and lowered blood pressure—it is used for long term sedation in hospital intensive care units—under DEX-induced sedation patients are arousable and responsive, and this drug reduces the risk of delirium. DEX, and another α2 adrenergic agonist xylazine, are also widely used in veterinary clinics to sedate animals. Here we review how these two different classes of sedatives, zolpidem and dexmedetomideine, can selectively interact with some nodal points of the circuitry that promote wakefulness allowing the transition to NREM sleep. Zolpidem enhances GABAergic transmission onto histamine neurons in the hypothalamic tuberomammillary nucleus (TMN) to hasten the transition to NREM sleep, and DEX interacts with neurons in the preoptic hypothalamic area that induce sleep and body cooling. This knowledge may aid the design of more precise acting sedatives, and at the same time, reveal more about the natural sleep-wake circuitry.
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Affiliation(s)
- Xiao Yu
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
| | - William Wisden
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
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23
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Pharmacological Modulation of Noradrenergic Arousal Circuitry Disrupts Functional Connectivity of the Locus Ceruleus in Humans. J Neurosci 2017. [PMID: 28626012 DOI: 10.1523/jneurosci.0446-17.2017] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
State-dependent activity of locus ceruleus (LC) neurons has long suggested a role for noradrenergic modulation of arousal. However, in vivo insights into noradrenergic arousal circuitry have been constrained by the fundamental inaccessibility of the human brain for invasive studies. Functional magnetic resonance imaging (fMRI) studies performed during site-specific pharmacological manipulations of arousal levels may be used to study brain arousal circuitry. Dexmedetomidine is an anesthetic that alters the level of arousal by selectively targeting α2 adrenergic receptors on LC neurons, resulting in reduced firing rate and norepinephrine release. Thus, we hypothesized that dexmedetomidine-induced altered arousal would manifest with reduced functional connectivity between the LC and key brain regions involved in the regulation of arousal. To test this hypothesis, we acquired resting-state fMRI data in right-handed healthy volunteers 18-36 years of age (n = 15, 6 males) at baseline, during dexmedetomidine-induced altered arousal, and recovery states. As previously reported, seed-based resting-state fMRI analyses revealed that the LC was functionally connected to a broad network of regions including the reticular formation, basal ganglia, thalamus, posterior cingulate cortex (PCC), precuneus, and cerebellum. Functional connectivity of the LC to only a subset of these regions (PCC, thalamus, and caudate nucleus) covaried with the level of arousal. Functional connectivity of the PCC to the ventral tegmental area/pontine reticular formation and thalamus, in addition to the LC, also covaried with the level of arousal. We propose a framework in which the LC, PCC, thalamus, and basal ganglia comprise a functional arousal circuitry.SIGNIFICANCE STATEMENT Electrophysiological studies of locus ceruleus (LC) neurons have long suggested a role for noradrenergic mechanisms in mediating arousal. However, the fundamental inaccessibility of the human brain for invasive studies has limited a precise understanding of putative brain regions that integrate with the LC to regulate arousal. Our results suggest that the PCC, thalamus, and basal ganglia are key components of a LC-noradrenergic arousal circuit.
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Keilholz SD, Pan WJ, Billings J, Nezafati M, Shakil S. Noise and non-neuronal contributions to the BOLD signal: applications to and insights from animal studies. Neuroimage 2016; 154:267-281. [PMID: 28017922 DOI: 10.1016/j.neuroimage.2016.12.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/21/2016] [Accepted: 12/08/2016] [Indexed: 01/08/2023] Open
Abstract
The BOLD signal reflects hemodynamic events within the brain, which in turn are driven by metabolic changes and neural activity. However, the link between BOLD changes and neural activity is indirect and can be influenced by a number of non-neuronal processes. Motion and physiological cycles have long been known to affect the BOLD signal and are present in both humans and animal models. Differences in physiological baseline can also contribute to intra- and inter-subject variability. The use of anesthesia, common in animal studies, alters neural activity, vascular tone, and neurovascular coupling. Most intriguing, perhaps, are the contributions from other processes that do not appear to be neural in origin but which may provide information about other aspects of neurophysiology. This review discusses different types of noise and non-neuronal contributors to the BOLD signal, sources of variability for animal studies, and insights to be gained from animal models.
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Affiliation(s)
- Shella D Keilholz
- Wallace H. Coulter Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States; Neuroscience Program, Emory University, Atlanta, GA, United States.
| | - Wen-Ju Pan
- Wallace H. Coulter Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States
| | - Jacob Billings
- Neuroscience Program, Emory University, Atlanta, GA, United States
| | - Maysam Nezafati
- Wallace H. Coulter Department of Biomedical Engineering, Emory University/Georgia Institute of Technology, Atlanta, GA, United States
| | - Sadia Shakil
- Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, United States
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25
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Sukhotinsky I, Minert A, Soja P, Devor M. Mesopontine Switch for the Induction of General Anesthesia by Dedicated Neural Pathways. Anesth Analg 2016; 123:1274-1285. [DOI: 10.1213/ane.0000000000001489] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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26
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Hara M, Zhou ZY, Hemmings HC. α2-Adrenergic Receptor and Isoflurane Modulation of Presynaptic Ca2+ Influx and Exocytosis in Hippocampal Neurons. Anesthesiology 2016; 125:535-46. [PMID: 27337223 PMCID: PMC4988866 DOI: 10.1097/aln.0000000000001213] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Evidence indicates that the anesthetic-sparing effects of α2-adrenergic receptor (AR) agonists involve α2A-AR heteroreceptors on nonadrenergic neurons. Since volatile anesthetics inhibit neurotransmitter release by reducing synaptic vesicle (SV) exocytosis, the authors hypothesized that α2-AR agonists inhibit nonadrenergic SV exocytosis and thereby potentiate presynaptic inhibition of exocytosis by isoflurane. METHODS Quantitative imaging of fluorescent biosensors of action potential-evoked SV exocytosis (synaptophysin-pHluorin) and Ca influx (GCaMP6) were used to characterize presynaptic actions of the clinically used α2-AR agonists dexmedetomidine and clonidine, and their interaction with isoflurane, in cultured rat hippocampal neurons. RESULTS Dexmedetomidine (0.1 μM, n = 10) or clonidine (0.5 μM, n = 8) inhibited action potential-evoked exocytosis (54 ± 5% and 59 ± 8% of control, respectively; P < 0.001). Effects on exocytosis were blocked by the subtype-nonselective α2-AR antagonist atipamezole or the α2A-AR-selective antagonist BRL 44408 but not by the α2C-AR-selective antagonist JP 1302. Dexmedetomidine inhibited exocytosis and presynaptic Ca influx without affecting Ca coupling to exocytosis, consistent with an effect upstream of Ca-exocytosis coupling. Exocytosis coupled to both N-type and P/Q-type Ca channels was inhibited by dexmedetomidine or clonidine. Dexmedetomidine potentiated inhibition of exocytosis by 0.7 mM isoflurane (to 42 ± 5%, compared to 63 ± 8% for isoflurane alone; P < 0.05). CONCLUSIONS Hippocampal SV exocytosis is inhibited by α2A-AR activation in proportion to reduced Ca entry. These effects are additive with those of isoflurane, consistent with a role for α2A-AR presynaptic heteroreceptor inhibition of nonadrenergic synaptic transmission in the anesthetic-sparing effects of α2A-AR agonists.
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Affiliation(s)
- Masato Hara
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
- Department of Anesthesiology, Kurume University School of Medicine, Kurume, Fukuoka 830-0011, Japan
| | - Zhen-Yu Zhou
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
| | - Hugh C. Hemmings
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065, USA
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA
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Sen T, Sen N. Isoflurane-induced inactivation of CREB through histone deacetylase 4 is responsible for cognitive impairment in developing brain. Neurobiol Dis 2016; 96:12-21. [PMID: 27544482 DOI: 10.1016/j.nbd.2016.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/13/2016] [Accepted: 08/16/2016] [Indexed: 12/14/2022] Open
Abstract
Anesthetics including isoflurane are known to induce neuronal dysfunction in the developing brain, however, the underlying mechanism is mostly unknown. The transcriptional activation of CREB (cyclic AMP response element binding protein) and the alterations in acetylation of histones modulated by several histone deacetylases such as HDAC4 (histone deacetylase 4) are known to contribute to synaptic plasticity in the brain. Here we have shown that administration of isoflurane (1.4%) for 2h leads to transcriptional inactivation of CREB which results in loss of dendritic outgrowth and decreased expression level of proteins essential for memory and cognitive functions, such as BDNF, and c-fos in the developing brain of mice at postnatal day 7 (PND7). To elucidate the molecular mechanism, we found that exposure to isoflurane leads to an increase in nuclear translocation of HDAC4, which interacts with CREB in the nucleus. This event, in turn, results in a decrease in interaction between an acetyltransferase, CBP, and CREB that ultimately leads to transcriptional inactivation of CREB. As a result, the expression level of BDNF, and c-fos were significantly down-regulated after administration of isoflurane in PND7 brain. Depletion of HDAC4 in PND7 brain rescues the transcriptional activation of CREB along with augmentation in the level of the expression level of BDNF and c-fos. Moreover, administration of lentiviral particles of HDAC4 RNAi in primary neurons rescues neurite outgrowth following isoflurane treatment. Taken together, our study suggests that HDAC4-induced transcriptional inactivation of CREB is responsible for isoflurane-induced cognitive dysfunction in the brain.
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Affiliation(s)
- Tanusree Sen
- University of Georgia, Department of Veterinary, USA
| | - Nilkantha Sen
- Augusta University, Department of Neuroscience and Regenerative Medicine, 1120 15th Street, CA 2018, Augusta, GA 30907, USA.
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Zhou X, Wang Y, Zhang C, Wang M, Zhang M, Yu L, Yan M. The Role of Dopaminergic VTA Neurons in General Anesthesia. PLoS One 2015; 10:e0138187. [PMID: 26398236 PMCID: PMC4580504 DOI: 10.1371/journal.pone.0138187] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/27/2015] [Indexed: 01/18/2023] Open
Abstract
Recent studies have demonstrated that the central dopaminergic system is implicated in the mechanism underlying general anesthesia. Here, we investigated whether dopaminergic ventral tegmental area (VTA) neurons participate in general anesthesia. Dopaminergic VTA neurons were selectively ablated from male Sprague Dawley rats via the bilateral infusion of 6-hydroxydopamine (6-OHDA) into the VTA. Two weeks after infusion, the number of dopaminergic neurons in the bilateral VTA was markedly reduced in the 6-OHDA-treated rats compared with the vehicle-treated rats. These bilateral VTA lesions significantly prolonged the recovery time for propofol but did not significantly alter its onset time or 50% effective dose (ED50) value. In addition, the anesthetic responses to isoflurane and ketamine were unaffected by the VTA lesions. Our findings suggested that dopaminergic VTA neurons might be involved in the emergence from propofol anesthesia.
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Affiliation(s)
- Xuelong Zhou
- Department of Anesthesiology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
| | - Yin Wang
- Department of Anesthesiology, The Tai Zhou People’s Hospital, Taizhou, 225300, China
| | - Chenjing Zhang
- Department of Gastroenterology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
| | - Min Wang
- Jiangsu Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, 221000, China
| | - Mei Zhang
- Jiangsu Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, 221000, China
| | - LiNa Yu
- Department of Anesthesiology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
| | - Min Yan
- Department of Anesthesiology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310000, China
- * E-mail:
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29
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The 9th International Symposium on Memory and Awareness in Anesthesia (MAA9). Br J Anaesth 2015. [DOI: 10.1093/bja/aev204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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30
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Zhang Z, Ferretti V, Güntan İ, Moro A, Steinberg EA, Ye Z, Zecharia AY, Yu X, Vyssotski AL, Brickley SG, Yustos R, Pillidge ZE, Harding EC, Wisden W, Franks NP. Neuronal ensembles sufficient for recovery sleep and the sedative actions of α2 adrenergic agonists. Nat Neurosci 2015; 18:553-561. [PMID: 25706476 PMCID: PMC4836567 DOI: 10.1038/nn.3957] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/21/2015] [Indexed: 12/31/2022]
Abstract
Do sedatives engage natural sleep pathways? It is usually assumed that anesthetic-induced sedation and loss-of-righting-reflex (LORR) arise by influencing the same circuitry to lesser or greater extents. For the α2 adrenergic receptor agonist dexmedetomidine, we find that sedation and LORR are in fact distinct states, requiring different brain areas, the preoptic hypothalamic area and locus coeruleus (LC) respectively. Selective knockdown of α2A adrenergic receptors from the LC abolished dexmedetomidine-induced LORR, but not sedation. Instead, we found that dexmedetomidine-induced sedation resembles the deep recovery sleep that follows sleep deprivation. We used TetTag-pharmacogenetics in mice to functionally mark neurons activated in the preoptic hypothalamus during dexmedetomidine-induced sedation or recovery sleep. The neuronal ensembles could then be selectively reactivated. In both cases NREM sleep, with the accompanying drop in body temperature, was recapitulated. Thus α2 adrenergic receptor-induced sedation and recovery sleep share hypothalamic circuitry sufficient for producing these behavioral states.
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Affiliation(s)
- Zhe Zhang
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Valentina Ferretti
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - İlke Güntan
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Alessandro Moro
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Eleonora A Steinberg
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Zhiwen Ye
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Anna Y Zecharia
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Xiao Yu
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zürich/ETH Zürich, Winterthurerstrasse 190, CH-8057, Zürich, Switzerland
| | - Stephen G Brickley
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Raquel Yustos
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Zoe E Pillidge
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Edward C Harding
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - William Wisden
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
| | - Nicholas P Franks
- Department of Life Sciences Imperial College London, South Kensington, SW7 2AZ, U.K
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α2-Adrenergic stimulation of the ventrolateral preoptic nucleus destabilizes the anesthetic state. J Neurosci 2015; 34:16385-96. [PMID: 25471576 DOI: 10.1523/jneurosci.1135-14.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The sleep-promoting ventrolateral preoptic nucleus (VLPO) shares reciprocal inhibitory inputs with wake-active neuronal nuclei, including the locus ceruleus. Electrophysiologically, sleep-promoting neurons in the VLPO are directly depolarized by the general anesthetic isoflurane and hyperpolarized by norepinephrine, a wake-promoting neurotransmitter. However, the integration of these competing influences on the VLPO, a sleep- and anesthetic-active structure, has yet to be evaluated in either brain slices in vitro or the intact organism. Single-cell multiplex RT-PCR conducted on both isoflurane-activated, putative sleep-promoting VLPO neurons and neighboring, state-indifferent VLPO neurons in mouse brain slices revealed widespread expression of α2A-, α2B- and α2C-adrenergic receptors in both populations. Indeed, both norepinephrine and the highly selective α2 agonist dexmedetomidine each reversed the VLPO depolarization induced by isoflurane in slices in vitro. When microinjected directly into the VLPO of a mouse lightly anesthetized with isoflurane, dexmedetomidine increased behavioral arousal and reduced the depressant effects of isoflurane on barrel cortex somatosensory-evoked potentials but failed to elicit spectral changes in spontaneous EEG. Based on these observations, we conclude that local modulation of α-adrenergic activity in the VLPO destabilizes, but does not fully antagonize, the anesthetic state, thus priming the brain for anesthetic emergence.
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32
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Selective blockade of N-methyl-D-aspartate channels in combination with dopamine receptor antagonism induces loss of the righting reflex in mice, but not immobility. Psychopharmacology (Berl) 2015; 232:39-46. [PMID: 24879496 DOI: 10.1007/s00213-014-3634-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 05/06/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE The selective N-methyl-D-aspartate (NMDA) channel blocker MK-801 is known to induce no loss of the righting reflex (LORR) and to stimulate catecholaminergic (CAergic) neurons in rodents, playing a crucial role in arousal. OBJECTIVES We examined whether MK-801 in combination with CA receptor ligands, which inhibit CAergic neuronal activities, could induce anesthesia including LORR. METHODS All drugs were administered systemically to mice. To assess anesthesia, three different behaviors were used: loss of nociceptive response (analgesia in the free-moving state without LORR), LORR, and loss of movement in response to noxious stimulation (immobility under LORR). RESULTS A very large dose of MK-801 (50 mg/kg) induced neither analgesia nor LORR. In contrast, MK-801 in combination with a small dose of the dopamine (DA) receptor antagonist haloperidol (0.2 mg/kg) dose-dependently produced LORR with a 50 % effective dose (ED50) of 1.6 (0.9-3.0; 95 % confidence limit) mg/kg, but not immobility. The α2-adrenoceptor agonist dexmedetomidine induced not only analgesia, but also immobility in animals treated with MK-801 (5 mg/kg) plus haloperidol (0.2 mg/kg), which then lost their righting reflex. The ED50 value of 0.26 (0.10-0.66) mg/kg (various doses of dexmedetomidine plus a fixed dose of MK-801 and haloperidol) for immobility was approximately three-fold larger than that of 0.09 (0.03-0.23) mg/kg (dexmedetomidine plus vehicle saline) for analgesia. This may occur, as LORR induced by MK-801 plus haloperidol inhibits the pain suppression system. The other ligands had little or no effect. CONCLUSIONS The DAergic stimulant actions of MK-801 may mask its LORR effects by NMDA channel blockade.
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Leung LS, Luo T, Ma J, Herrick I. Brain areas that influence general anesthesia. Prog Neurobiol 2014; 122:24-44. [PMID: 25172271 DOI: 10.1016/j.pneurobio.2014.08.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 08/03/2014] [Accepted: 08/19/2014] [Indexed: 10/24/2022]
Abstract
This document reviews the literature on local brain manipulation of general anesthesia in animals, focusing on behavioral and electrographic effects related to hypnosis or loss of consciousness. Local inactivation or lesion of wake-active areas, such as locus coeruleus, dorsal raphe, pedunculopontine tegmental nucleus, perifornical area, tuberomammillary nucleus, ventral tegmental area and basal forebrain, enhanced general anesthesia. Anesthesia enhancement was shown as a delayed emergence (recovery of righting reflex) from anesthesia or a decrease in the minimal alveolar concentration that induced loss of righting. Local activation of various wake-active areas, including pontis oralis and centromedial thalamus, promoted behavioral or electrographic arousal during maintained anesthesia and facilitated emergence. Lesion of the sleep-active ventrolateral preoptic area resulted in increased wakefulness and decreased isoflurane sensitivity, but only for 6 days after lesion. Inactivation of any structure within limbic circuits involving the medial septum, hippocampus, nucleus accumbens, ventral pallidum, and ventral tegmental area, amygdala, entorhinal and piriform cortex delayed emergence from anesthesia, and often reduced anesthetic-induced behavioral excitation. In summary, the concept that anesthesia works on the sleep-wake system has received strong support from studies that inactivated/lesioned or activated wake-active areas, and weak support from studies that lesioned sleep-active areas. In addition to the conventional wake-sleep areas, limbic structures such as the medial septum, hippocampus and prefrontal cortex are also involved in the behavioral response to general anesthesia. We suggest that hypnosis during general anesthesia may result from disrupting the wake-active neuronal activities in multiple areas and suppressing an atropine-resistant cortical activation associated with movements.
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Affiliation(s)
- L Stan Leung
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada N6A 5C1.
| | - Tao Luo
- Department of Anesthesiology, Peking University, Shenzhen Hospital, China
| | - Jingyi Ma
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada N6A 5C1
| | - Ian Herrick
- Department of Anaesthesiology and Perioperative Medicine, The University of Western Ontario, London, Ontario, Canada N6A 5C1
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Mashour GA. Top-down mechanisms of anesthetic-induced unconsciousness. Front Syst Neurosci 2014; 8:115. [PMID: 25002838 PMCID: PMC4066704 DOI: 10.3389/fnsys.2014.00115] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 05/27/2014] [Indexed: 11/18/2022] Open
Abstract
The question of how structurally and pharmacologically diverse general anesthetics disrupt consciousness has persisted since the nineteenth century. There has traditionally been a significant focus on “bottom-up” mechanisms of anesthetic action, in terms of sensory processing, arousal systems, and structural scales. However, recent evidence suggests that the neural mechanisms of anesthetic-induced unconsciousness may involve a “top-down” process, which parallels current perspectives on the neurobiology of conscious experience itself. This article considers various arguments for top-down mechanisms of anesthetic-induced unconsciousness, with a focus on sensory processing and sleep-wake networks. Furthermore, recent theoretical work is discussed to highlight the possibility that top-down explanations may be causally sufficient, even assuming critical bottom-up events.
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Affiliation(s)
- George A Mashour
- Neuroscience Graduate Program, Department of Anesthesiology, Center for Consciousness Science, University of Michigan Medical School Ann Arbor, MI, USA
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Vazey EM, Aston-Jones G. Designer receptor manipulations reveal a role of the locus coeruleus noradrenergic system in isoflurane general anesthesia. Proc Natl Acad Sci U S A 2014; 111:3859-64. [PMID: 24567395 PMCID: PMC3956184 DOI: 10.1073/pnas.1310025111] [Citation(s) in RCA: 166] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mechanisms driving emergence from general anesthesia are not well understood. The noradrenergic brain nucleus locus coeruleus (LC) modulates arousal and may have effects on general anesthetic state. Using virally delivered designer receptors to specifically control LC norepinephrine (NE) neurons, we investigated the causal relationship between LC-NE activity and general anesthetic state under isoflurane. Selective activation of LC-NE neurons produced cortical electroencephalography (EEG) activation under continuous deep isoflurane anesthesia. Specifically, LC-NE activation reduced burst suppression in EEG and drove a rightward shift in peak EEG frequency with reduced δ EEG power and increased θ EEG power, measures of cortical arousal. LC-NE activation also accelerated behavioral emergence from deep isoflurane anesthesia; this was prevented with β or α1 noradrenergic antagonists. Moreover, these adrenoreceptor antagonists alone were sufficient to markedly potentiate anesthetic duration when delivered centrally or peripherally. Induction of anesthesia also was retarded by LC-NE activation. Our results demonstrate that the LC-NE system strongly modulates the anesthetic state, and that changes in LC-NE neurotransmission alone can affect the emergence from isoflurane general anesthesia. Taken together, these findings extend our understanding of mechanisms underlying general anesthesia and cortical arousal, and have significant implications for optimizing the clinical safety and management of general anesthesia.
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Affiliation(s)
- Elena M. Vazey
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425
| | - Gary Aston-Jones
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425
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McCarren HS, Moore JT, Kelz MB. Assessing changes in volatile general anesthetic sensitivity of mice after local or systemic pharmacological intervention. J Vis Exp 2013:e51079. [PMID: 24192721 DOI: 10.3791/51079] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
One desirable endpoint of general anesthesia is the state of unconsciousness, also known as hypnosis. Defining the hypnotic state in animals is less straightforward than it is in human patients. A widely used behavioral surrogate for hypnosis in rodents is the loss of righting reflex (LORR), or the point at which the animal no longer responds to their innate instinct to avoid the vulnerability of dorsal recumbency. We have developed a system to assess LORR in 24 mice simultaneously while carefully controlling for potential confounds, including temperature fluctuations and varying gas flows. These chambers permit reliable assessment of anesthetic sensitivity as measured by latency to return of the righting reflex (RORR) following a fixed anesthetic exposure. Alternatively, using stepwise increases (or decreases) in anesthetic concentration, the chambers also enable determination of a population's sensitivity to induction (or emergence) as measured by EC50 and Hill slope. Finally, the controlled environmental chambers described here can be adapted for a variety of alternative uses, including inhaled delivery of other drugs, toxicology studies, and simultaneous real-time monitoring of vital signs.
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Affiliation(s)
- Hilary S McCarren
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania
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Sanders RD, Maze M. Take Off, Landing, and Fly Anesthesia. PLoS Genet 2013; 9:e1003788. [PMID: 24039612 PMCID: PMC3764188 DOI: 10.1371/journal.pgen.1003788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Robert D. Sanders
- Department of Anaesthesia and Surgical Outcomes Research Centre, University College London Hospital & Wellcome Department of Imaging Neuroscience, University College London, London, United Kingdom
- * E-mail: (RS); (MM)
| | - Mervyn Maze
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail: (RS); (MM)
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Enhanced tonic inhibition influences the hypnotic and amnestic actions of the intravenous anesthetics etomidate and propofol. J Neurosci 2013; 33:7264-73. [PMID: 23616535 DOI: 10.1523/jneurosci.5475-12.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Intravenous anesthetics exert a component of their actions via potentiating inhibitory neurotransmission mediated by γ-aminobutyric type-A receptors (GABAARs). Phasic and tonic inhibition is mediated by distinct populations of GABAARs, with the majority of phasic inhibition by subtypes composed of α1-3βγ2 subunits, whereas tonic inhibition is dependent on subtypes assembled from α4-6βδ subunits. To explore the contribution that these distinct forms of inhibition play in mediating intravenous anesthesia, we have used mice in which tyrosine residues 365/7 within the γ2 subunit are mutated to phenyalanines (Y365/7F). Here we demonstrate that this mutation leads to increased accumulation of the α4 subunit containing GABAARs in the thalamus and dentate gyrus of female Y365/7F but not male Y365/7F mice. Y365/7F mice exhibited a gender-specific enhancement of tonic inhibition in the dentate gyrus that was more sensitive to modulation by the anesthetic etomidate, together with a deficit in long-term potentiation. Consistent with this, female Y365/7F, but not male Y365/7F, mice exhibited a dramatic increase in the duration of etomidate- and propofol-mediated hypnosis. Moreover, the amnestic actions of etomidate were selectively potentiated in female Y365/7F mice. Collectively, these observations suggest that potentiation of tonic inhibition mediated by α4 subunit containing GABAARs contributes to the hypnotic and amnestic actions of the intravenous anesthetics, etomidate and propofol.
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Abstract
Anesthetics have been used in clinical practice for over a hundred years, yet their mechanisms of action remain poorly understood. One tempting hypothesis to explain their hypnotic properties posits that anesthetics exert a component of their effects by "hijacking" the endogenous arousal circuitry of the brain. Modulation of activity within sleep- and wake-related neuroanatomic systems could thus explain some of the varied effects produced by anesthetics. There has been a recent explosion of research into the neuroanatomic substrates affected by various anesthetics. In this review, we will highlight the relevant sleep architecture and systems and focus on studies over the past few years that implicate these sleep-related structures as targets of anesthetics. These studies highlight a promising area of investigation regarding the mechanisms of action of anesthetics and provide an important model for future study.
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