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Yamada R, Koike T, Nakakariya M, Kimura H. Orexin receptor 2 agonist activates diaphragm and genioglossus muscle through stimulating inspiratory neurons in the pre-Bötzinger complex, and phrenic and hypoglossal motoneurons in rodents. PLoS One 2024; 19:e0306099. [PMID: 38917189 PMCID: PMC11198781 DOI: 10.1371/journal.pone.0306099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 06/10/2024] [Indexed: 06/27/2024] Open
Abstract
Orexin-mediated stimulation of orexin receptors 1/2 (OX[1/2]R) may stimulate the diaphragm and genioglossus muscle via activation of inspiratory neurons in the pre-Bötzinger complex, which are critical for the generation of inspiratory rhythm, and phrenic and hypoglossal motoneurons. Herein, we assessed the effects of OX2R-selective agonists TAK-925 (danavorexton) and OX-201 on respiratory function. In in vitro electrophysiologic analyses using rat medullary slices, danavorexton and OX-201 showed tendency and significant effect, respectively, in increasing the frequency of inspiratory synaptic currents of inspiratory neurons in the pre-Bötzinger complex. In rat medullary slices, both danavorexton and OX-201 significantly increased the frequency of inspiratory synaptic currents of hypoglossal motoneurons. Danavorexton and OX-201 also showed significant effect and tendency, respectively, in increasing the frequency of burst activity recorded from the cervical (C3-C5) ventral root, which contains axons of phrenic motoneurons, in in vitro electrophysiologic analyses from rat isolated brainstem-spinal cord preparations. Electromyogram recordings revealed that intravenous administration of OX-201 increased burst frequency of the diaphragm and burst amplitude of the genioglossus muscle in isoflurane- and urethane-anesthetized rats, respectively. In whole-body plethysmography analyses, oral administration of OX-201 increased respiratory activity in free-moving mice. Overall, these results suggest that OX2R-selective agonists enhance respiratory function via activation of the diaphragm and genioglossus muscle through stimulation of inspiratory neurons in the pre-Bötzinger complex, and phrenic and hypoglossal motoneurons. OX2R-selective agonists could be promising drugs for various conditions with respiratory dysfunction.
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Affiliation(s)
- Ryuji Yamada
- Neuroscience Drug Discovery Unit, Research, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Tatsuki Koike
- Neuroscience Drug Discovery Unit, Research, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Masanori Nakakariya
- Drug Metabolism and Pharmacokinetics Laboratory, Research, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
| | - Haruhide Kimura
- Neuroscience Drug Discovery Unit, Research, Takeda Pharmaceutical Company Limited, Fujisawa, Kanagawa, Japan
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2
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Alvente S, Matteoli G, Miglioranza E, Zoccoli G, Bastianini S. How to study sleep apneas in mouse models of human pathology. J Neurosci Methods 2023; 395:109923. [PMID: 37459897 DOI: 10.1016/j.jneumeth.2023.109923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/28/2023] [Accepted: 07/13/2023] [Indexed: 07/22/2023]
Abstract
Sleep apnea, the most widespread sleep-related breathing disorder (SBD), consists of recurrent episodes of breathing cessation during sleep. This condition can be classified as either central (CSA) or obstructive (OSA) sleep apnea, with the latest being the most common and toxic. Due to the complexity of living organisms, animal models and, particularly, mice still represent an essential tool for the study of SBD. In the present review we first discuss the methodological pros and cons in the use of whole-body plethysmography to coupling respiratory and sleep measurements and to characterize CSA and OSA in mice; then, we draw an updated and objective picture of the methods used so far in the study of sleep apnea in mice. Most of the studies present in the literature used intermittent hypoxia to mimic OSA in mice and to investigate consequent pathological correlates. On the contrary, few studies using genetic manipulation or high-fat diets investigated the pathogenesis or potential treatments of sleep apnea. To date, mice lacking orexins, hemeoxygenase-2, monoamine oxidase A, Phox2b or Cdkl5 can be considered validated mouse models of sleep apnea. Moreover, genetically- or diet-induced obese mice, and mice recapitulating Down syndrome were proposed as OSA models. In conclusion, our review shows that despite the growing interest in the field and the need of new therapeutical approaches, technical complexity and inter-study variability strongly limit the availability of validated mouse of sleep apnea, which are essential in biomedical research.
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Affiliation(s)
- Sara Alvente
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Gabriele Matteoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Elena Miglioranza
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Giovanna Zoccoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
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3
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Gracioso Martins AM, Snider DB, Popowski KD, Schuchard KG, Tenorio M, Akunuri S, Wee J, Peters KJ, Jansson A, Shirwaiker R, Cheng K, Freytes DO, Cruse GP. Low-dose intrapulmonary drug delivery device for studies on next-generation therapeutics in mice. J Control Release 2023; 359:287-301. [PMID: 37301267 PMCID: PMC10527740 DOI: 10.1016/j.jconrel.2023.05.039] [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: 10/14/2022] [Revised: 05/16/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023]
Abstract
Although nebulizers have been developed for delivery of small molecules in human patients, no tunable device has been purpose-built for targeted delivery of modern large molecule and temperature-sensitive therapeutics to mice. Mice are used most of all species in biomedical research and have the highest number of induced models for human-relevant diseases and transgene models. Regulatory approval of large molecule therapeutics, including antibody therapies and modified RNA highlight the need for quantifiable dose delivery in mice to model human delivery, proof-of-concept studies, efficacy, and dose-response. To this end, we developed and characterized a tunable nebulization system composed of an ultrasonic transducer equipped with a mesh nebulizer fitted with a silicone restrictor plate modification to control the nebulization rate. We have identified the elements of design that influence the most critical factors to targeted delivery to the deep lungs of BALB/c mice. By comparing an in silico model of the mouse lung with experimental data, we were able to optimize and confirm the targeted delivery of over 99% of the initial volume to the deep portions of the mouse lung. The resulting nebulizer system provides targeted lung delivery efficiency far exceeding conventional nebulizers preventing waste of expensive biologics and large molecules during proof-of-concept and pre-clinical experiments involving mice. (Word Count =207).
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Affiliation(s)
- Ana Maria Gracioso Martins
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA
| | - Douglas B Snider
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine and Translational Research Training Program, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA
| | - Kristen D Popowski
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA
| | - Karl G Schuchard
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, NC, USA
| | - Matias Tenorio
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA
| | - Sandip Akunuri
- Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA
| | - Junghyun Wee
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Kara J Peters
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Anton Jansson
- Analytical Instrumentation Facility, Monteith Research Center, North Carolina State University, Raleigh, NC, USA
| | - Rohan Shirwaiker
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA; Edward P. Fitts Department of Industrial and Systems Engineering, North Carolina State University, Raleigh, NC, USA; Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, USA
| | - Ke Cheng
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA
| | - Donald O Freytes
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Joint Department of Biomedical Engineering, North Carolina State University & University of North Carolina-Chapel Hill, NC, USA
| | - Glenn P Cruse
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA.
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4
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Hammer M, Jung F, Brankačk J, Yanovsky Y, Tort ABL, Draguhn A. Respiration and rapid eye movement (
REM)
sleep substructure: short versus long episodes. J Sleep Res 2022; 32:e13777. [PMID: 36398708 DOI: 10.1111/jsr.13777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 09/11/2022] [Accepted: 10/18/2022] [Indexed: 11/19/2022]
Abstract
Rapid eye movement (REM) sleep in rodents is defined by the presence of theta rhythm in the absence of movement. The amplitude and frequency of theta oscillations have been used to distinguish between tonic and phasic REM sleep. However, tonic REM sleep has not been further subdivided, although characteristics of network oscillations such as cross-frequency coupling between theta and gamma vary within this sub-state. Recently, it has been shown that theta-gamma coupling depends on an optimal breathing rate of ~5 Hz. The frequency of breathing varies strongly throughout REM sleep, and the duration of single REM sleep episodes ranges from several seconds to minutes, whereby short episodes predominate. Here we studied the relation between breathing frequency, accelerometer activity, and the length of REM sleep periods. We found that small movements detected with three-dimensional accelerometry positively correlate with breathing rate. Interestingly, breathing is slow in short REM sleep episodes, while faster respiration regimes exclusively occur after a certain delay in longer REM sleep episodes. Thus, merging REM sleep episodes of different lengths will result in a predominance of slow respiration due to the higher occurrence of short REM sleep periods. Moreover, our results reveal that not only do phasic REM sleep epochs predominantly occur during long REM sleep episodes, but that the long episodes also have faster theta and higher gamma activity. These observations suggest that REM sleep can be further divided from a physiological point of view depending on its duration. Higher levels of arousal during REM sleep, indicated by higher breathing rates, can only be captured in long REM sleep episodes.
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Affiliation(s)
- Maximilian Hammer
- Department of Physiology and Pathophysiology University of Heidelberg Heidelberg Germany
| | - Felix Jung
- Department of Physiology and Pathophysiology University of Heidelberg Heidelberg Germany
- Department of Neuroscience Karolinska Institute Stockholm Sweden
| | - Jurij Brankačk
- Department of Physiology and Pathophysiology University of Heidelberg Heidelberg Germany
| | - Yevgenij Yanovsky
- Department of Physiology and Pathophysiology University of Heidelberg Heidelberg Germany
| | - Adriano B. L. Tort
- Brain Institute Federal University of Rio Grande do Norte Natal Rio Grande do Norte Brazil
| | - Andreas Draguhn
- Department of Physiology and Pathophysiology University of Heidelberg Heidelberg Germany
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Schreck MR, Zhuang L, Janke E, Moberly AH, Bhattarai JP, Gottfried JA, Wesson DW, Ma M. State-dependent olfactory processing in freely behaving mice. Cell Rep 2022; 38:110450. [PMID: 35235805 PMCID: PMC8958632 DOI: 10.1016/j.celrep.2022.110450] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 11/07/2021] [Accepted: 02/07/2022] [Indexed: 11/06/2022] Open
Abstract
Decreased responsiveness to sensory stimuli during sleep is presumably mediated via thalamic gating. Without an obligatory thalamic relay in the olfactory system, the anterior piriform cortex (APC) is suggested to be a gate in anesthetized states. However, olfactory processing in natural sleep states remains undetermined. Here, we simultaneously record local field potentials (LFPs) in hierarchical olfactory regions (olfactory bulb [OB], APC, and orbitofrontal cortex) while optogenetically activating olfactory sensory neurons, ensuring consistent peripheral inputs across states in behaving mice. Surprisingly, evoked LFPs in sleep states (both non-rapid eye movement [NREM] and rapid eye movement [REM]) are larger and contain greater gamma-band power and cross-region coherence (compared to wakefulness) throughout the olfactory pathway, suggesting the lack of a central gate. Single-unit recordings from the OB and APC reveal a higher percentage of responsive neurons during sleep with a higher incidence of suppressed firing. Additionally, nasal breathing is slower and shallower during sleep, suggesting a partial peripheral gating mechanism. Schreck et al. examine how the olfactory system responds to the same peripheral stimulus during natural sleep and wake in mice. Larger responses along the pathway during sleep suggest the lack of a central gate, but slower and shallower breathing may act as a partial peripheral gate to reduce olfactory input.
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Affiliation(s)
- Mary R Schreck
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
| | - Liujing Zhuang
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Emma Janke
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Andrew H Moberly
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Janardhan P Bhattarai
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jay A Gottfried
- Department of Psychology, University of Pennsylvania, School of Arts and Sciences; Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Daniel W Wesson
- Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA
| | - Minghong Ma
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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6
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Glovak ZT, Angel C, O'Brien CB, Baghdoyan HA, Lydic R. Buprenorphine differentially alters breathing among four congenic mouse lines as a function of dose, sex, and leptin status. Respir Physiol Neurobiol 2022; 297:103834. [PMID: 34954128 PMCID: PMC8810735 DOI: 10.1016/j.resp.2021.103834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 12/01/2021] [Accepted: 12/20/2021] [Indexed: 01/29/2023]
Abstract
The opioid buprenorphine alters breathing and the cytokine leptin stimulates breathing. Obesity increases the risk for respiratory disorders and can lead to leptin resistance. This study tested the hypothesis that buprenorphine causes dose-dependent changes in breathing that vary as a function of obesity, leptin status, and sex. Breathing measures were acquired from four congenic mouse lines: female and male wild type C57BL/6J (B6) mice, obese db/db and ob/ob mice with leptin dysfunction, and male B6 mice with diet-induced obesity. Mice were injected intraperitoneally with saline (control) and five doses of buprenorphine (0.1, 0.3, 1.0, 3.0, 10 mg/kg). Buprenorphine caused dose-dependent decreases in respiratory frequency while increasing tidal volume, minute ventilation, and respiratory duty cycle. The effects of buprenorphine varied significantly with leptin status and sex. Buprenorphine decreased minute ventilation variability in all mice. The present findings highlight leptin status as an important modulator of respiration and encourage future studies aiming to elucidate the mechanisms through which leptin status alters breathing.
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Affiliation(s)
- Zachary T Glovak
- Psychology, University of Tennessee, Knoxville, TN, 37996, United States
| | - Chelsea Angel
- Anesthesiology, University of Michigan Health System, Ann Arbor, MI, 48105, United States
| | | | - Helen A Baghdoyan
- Psychology, University of Tennessee, Knoxville, TN, 37996, United States; Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States
| | - Ralph Lydic
- Psychology, University of Tennessee, Knoxville, TN, 37996, United States; Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States.
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7
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Alkalosis-induced hypoventilation in cystic fibrosis: The importance of efficient renal adaptation. Proc Natl Acad Sci U S A 2022; 119:2116836119. [PMID: 35173044 PMCID: PMC8872776 DOI: 10.1073/pnas.2116836119] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2022] [Indexed: 11/18/2022] Open
Abstract
The lungs and kidneys are pivotal organs in the regulation of body acid-base homeostasis. In cystic fibrosis (CF), the impaired renal ability to excrete an excess amount of HCO3 - into the urine leads to metabolic alkalosis [P. Berg et al., J. Am. Soc. Nephrol. 31, 1711-1727 (2020); F. Al-Ghimlas, M. E. Faughnan, E. Tullis, Open Respir. Med. J. 6, 59-62 (2012)]. This is caused by defective HCO3 - secretion in the β-intercalated cells of the collecting duct that requires both the cystic fibrosis transmembrane conductance regulator (CFTR) and pendrin for normal function [P. Berg et al., J. Am. Soc. Nephrol. 31, 1711-1727 (2020)]. We studied the ventilatory consequences of acute oral base loading in normal, pendrin knockout (KO), and CFTR KO mice. In wild-type mice, oral base loading induced a dose-dependent metabolic alkalosis, fast urinary removal of base, and a moderate base load did not perturb ventilation. In contrast, CFTR and pendrin KO mice, which are unable to rapidly excrete excess base into the urine, developed a marked and transient depression of ventilation when subjected to the same base load. Therefore, swift renal base elimination in response to an acute oral base load is a necessary physiological function to avoid ventilatory depression. The transient urinary alkalization in the postprandial state is suggested to have evolved for proactive avoidance of hypoventilation. In CF, metabolic alkalosis may contribute to the commonly reduced lung function via a suppression of ventilatory drive.
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8
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Geuther B, Chen M, Galante RJ, Han O, Lian J, George J, Pack AI, Kumar V. High-throughput visual assessment of sleep stages in mice using machine learning. Sleep 2021; 45:6414386. [PMID: 34718812 DOI: 10.1093/sleep/zsab260] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES Sleep is an important biological process that is perturbed in numerous diseases, and assessment its substages currently requires implantation of electrodes to carry out electroencephalogram/electromyogram (EEG/EMG) analysis. Although accurate, this method comes at a high cost of invasive surgery and experts trained to score EEG/EMG data. Here, we leverage modern computer vision methods to directly classify sleep substages from video data. This bypasses the need for surgery and expert scoring, provides a path to high-throughput studies of sleep in mice. METHODS We collected synchronized high-resolution video and EEG/EMG data in 16 male C57BL/6J mice. We extracted features from the video that are time and frequency-based and used the human expert-scored EEG/EMG data to train a visual classifier. We investigated several classifiers and data augmentation methods. RESULTS Our visual sleep classifier proved to be highly accurate in classifying wake, non-rapid eye movement sleep (NREM), and rapid eye movement sleep (REM) states, and achieves an overall accuracy of 0.92 +/- 0.05 (mean +/- SD). We discover and genetically validate video features that correlate with breathing rates, and show low and high variability in NREM and REM sleep, respectively. Finally, we apply our methods to non-invasively detect that sleep stage disturbances induced by amphetamine administration. CONCLUSIONS We conclude that machine learning based visual classification of sleep is a viable alternative to EEG/EMG based scoring. Our results will enable non-invasive high-throughput sleep studies and will greatly reduce the barrier to screening mutant mice for abnormalities in sleep.
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Affiliation(s)
- Brian Geuther
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME
| | - Mandy Chen
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME
| | - Raymond J Galante
- University of Pennsylvania, John Miclot Professor of Medicine, Division of Sleep Medicine/Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA
| | - Owen Han
- University of Pennsylvania, John Miclot Professor of Medicine, Division of Sleep Medicine/Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA
| | - Jie Lian
- University of Pennsylvania, John Miclot Professor of Medicine, Division of Sleep Medicine/Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA
| | - Joshy George
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME
| | - Allan I Pack
- University of Pennsylvania, John Miclot Professor of Medicine, Division of Sleep Medicine/Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, 125 South 31st Street, Suite 2100, Philadelphia, PA
| | - Vivek Kumar
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME
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9
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Kuzmin VS, Potekhina VM, Odnoshivkina YG, Chelombitko MA, Fedorov AV, Averina OA, Borodkov AS, Shevtsova AA, Lovat ML, Petrov AM. Proarrhythmic atrial ectopy associated with heart sympathetic innervation dysfunctions is specific for murine B6CBAF1 hybrid strain. Life Sci 2020; 266:118887. [PMID: 33316264 DOI: 10.1016/j.lfs.2020.118887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 11/25/2020] [Accepted: 12/04/2020] [Indexed: 11/20/2022]
Abstract
A lot of animal models are developed with aim to advance in atrial fibrillation (AF) understanding. The hybrid B6CBAF1 mice are used extensively as a background to create manifestation of various diseases, however, their atrial electrophysiology, autonomic sympathetic innervation of the heart and potential for AF investigation is poorly characterized. In the present study we used ECG and microelectrode recordings from multicellular atrial preparations to reveal attributes of atrial electrical activity in B6CBAF1. Also, experiments with a fluorescent false monoamine neurotransmitter and glyoxylic acid-based staining were carried out to characterize functionally and morphologically catecholaminergic innervation of the B6CBAF1 atria. Atrial myocardium of B6CBAF1 is highly prone to ectopic automaticity and exhibits abnormal spontaneous action potential accompanied by multiple postdepolarizations that result in proarrhythmic triggered activity unlike two parental C57Bl/6 and CBA strains. In vivo experiments revealed that B6CBAF1 hybrids are more susceptible to the norepinephrine induced AF. Also, sympathetic nerve terminals are partially dysfunctional in B6CBAF1 revealing lower ability to accumulate and release neurotransmitters unlike two parental strains. The analysis of the heart rate variability revealed suppressed sympathetic component of the autonomic heart control in B6CBAF1. The organization of sympathetic innervation is very similar morphologically in all three murine strains however the abundance of non-bifurcated catecholamine-positive fibers in B6CBAF1 was increased. These results suggest that B6CBAF1 mice exhibit enhanced intrinsic atrial proarrhythmicity, while the abnormalities of sympathetic neurotransmitter cycling probably underlie disturbed autonomic heart control.
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Affiliation(s)
- Vlad S Kuzmin
- Lomonosov Moscow State University, Biological Faculty, Department of Human and Animal Physiology, Leninskie gory 1, building 12, 119991 Moscow, Russia; Pirogov Russian National Research Medical University (RNRMU), Ostrovitjanova 1, 117997 Moscow, Russia
| | - Viktoriia M Potekhina
- Lomonosov Moscow State University, Biological Faculty, Department of Human and Animal Physiology, Leninskie gory 1, building 12, 119991 Moscow, Russia.
| | | | - Maria A Chelombitko
- The A.N. Belozersky Institute of Physico-Chemical Biology, MSU, Moscow, Russia
| | - Artem V Fedorov
- Lomonosov Moscow State University, Biological Faculty, Department of Human and Animal Physiology, Leninskie gory 1, building 12, 119991 Moscow, Russia
| | - Olga A Averina
- The A.N. Belozersky Institute of Physico-Chemical Biology, MSU, Moscow, Russia; Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, Russia
| | - Alexey S Borodkov
- Vernadsky Institute of Geochemistry and Analytical Chemistry of Russian Academу of Sciences, Moscow, Russia
| | - Anna A Shevtsova
- Lomonosov Moscow State University, Faculty of Biology, Department of Genetics, Moscow, Russia
| | - Maxim L Lovat
- Lomonosov Moscow State University, Biological Faculty, Department of Human and Animal Physiology, Leninskie gory 1, building 12, 119991 Moscow, Russia
| | - Alexey M Petrov
- Institute of Neuroscience, Kazan State Medial University, Kazan, Russia; Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
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10
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Kloefkorn H, Aiani LM, Lakhani A, Nagesh S, Moss A, Goolsby W, Rehg JM, Pedersen NP, Hochman S. Noninvasive three-state sleep-wake staging in mice using electric field sensors. J Neurosci Methods 2020; 344:108834. [PMID: 32619585 PMCID: PMC7454007 DOI: 10.1016/j.jneumeth.2020.108834] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/22/2020] [Accepted: 06/26/2020] [Indexed: 11/22/2022]
Abstract
STUDY OBJECTIVE Validate a novel method for sleep-wake staging in mice using noninvasive electric field (EF) sensors. METHODS Mice were implanted with electroencephalogram (EEG) and electromyogram (EMG) electrodes and housed individually. Noninvasive EF sensors were attached to the exterior of each chamber to record respiration and other movement simultaneously with EEG, EMG, and video. A sleep-wake scoring method based on EF sensor data was developed with reference to EEG/EMG and then validated by three expert scorers. Additionally, novice scorers without sleep-wake scoring experience were self-trained to score sleep using only the EF sensor data, and results were compared to those from expert scorers. Lastly, ability to capture three-state sleep-wake staging with EF sensors attached to traditional mouse home-cages was tested. RESULTS EF sensors quantified wake, rapid eye movement (REM) sleep, and non-REM sleep with high agreement (>93%) and comparable inter- and intra-scorer error as EEG/EMG. Novice scorers successfully learned sleep-wake scoring using only EF sensor data and scoring criteria, and achieved high agreement with expert scorers (>91%). When applied to traditional home-cages, EF sensors enabled classification of three-state (wake, NREM and REM) sleep-wake independent of EEG/EMG. CONCLUSIONS EF sensors score three-state sleep-wake architecture with high agreement to conventional EEG/EMG sleep-wake scoring 1) without invasive surgery, 2) from outside the home-cage, and 3) and without requiring specialized training or equipment. EF sensors provide an alternative method to assess rodent sleep for animal models and research laboratories in which EEG/EMG is not possible or where noninvasive approaches are preferred.
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Affiliation(s)
- H Kloefkorn
- Department of Physiology, School of Medicine, Emory University, Atlanta, GA, USA.
| | - L M Aiani
- Department of Neurology, School of Medicine, Emory University, Atlanta, GA, USA
| | - A Lakhani
- Department of Physiology, School of Medicine, Emory University, Atlanta, GA, USA
| | - S Nagesh
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - A Moss
- Department of Physiology, School of Medicine, Emory University, Atlanta, GA, USA
| | - W Goolsby
- Department of Physiology, School of Medicine, Emory University, Atlanta, GA, USA
| | - J M Rehg
- School of Interactive Computing, Georgia Institute of Technology, Atlanta, GA, USA
| | - N P Pedersen
- Department of Neurology, School of Medicine, Emory University, Atlanta, GA, USA.
| | - S Hochman
- Department of Physiology, School of Medicine, Emory University, Atlanta, GA, USA
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11
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Receno CN, Cunningham CM, Eassa BE, Purdy R, DeRuisseau LR. Method to Obtain Pattern of Breathing in Senescent Mice through Unrestrained Barometric Plethysmography. J Vis Exp 2020. [PMID: 32420981 DOI: 10.3791/59393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Unrestrained barometric plethysmography (UBP) is a method for quantifying the pattern of breathing in mice, where breathing frequency, tidal volume, and minute ventilation are routinely reported. Moreover, information can be collected regarding the neural output of breathing, including the existence of central apneas and augmented breaths. An important consideration for UBP is obtaining a breathing segment with a minimal impact of anxious or active behaviors, to elucidate the response to breathing challenges. Here, we present a protocol that allows for short, quiet baselines to be obtained in aged mice, comparable to waiting for longer bouts of quiet breathing. The use of shorter time segments is valuable, as some strains of mice may be increasingly excitable or anxious, and longer periods of quiet breathing may not be achieved within a reasonable timeframe. We placed 22 month-old mice in a UBP chamber and compared four 15 s quiet breathing segments between minutes 60-120 to a longer 10 min quiet breathing period that took 2-3 h to acquire. We also obtained counts of central apneas and augmented breaths prior to the quiet breathing segments, following a 30 min familiarization period. We show that 10 min of quiet breathing is comparable to using a much shorter 15 s duration. Additionally, the time leading up to these 15 s quiet breathing segments can be used to gather data regarding apneas of central origin. This protocol allows investigators to collect pattern-of-breathing data in a set amount of time and makes quiet baseline measures feasible for mice that may exhibit increased amounts of excitable behavior. The UBP methodology itself provides a useful and noninvasive way to collect pattern-of-breathing data and allows for mice to be tested over several time points.
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Barros D, García-Río F. Obstructive sleep apnea and dyslipidemia: from animal models to clinical evidence. Sleep 2020; 42:5204276. [PMID: 30476296 DOI: 10.1093/sleep/zsy236] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 10/02/2018] [Accepted: 11/22/2018] [Indexed: 01/11/2023] Open
Abstract
Lipid metabolism deregulation constitutes the pathogenic basis for the development of atherosclerosis and justifies a high incidence of cardiovascular-related morbidity and mortality. Some data suggest that dyslipidemia may be associated with sleep-disordered breathing, mainly obstructive sleep apnea (OSA), due to alterations in fundamental biochemical processes, such as intermittent hypoxia (IH). The aim of this systematic review was to identify and critically evaluate the current evidence supporting the existence of a possible relationship between OSA and alterations in lipid metabolism. Much evidence shows that, during the fasting state, OSA and IH increase lipid delivery from the adipose tissue to the liver through an up-regulation of the sterol regulatory element-binding protein-1 and stearoyl-CoA desaturase-1, increasing the synthesis of cholesterol esters and triglycerides. In the postprandial state, lipoprotein clearance is delayed due to lower lipoprotein lipase activity, probably secondary to IH-up-regulation of angiopoietin-like protein 4 and decreased activity of the peroxisome proliferator-activated receptor alpha. Moreover, oxidative stress can generate dysfunctional oxidized lipids and reduce the capacity of high-density lipoproteins (HDL) to prevent low-density lipoprotein (LDL) oxidation. In the clinical field, several observational studies and a meta-regression analysis support the existence of a link between OSA and dyslipidemia. Although there is evidence of improved lipid profile after apnea-hypopnea suppression with continuous positive airway pressure (CPAP), the majority of the data come from observational studies. In contrast, randomized controlled trials evaluating the effects of CPAP on lipid metabolism present inconclusive results and two meta-analyses provide contradictory evidence.
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Affiliation(s)
- David Barros
- Servicio de Neumología, Hospital Montecelo, Pontevedra, Spain
| | - Francisco García-Río
- Servicio de Neumología, Hospital Universitario La Paz-IdiPAZ, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain.,Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
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13
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Taming the oscillatory zoo in the hippocampus and neo-cortex: a review of the commentary of Lockmann and Tort on Roy et al. Brain Struct Funct 2017; 223:5-9. [PMID: 29222725 DOI: 10.1007/s00429-017-1569-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 11/10/2017] [Indexed: 12/16/2022]
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14
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Meier D, Collet TH, Locatelli I, Cornuz J, Kayser B, Simel DL, Sartori C. Does This Patient Have Acute Mountain Sickness?: The Rational Clinical Examination Systematic Review. JAMA 2017; 318:1810-1819. [PMID: 29136449 DOI: 10.1001/jama.2017.16192] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
IMPORTANCE Acute mountain sickness (AMS) affects more than 25% of individuals ascending to 3500 m (11 500 ft) and more than 50% of those above 6000 m (19 700 ft). AMS may progress from nonspecific symptoms to life-threatening high-altitude cerebral edema in less than 1% of patients. It is not clear how to best diagnose AMS. OBJECTIVE To systematically review studies assessing the accuracy of AMS diagnostic instruments, including the visual analog scale (VAS) score, which quantifies the overall feeling of sickness at altitude (VAS[O]; various thresholds), Acute Mountain Sickness-Cerebral score (AMS-C; ≥0.7 indicates AMS), and the clinical functional score (CFS; ≥2 indicates AMS) compared with the Lake Louise Questionnaire Score (LLQS; score of ≥5). DATA EXTRACTION AND SYNTHESIS Searches of MEDLINE and EMBASE from inception to May 2017 identified 1245 publications of which 91 were suitable for prevalence analysis (66 944 participants) and 14 compared at least 2 instruments (1858 participants) using a score of 5 or greater on the LLQS as a reference standard. To determine the prevalence of AMS for establishing the pretest probability of AMS, a random-effects meta-regression was performed based on the reported prevalence of AMS as a function of altitude. MAIN OUTCOMES AND MEASURES AMS prevalence, likelihood ratios (LRs), sensitivity, and specificity of screening instruments. RESULTS The final analysis included 91 articles (comprising 66 944 study participants). Altitude predicted AMS and accounted for 28% of heterogeneity between studies. For each 1000-m (3300-ft) increase in altitude above 2500 m (8200 ft), AMS prevalence increased 13% (95% CI, 9.5%-17%). Testing characteristics were similar for VAS(O), AMS-C, and CFS vs a score of 5 or greater on the LLQS (positive LRs: range, 3.2-8.2; P = .22 for comparisons; specificity range, 67%-92%; negative LRs: range, 0.30-0.36; P = .50 for comparisons; sensitivity range, 67%-82%). The CFS asks a single question: "overall if you had any symptoms, how did they affect your activity (ordinal scale 0-3)?" For CFS, moderate to severe reduction in daily activities had a positive LR of 3.2 (95% CI, 1.4-7.2) and specificity of 67% (95% CI, 37%-97%); no reduction to mild reduction in activities had a negative LR of 0.30 (95% CI, 0.22-0.39) and sensitivity of 82% (95% CI, 77%-87%). CONCLUSIONS AND RELEVANCE The prevalence of acute mountain sickness increases with higher altitudes. The visual analog scale for the overall feeling of sickness at altitude, Acute Mountain Sickness-Cerebral, and clinical functional score perform similarly to the Lake Louise Questionnaire Score using a score of 5 or greater as a reference standard. In clinical and travel settings, the clinical functional score is the simplest instrument to use. Clinicians evaluating high-altitude travelers who report moderate to severe limitations in activities of daily living (clinical functional score ≥2) should use the Lake Louise Questionnaire Score to assess the severity of acute mountain sickness.
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Affiliation(s)
- David Meier
- Service of Internal Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Tinh-Hai Collet
- Service of Endocrinology, Diabetes, and Metabolism, Lausanne University Hospital, Lausanne, Switzerland
- Ambulatory Care and Community Medicine, University of Lausanne; Lausanne, Switzerland
| | - Isabella Locatelli
- Ambulatory Care and Community Medicine, University of Lausanne; Lausanne, Switzerland
| | - Jacques Cornuz
- Ambulatory Care and Community Medicine, University of Lausanne; Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
| | - David L Simel
- Department of Medicine, Durham VA Medical Center, Durham, North Carolina
- Department of Medicine, Duke University Health System, Durham, North Carolina
| | - Claudio Sartori
- Service of Internal Medicine, Lausanne University Hospital, Lausanne, Switzerland
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15
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Purnell BS, Hajek MA, Buchanan GF. Time-of-day influences on respiratory sequelae following maximal electroshock-induced seizures in mice. J Neurophysiol 2017; 118:2592-2600. [PMID: 28794189 PMCID: PMC5668461 DOI: 10.1152/jn.00039.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 11/22/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in refractory epilepsy patients. Although specific mechanisms underlying SUDEP are not well understood, evidence suggests most SUDEP occurs due to seizure-induced respiratory arrest. SUDEP also tends to happen at night. Although this may be due to circumstances in which humans find themselves at night, such as being alone without supervision or sleeping prone, or to independent influences of sleep state, there are a number of reasons why the night (i.e., circadian influences) could be an independent risk factor for SUDEP. We explored this possibility. Adult male WT mice were instrumented for EEG, EMG, and EKG recording and subjected to maximal electroshock (MES) seizures during wakefulness, non-rapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep during the nighttime/dark phase. These data were compared with data collected following seizures induced during the daytime/light phase. Seizures induced during the nighttime were similar in severity and duration to those induced during the daytime; however, seizures induced during the nighttime were associated with a lesser degree of respiratory dysregulation and postictal EEG suppression. Seizures induced during REM sleep during the nighttime were universally fatal, as is seen when seizures are induced during REM during the daytime. Taken together, these data implicate a role for time of day in influencing the physiological consequences of seizures that may contribute to seizure-induced death.NEW & NOTEWORTHY Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. SUDEP frequently occurs during the night, which has been attributed to an effect of sleep. We have shown that sleep state does indeed influence survival following a seizure. That SUDEP occurs during the night could also implicate a circadian influence. In this study we found that time of day independently affects the physiological consequences of seizures.
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Affiliation(s)
- Benton S Purnell
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Michael A Hajek
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut
| | - Gordon F Buchanan
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa Carver College of Medicine, Iowa City, Iowa;
- Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, Iowa; and
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut
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16
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Abstract
Sleep apnea, which is the periodic cessation of breathing during sleep, is a major health problem affecting over 10 million people in the United States and is associated with several sequelae, including hypertension and stroke. Clinical studies suggest that abnormal carotid body (CB) activity may be a driver of sleep apnea. Because gaseous molecules are important determinants of CB activity, aberrations in their signaling could lead to sleep apnea. Here, we report that mice deficient in heme oxygenase-2 (HO-2), which generates the gaseous molecule carbon monoxide (CO), exhibit sleep apnea characterized by high apnea and hypopnea indices during rapid eye movement (REM) sleep. Similar high apnea and hypopnea indices were also noted in prehypertensive spontaneously hypertensive (SH) rats, which are known to exhibit CB hyperactivity. We identified the gaseous molecule hydrogen sulfide (H2S) as the major effector molecule driving apneas. Genetic ablation of the H2S-synthesizing enzyme cystathionine-γ-lyase (CSE) normalized breathing in HO-2-/- mice. Pharmacologic inhibition of CSE with l-propargyl glycine prevented apneas in both HO-2-/- mice and SH rats. These observations demonstrate that dysregulated CO and H2S signaling in the CB leads to apneas and suggest that CSE inhibition may be a useful therapeutic intervention for preventing CB-driven sleep apnea.
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17
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Olfactory Bulb Field Potentials and Respiration in Sleep-Wake States of Mice. Neural Plast 2016; 2016:4570831. [PMID: 27247803 PMCID: PMC4877487 DOI: 10.1155/2016/4570831] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/13/2016] [Accepted: 04/20/2016] [Indexed: 12/11/2022] Open
Abstract
It is well established that local field potentials (LFP) in the rodent olfactory bulb (OB) follow respiration. This respiration-related rhythm (RR) in OB depends on nasal air flow, indicating that it is conveyed by sensory inputs from the nasal epithelium. Recently RR was found outside the olfactory system, suggesting that it plays a role in organizing distributed network activity. It is therefore important to measure RR and to delineate it from endogenous electrical rhythms like theta which cover similar frequency bands in small rodents. In order to validate such measurements in freely behaving mice, we compared rhythmic LFP in the OB with two respiration-related biophysical parameters: whole-body plethysmography (PG) and nasal temperature (thermocouple; TC). During waking, all three signals reflected respiration with similar reliability. Peak power of RR in OB decreased with increasing respiration rate whereas power of PG increased. During NREM sleep, respiration-related TC signals disappeared and large amplitude slow waves frequently concealed RR in OB. In this situation, PG provided a reliable signal while breathing-related rhythms in TC and OB returned only during microarousals. In summary, local field potentials in the olfactory bulb do reliably reflect respiratory rhythm during wakefulness and REM sleep but not during NREM sleep.
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18
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Liu N, Adams V, Kalmar L, Ladlow J, Sargan D. Whole-Body Barometric Plethysmography Characterizes Upper Airway Obstruction in 3 Brachycephalic Breeds of Dogs. J Vet Intern Med 2016; 30:853-65. [PMID: 27159898 PMCID: PMC4913582 DOI: 10.1111/jvim.13933] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 02/09/2016] [Accepted: 02/29/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND A novel test using whole-body barometric plethysmography (WBBP) was developed recently to diagnose brachycephalic obstructive airway syndrome (BOAS) in unsedated French bulldogs. HYPOTHESIS/OBJECTIVES The hypotheses of this study were: (1) respiratory characteristics are different between healthy nonbrachycephalic dogs and brachycephalic dogs; and among pugs, French bulldogs, and bulldogs; and (2) obesity and stenotic nares are risk factors for BOAS. The main objective was to establish a diagnostic test for BOAS in these 3 breeds. ANIMALS A total of 266 brachycephalic dogs (100 pugs, 100 French bulldogs, and 66 bulldogs) and 28 nonbrachycephalic dogs. METHODS Prospective study. Exercise tolerance tests with respiratory functional grading, and WBBP were performed on all dogs. Data from WBBP were associated with functional grades to train quadratic discriminant analysis tools to assign dogs to BOAS+ and BOAS- groups. A BOAS index (0-100%) was calculated for each dog. Receiver operating characteristic (ROC) curves were used to evaluate classification ability. RESULTS Minute volume was decreased significantly in asymptomatic pugs (P = .009), French bulldogs (P = .026), and bulldogs (P < .0001) when compared to nonbrachycephalic controls. Respiratory characteristics were different among breeds and affected dogs had a significant increase in trace variation. The BOAS index predicted BOAS status for each breed with 94-97% (95% confidence interval [CI], 88.9-100%) accuracy (area under the ROC curve). Both obesity (P = .04) and stenotic nares (P = .004) were significantly associated with BOAS. CONCLUSIONS AND CLINICAL IMPORTANCE The WBBP can be used as a clinical tool to diagnose BOAS noninvasively and objectively.
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Affiliation(s)
- N‐C. Liu
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | | | - L. Kalmar
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - J.F. Ladlow
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
| | - D.R. Sargan
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
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19
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Hajek MA, Buchanan GF. Influence of vigilance state on physiological consequences of seizures and seizure-induced death in mice. J Neurophysiol 2016; 115:2286-93. [PMID: 26888097 DOI: 10.1152/jn.00011.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/13/2016] [Indexed: 12/31/2022] Open
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. SUDEP occurs more commonly during nighttime sleep. The details of why SUDEP occurs at night are not well understood. Understanding why SUDEP occurs at night during sleep might help to better understand why SUDEP occurs at all and hasten development of preventive strategies. Here we aimed to understand circumstances causing seizures that occur during sleep to result in death. Groups of 12 adult male mice were instrumented for EEG, EMG, and EKG recording and subjected to seizure induction via maximal electroshock (MES) during wakefulness, nonrapid eye movement (NREM) sleep, and rapid eye movement (REM) sleep. Seizure inductions were performed with concomitant EEG, EMG, and EKG recording and breathing assessment via whole body plethysmography. Seizures induced via MES during sleep were associated with more profound respiratory suppression and were more likely to result in death. Despite REM sleep being a time when seizures do not typically occur spontaneously, when seizures were forced to occur during REM sleep, they were invariably fatal in this model. An examination of baseline breathing revealed that mice that died following a seizure had increased baseline respiratory rate variability compared with those that did not die. These data demonstrate that sleep, especially REM sleep, can be a dangerous time for a seizure to occur. These data also demonstrate that there may be baseline respiratory abnormalities that can predict which individuals have higher risk for seizure-induced death.
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Affiliation(s)
- Michael A Hajek
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut
| | - Gordon F Buchanan
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut; Veterans Affairs Medical Center, West Haven, Connecticut; and Department of Neurology, University of Iowa Carver College of Medicine, Iowa City, Iowa
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20
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Yaghouby F, Donohue KD, O'Hara BF, Sunderam S. Noninvasive dissection of mouse sleep using a piezoelectric motion sensor. J Neurosci Methods 2016; 259:90-100. [PMID: 26582569 PMCID: PMC4715949 DOI: 10.1016/j.jneumeth.2015.11.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/01/2015] [Accepted: 11/04/2015] [Indexed: 10/22/2022]
Abstract
BACKGROUND Changes in autonomic control cause regular breathing during NREM sleep to fluctuate during REM. Piezoelectric cage-floor sensors have been used to successfully discriminate sleep and wake states in mice based on signal features related to respiration and other movements. This study presents a classifier for noninvasively classifying REM and NREM using a piezoelectric sensor. NEW METHOD Vigilance state was scored manually in 4-s epochs for 24-h EEG/EMG recordings in 20 mice. An unsupervised classifier clustered piezoelectric signal features quantifying movement and respiration into three states: one active; and two inactive with regular and irregular breathing, respectively. These states were hypothesized to correspond to Wake, NREM, and REM, respectively. States predicted by the classifier were compared against manual EEG/EMG scores to test this hypothesis. RESULTS Using only piezoelectric signal features, an unsupervised classifier distinguished Wake with high (89% sensitivity, 96% specificity) and REM with moderate (73% sensitivity, 75% specificity) accuracy, but NREM with poor sensitivity (51%) and high specificity (96%). The classifier sometimes confused light NREM sleep - characterized by irregular breathing and moderate delta EEG power - with REM. A supervised classifier improved sensitivities to 90, 81, and 67% and all specificities to over 90% for Wake, NREM, and REM, respectively. COMPARISON WITH EXISTING METHODS Unlike most actigraphic techniques, which only differentiate sleep from wake, the proposed piezoelectric method further dissects sleep based on breathing regularity into states strongly correlated with REM and NREM. CONCLUSIONS This approach could facilitate large-sample screening for genes influencing different sleep traits, besides drug studies or other manipulations.
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Affiliation(s)
- Farid Yaghouby
- Department of Biomedical Engineering, University of Kentucky, 143 Graham Ave., Lexington, KY 40506-0108, United States
| | - Kevin D Donohue
- Electrical and Computer Engineering, University of Kentucky, Lexington, KY, United States
| | - Bruce F O'Hara
- Department of Biology, University of Kentucky, Lexington, KY, United States
| | - Sridhar Sunderam
- Department of Biomedical Engineering, University of Kentucky, 143 Graham Ave., Lexington, KY 40506-0108, United States.
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21
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Drager LF, Polotsky VY, O'Donnell CP, Cravo SL, Lorenzi-Filho G, Machado BH. Translational approaches to understanding metabolic dysfunction and cardiovascular consequences of obstructive sleep apnea. Am J Physiol Heart Circ Physiol 2015; 309:H1101-11. [PMID: 26232233 DOI: 10.1152/ajpheart.00094.2015] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/22/2015] [Indexed: 12/17/2022]
Abstract
Obstructive sleep apnea (OSA) is known to be independently associated with several cardiovascular diseases including hypertension, myocardial infarction, and stroke. To determine how OSA can increase cardiovascular risk, animal models have been developed to explore the underlying mechanisms and the cellular and end-organ targets of the predominant pathophysiological disturbance in OSA-intermittent hypoxia. Despite several limitations in translating data from animal models to the clinical arena, significant progress has been made in our understanding of how OSA confers increased cardiovascular risk. It is clear now that the hypoxic stress associated with OSA can elicit a broad spectrum of pathological systemic events including sympathetic activation, systemic inflammation, impaired glucose and lipid metabolism, and endothelial dysfunction, among others. This review provides an update of the basic, clinical, and translational advances in our understanding of the metabolic dysfunction and cardiovascular consequences of OSA and highlights the most recent findings and perspectives in the field.
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Affiliation(s)
- Luciano F Drager
- Hypertension Unit, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil; Hypertension Unit, Renal Division, University of São Paulo Medical School, São Paulo, Brazil;
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Christopher P O'Donnell
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Sergio L Cravo
- Department of Physiology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, Brazil
| | - Geraldo Lorenzi-Filho
- Sleep Laboratory, Pulmonary Division, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil; and
| | - Benedito H Machado
- Department of Physiology, School of Medicine of Ribeirao Preto, University of São Paulo, São Paulo, Brazil
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22
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Mang GM, Nicod J, Emmenegger Y, Donohue KD, O'Hara BF, Franken P. Evaluation of a piezoelectric system as an alternative to electroencephalogram/ electromyogram recordings in mouse sleep studies. Sleep 2014; 37:1383-92. [PMID: 25083019 DOI: 10.5665/sleep.3936] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Traditionally, sleep studies in mammals are performed using electroencephalogram/electromyogram (EEG/EMG) recordings to determine sleep-wake state. In laboratory animals, this requires surgery and recovery time and causes discomfort to the animal. In this study, we evaluated the performance of an alternative, noninvasive approach utilizing piezoelectric films to determine sleep and wakefulness in mice by simultaneous EEG/EMG recordings. The piezoelectric films detect the animal's movements with high sensitivity and the regularity of the piezo output signal, related to the regular breathing movements characteristic of sleep, serves to automatically determine sleep. Although the system is commercially available (Signal Solutions LLC, Lexington, KY), this is the first statistical validation of various aspects of sleep. DESIGN EEG/EMG and piezo signals were recorded simultaneously during 48 h. SETTING Mouse sleep laboratory. PARTICIPANTS Nine male and nine female CFW outbred mice. INTERVENTIONS EEG/EMG surgery. MEASUREMENTS AND RESULTS The results showed a high correspondence between EEG/EMG-determined and piezo-determined total sleep time and the distribution of sleep over a 48-h baseline recording with 18 mice. Moreover, the piezo system was capable of assessing sleep quality (i.e., sleep consolidation) and interesting observations at transitions to and from rapid eye movement sleep were made that could be exploited in the future to also distinguish the two sleep states. CONCLUSIONS The piezo system proved to be a reliable alternative to electroencephalogram/electromyogram recording in the mouse and will be useful for first-pass, large-scale sleep screens for genetic or pharmacological studies. CITATION Mang GM, Nicod J, Emmenegger Y, Donohue KD, O'Hara BF, Franken P. Evaluation of a piezoelectric system as an alternative to electroencephalogram/electromyogram recordings in mouse sleep studies.
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Affiliation(s)
- Géraldine M Mang
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Jérôme Nicod
- The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Yann Emmenegger
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Kevin D Donohue
- Electrical and Computer Engineering Department, University of Kentucky, Lexington, KY ; Signal Solutions, LLC, Lexington, KY
| | - Bruce F O'Hara
- Signal Solutions, LLC, Lexington, KY ; Department of Biology, University of Kentucky, Lexington, KY
| | - Paul Franken
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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23
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Moore MW, Akladious A, Hu Y, Azzam S, Feng P, Strohl KP. Effects of orexin 2 receptor activation on apnea in the C57BL/6J mouse. Respir Physiol Neurobiol 2014; 200:118-25. [PMID: 24929062 DOI: 10.1016/j.resp.2014.03.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/11/2014] [Accepted: 03/31/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND The hypothesis was that an orexin 2 receptor (OX2R) agonist would prevent sleep-related disordered breathing. METHODS In C57BL/6J (B6) mice, body plethysmography was performed with and without EEG monitoring of state (wakefulness, NREM and REM sleep). Outcome was apnea rate/h during sleep-wake states at baseline and with an intracerebroventricular administration of vehicle, 4 nMol of agonist OB(DL), and 4 nMol of an antagonist, TCS OX2 29. RESULTS A significant reduction (p=0.035, f=2.99) in apneas/hour occurred, especially with the agonist. Expressed as a function of the change from baseline, there was a significant difference among groups in Wake (p=0.03, f=3.8), NREM (p=0.003, f=6.98) and REM (p=0.03, f=3.92) with the agonist reducing the rate of apneas during sleep from 29.7±4.7 (M±SEM) to 7.3±2.4 during sleep (p=0.001). There was also a reduction in apneas during wakefulness. Administration of the antagonist did not increase event rate over baseline levels. CONCLUSIONS The B6 mouse is a preclinical model of wake-and sleep-disordered breathing, and the orexin receptor agonist at a dose of 4 nMol given intracerebroventricularly will reduce events in sleep and also wakefulness.
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Affiliation(s)
- Michael W Moore
- Louis Stokes Cleveland DVA Medical Center, Cleveland, OH, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, UH Case Medical Center, Cleveland, OH 44016, United States
| | - Afaf Akladious
- Louis Stokes Cleveland DVA Medical Center, Cleveland, OH, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, UH Case Medical Center, Cleveland, OH 44016, United States
| | - Yufen Hu
- Louis Stokes Cleveland DVA Medical Center, Cleveland, OH, United States; Neogene Biosciences LLC, Cleveland, OH, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, UH Case Medical Center, Cleveland, OH 44016, United States
| | - Sausan Azzam
- Louis Stokes Cleveland DVA Medical Center, Cleveland, OH, United States; Case Western Reserve University, Cleveland, OH, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, UH Case Medical Center, Cleveland, OH 44016, United States
| | - Pingfu Feng
- Louis Stokes Cleveland DVA Medical Center, Cleveland, OH, United States; Neogene Biosciences LLC, Cleveland, OH, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, UH Case Medical Center, Cleveland, OH 44016, United States
| | - Kingman P Strohl
- Louis Stokes Cleveland DVA Medical Center, Cleveland, OH, United States; Case Western Reserve University, Cleveland, OH, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, UH Case Medical Center, Cleveland, OH 44016, United States.
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McShane BB, Jensen ST, Pack AI, Wyner AJ. Statistical Learning with Time Series Dependence: An Application to Scoring Sleep in Mice. J Am Stat Assoc 2013; 108:1147-1162. [PMID: 24504359 DOI: 10.1080/01621459.2013.779838] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We develop methodology which combines statistical learning methods with generalized Markov models, thereby enhancing the former to account for time series dependence. Our methodology can accommodate very general and very long-term time dependence structures in an easily estimable and computationally tractable fashion. We apply our methodology to the scoring of sleep behavior in mice. As currently used methods are expensive, invasive, and labor intensive, there is considerable interest in high-throughput automated systems which would allow many mice to be scored cheaply and quickly. Previous efforts have been able to differentiate sleep from wakefulness, but they are unable to differentiate the rare and important state of REM sleep from non-REM sleep. Key difficulties in detecting REM are that (i) REM is much rarer than non-REM and wakefulness, (ii) REM looks similar to non-REM in terms of the observed covariates, (iii) the data are noisy, and (iv) the data contain strong time dependence structures crucial for differentiating REM from non-REM. Our new approach (i) shows improved differentiation of REM from non-REM sleep and (ii) accurately estimates aggregate quantities of sleep in our application to video-based sleep scoring of mice.
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Affiliation(s)
| | | | - Allan I Pack
- Center for Sleep and Circadian Neurobiology, University of Pennsylvania
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25
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Pagliardini S, Gosgnach S, Dickson CT. Spontaneous sleep-like brain state alternations and breathing characteristics in urethane anesthetized mice. PLoS One 2013; 8:e70411. [PMID: 23936201 PMCID: PMC3728022 DOI: 10.1371/journal.pone.0070411] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 06/19/2013] [Indexed: 11/19/2022] Open
Abstract
Brain state alternations resembling those of sleep spontaneously occur in rats under urethane anesthesia and they are closely linked with sleep-like respiratory changes. Although rats are a common model for both sleep and respiratory physiology, we sought to determine if similar brain state and respiratory changes occur in mice under urethane. We made local field potential recordings from the hippocampus and measured respiratory activity by means of EMG recordings in intercostal, genioglossus, and abdominal muscles. Similar to results in adult rats, urethane anesthetized mice displayed quasi-periodic spontaneous forebrain state alternations between deactivated patterns resembling slow wave sleep (SWS) and activated patterns resembling rapid eye movement (REM) sleep. These alternations were associated with an increase in breathing rate, respiratory variability, a depression of inspiratory related activity in genioglossus muscle and an increase in expiratory-related abdominal muscle activity when comparing deactivated (SWS-like) to activated (REM-like) states. These results demonstrate that urethane anesthesia consistently induces sleep-like brain state alternations and correlated changes in respiratory activity across different rodent species. They open up the powerful possibility of utilizing transgenic mouse technology for the advancement and translation of knowledge regarding sleep cycle alternations and their impact on respiration.
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Affiliation(s)
- Silvia Pagliardini
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada.
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26
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Darrah RJ, Bederman IR, Mitchell AL, Hodges CA, Campanaro CK, Drumm ML, Jacono FJ. Ventilatory pattern and energy expenditure are altered in cystic fibrosis mice. J Cyst Fibros 2013; 12:345-51. [PMID: 23290341 PMCID: PMC3620718 DOI: 10.1016/j.jcf.2012.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 11/15/2012] [Accepted: 11/16/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Altered ventilatory pattern and increased energy expenditure are facets of the complex cystic fibrosis (CF) phenotype. It is not known whether these are inherent attributes of CF, secondary consequences of lung infection or other disease complications. METHODS Studies were performed in congenic C57BL/6J, F508del (Cftr((tm1kth))) and CF gut-corrected (F508del) mice. Ventilatory patterns were measured using whole-body plethysmography. Indirect calorimetry was used to determine oxygen consumption, carbon dioxide production and resting energy expenditure. RESULTS CF mice (F508del and F508del gut-corrected) have a significantly faster respiratory rate and increased ventilatory pattern variability as compared to non-CF mice. F508del but not CF gut-corrected mice had significantly increased energy expenditure per gram body weight. CONCLUSIONS CF mice exhibit a faster, more variable ventilatory pattern. These changes were present in the absence of detectable infection or illness due to gastrointestinal obstruction. Increased resting energy expenditure does not completely account for these differences.
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Affiliation(s)
- Rebecca J Darrah
- Frances Payne Bolton School of Nursing, Case Western Reserve University, USA.
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27
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Davis EM, Locke LW, McDowell AL, Strollo PJ, O'Donnell CP. Obesity accentuates circadian variability in breathing during sleep in mice but does not predispose to apnea. J Appl Physiol (1985) 2013; 115:474-82. [PMID: 23722707 DOI: 10.1152/japplphysiol.00330.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Obesity is a primary risk factor for the development of obstructive sleep apnea in humans, but the impact of obesity on central sleep apnea is less clear. Given the comorbidities associated with obesity in humans, we developed techniques for long-term recording of diaphragmatic EMG activity and polysomnography in obese mice to assess breathing patterns during sleep and to determine the effect of obesity on apnea generation. We hypothesized that genetically obese ob/ob mice would exhibit less variability in breathing across the 24-h circadian cycle, be more prone to central apneas, and be more likely to exhibit patterns of increased diaphragm muscle activity consistent with obstructive apneas compared with lean mice. Unexpectedly, we found that obese mice exhibited a greater circadian impact on respiratory rate and diaphragmatic burst amplitude than lean mice, particularly during rapid eye movement (REM) sleep. Central apneas were more common in REM sleep (42 ± 17 h(-1)) than non-REM (NREM) sleep (14 ± 5 h(-1)) in obese mice (P < 0.05), but rates were not different between lean and obese mice in either sleep state. Even after experimentally enhancing central apnea generation by acute withdrawal of hypoxic chemoreceptor activation during sleep, central apnea rates remained comparable between lean and obese mice. Last, we were unable to detect patterns of diaphragmatic burst activity suggestive of obstructive apnea events in obese mice. In summary, obesity does not predispose mice to increased occurrence of central or obstructive apneas during sleep, but does lead to a more pronounced circadian variability in respiration.
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Affiliation(s)
- Eric M Davis
- Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh Medical Center, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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Davis EM, O'Donnell CP. Rodent models of sleep apnea. Respir Physiol Neurobiol 2013; 188:355-61. [PMID: 23722067 DOI: 10.1016/j.resp.2013.05.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 05/17/2013] [Accepted: 05/21/2013] [Indexed: 12/31/2022]
Abstract
Rodent models of sleep apnea have long been used to provide novel insight into the generation and predisposition to apneas as well as to characterize the impact of sleep apnea on cardiovascular, metabolic, and psychological health in humans. Given the significant body of work utilizing rodent models in the field of sleep apnea, the aims of this review are three-fold: first, to review the use of rodents as natural models of sleep apnea; second, to provide an overview of the experimental interventions employed in rodents to simulate sleep apnea; third, to discuss the refinement of rodent models to further our understanding of breathing abnormalities that occur during sleep. Given mounting evidence that sleep apnea impairs cognitive function, reduces quality of life, and exacerbates the course of multiple chronic diseases, rodent models will remain a high priority as a tool to interrogate both the pathophysiology and sequelae of breathing related abnormalities during sleep and to improve approaches to diagnosis and therapy.
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Affiliation(s)
- Eric M Davis
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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29
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Mayer CA, Ao J, Di Fiore JM, Martin RJ, MacFarlane PM. Impaired hypoxic ventilatory response following neonatal sustained and subsequent chronic intermittent hypoxia in rats. Respir Physiol Neurobiol 2013; 187:167-75. [PMID: 23562917 DOI: 10.1016/j.resp.2013.03.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/20/2013] [Accepted: 03/21/2013] [Indexed: 11/15/2022]
Abstract
Neonatal chronic intermittent hypoxia (CIH) enhances the ventilatory sensitivity to acute hypoxia (acute hypoxic ventilatory response, HVR), whereas sustained hypoxia (SH) can have the opposite effect. Therefore, we investigated whether neonatal rats pre-treated with SH prior to CIH exhibit a modified HVR. Rat pups were exposed to CIH (5% O2/5min, 8h/day) between 6 and 15 days of postnatal age (P6-15) after pre-treatment with either normoxia or SH (11% O2; P1-5). Using whole-body plethysmography, the acute (5min, 10% O2) HVR at P16 (1 day post-CIH) was unchanged following CIH (67.9±6.7% above baseline) and also SH (58.8±10.5%) compared to age-matched normoxic rats (54.7±6.3%). In contrast, the HVR was attenuated (16.5±6.0%) in CIH exposed rats pre-treated with SH. These data suggest that while neonatal SH and CIH alone have little effect on the magnitude of the acute HVR, their combined effects impose a synergistic disturbance to postnatal development of the HVR. These data could provide important insight into the consequences of not maintaining adequate levels of oxygen saturation during the early neonatal period, especially in vulnerable preterm infants susceptible to frequent bouts of hypoxemic events (CIH) that are commonly associated with apnea of prematurity.
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Affiliation(s)
- C A Mayer
- Department of Pediatrics, Case Western Reserve University, Rainbow Babies & Children's Hospital, Cleveland, OH 44106, USA
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30
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McShane BB, Galante RJ, Biber M, Jensen ST, Wyner AJ, Pack AI. Assessing REM sleep in mice using video data. Sleep 2012; 35:433-42. [PMID: 22379250 DOI: 10.5665/sleep.1712] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Assessment of sleep and its substages in mice currently requires implantation of chronic electrodes for measurement of electroencephalogram (EEG) and electromyogram (EMG). This is not ideal for high-throughput screening. To address this deficiency, we present a novel method based on digital video analysis. This methodology extends previous approaches that estimate sleep and wakefulness without EEG/EMG in order to now discriminate rapid eye movement (REM) from non-REM (NREM) sleep. DESIGN Studies were conducted in 8 male C57BL/6J mice. EEG/EMG were recorded for 24 hours and manually scored in 10-second epochs. Mouse behavior was continuously recorded by digital video at 10 frames/second. Six variables were extracted from the video for each 10-second epoch (i.e., intraepoch mean of velocity, aspect ratio, and area of the mouse and intraepoch standard deviation of the same variables) and used as inputs for our model. MEASUREMENTS AND RESULTS We focus on estimating features of REM (i.e., time spent in REM, number of bouts, and median bout length) as well as time spent in NREM and WAKE. We also consider the model's epoch-by-epoch scoring performance relative to several alternative approaches. Our model provides good estimates of these features across the day both when averaged across mice and in individual mice, but the epoch-by-epoch agreement is not as good. CONCLUSIONS There are subtle changes in the area and shape (i.e., aspect ratio) of the mouse as it transitions from NREM to REM, likely due to the atonia of REM, thus allowing our methodology to discriminate these two states. Although REM is relatively rare, our methodology can detect it and assess the amount of REM sleep.
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Affiliation(s)
- Blakeley B McShane
- Kellogg School of Management, Northwestern University, Evanston, IL, USA
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31
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Zeng T, Mott C, Mollicone D, Sanford LD. Automated determination of wakefulness and sleep in rats based on non-invasively acquired measures of movement and respiratory activity. J Neurosci Methods 2011; 204:276-87. [PMID: 22178621 DOI: 10.1016/j.jneumeth.2011.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 11/30/2011] [Accepted: 12/01/2011] [Indexed: 10/14/2022]
Abstract
The current standard for monitoring sleep in rats requires labor intensive surgical procedures and the implantation of chronic electrodes which have the potential to impact behavior and sleep. With the goal of developing a non-invasive method to determine sleep and wakefulness, we constructed a non-contact monitoring system to measure movement and respiratory activity using signals acquired with pulse Doppler radar and from digitized video analysis. A set of 23 frequency and time-domain features were derived from these signals and were calculated in 10s epochs. Based on these features, a classification method for automated scoring of wakefulness, non-rapid eye movement sleep (NREM) and REM in rats was developed using a support vector machine (SVM). We then assessed the utility of the automated scoring system in discriminating wakefulness and sleep by comparing the results to standard scoring of wakefulness and sleep based on concurrently recorded EEG and EMG. Agreement between SVM automated scoring based on selected features and visual scores based on EEG and EMG were approximately 91% for wakefulness, 84% for NREM and 70% for REM. The results indicate that automated scoring based on non-invasively acquired movement and respiratory activity will be useful for studies requiring discrimination of wakefulness and sleep. However, additional information or signals will be needed to improve discrimination of NREM and REM episodes within sleep.
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Affiliation(s)
- Tao Zeng
- Sleep Research Laboratory, Department of Anatomy and Pathology, Eastern Virginia Medical School, Norfolk, VA, USA
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32
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Hernandez AB, Kirkness JP, Smith PL, Schneider H, Polotsky M, Richardson RA, Hernandez WC, Schwartz AR. Novel whole body plethysmography system for the continuous characterization of sleep and breathing in a mouse. J Appl Physiol (1985) 2011; 112:671-80. [PMID: 22134700 DOI: 10.1152/japplphysiol.00818.2011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sleep is associated with marked alterations in ventilatory control that lead to perturbations in respiratory timing, breathing pattern, ventilation, pharyngeal collapsibility, and sleep-related breathing disorders (SRBD). Mouse models offer powerful insight into the pathogenesis of SRBD; however, methods for obtaining the full complement of continuous, high-fidelity respiratory, electroencephalographic (EEG), and electromyographic (EMG) signals in unrestrained mice during sleep and wake have not been developed. We adapted whole body plethysmography to record EEG, EMG, and respiratory signals continuously in unrestrained, unanesthetized mice. Whole body plethysmography tidal volume and airflow signals and a novel noninvasive surrogate for respiratory effort (respiratory movement signal) were validated against simultaneously measured gold standard signals. Compared with the gold standard, we validated 1) tidal volume (correlation, R(2) = 0.87, P < 0.001; and agreement within 1%, P < 0.001); 2) inspiratory airflow (correlation, R(2) = 0.92, P < 0.001; agreement within 4%, P < 0.001); 3) expiratory airflow (correlation, R(2) = 0.83, P < 0.001); and 4) respiratory movement signal (correlation, R(2) = 0.79-0.84, P < 0.001). The expiratory airflow signal, however, demonstrated a decrease in amplitude compared with the gold standard. Integrating respiratory and EEG/EMG signals, we fully characterized sleep and breathing patterns in conscious, unrestrained mice and demonstrated inspiratory flow limitation in a New Zealand Obese mouse. Our approach will facilitate studies of SRBD mechanisms in inbred mouse strains and offer a powerful platform to investigate the effects of environmental and pharmacological exposures on breathing disturbances during sleep and wakefulness.
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Affiliation(s)
- A B Hernandez
- Sleep Disorders Center, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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Rapid increase to double breathing rate appears during REM sleep in synchrony with REM - a higher CNS control of breathing? -. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010. [PMID: 20217359 DOI: 10.1007/978-1-4419-5692-7_50] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Breathing rate (BR) during rapid eye movement (REM) sleep is known to fluctuate largely, while increases in BR during REM sleep reported were small. In our mice experiments, we found that mice exhibit a rapid increase in instantaneous BR (RIBR) of >2 fold during natural sleep with accompanying atonia, laying their sides down. The RIBR was further found in a sleeping mouse attached with EEG electrodes when the EEG amplitude and delta wave power were lower. Therefore, it is likely that mice show RIBRs during REM sleep. Interestingly, similar RIBRs accompanied by atonia and REM burst during REM sleep were also found in humans by standard polysomnographic studies in 11 healthy volunteers (age: 22.3 +/- 2.8) with BR measurement by nasal/oral airflow sensors and chest/abdomen belt sensors. All subjects underwent RIBR of doubled BR at least once a night. As SpO(2) before RIBRs was a level not effective to be a respiratory stimulant (96.7 +/- 1.6 %, n = 63), the RIBR seems to be controlled by higher central nervous system rather than autonomic nervous system control on response to central and peripheral chemical sensors. In fact, tachypnea with suppressed amplitude during RIBR resulted in a slight fall in SpO(2) (96.4 +/- 1.7 %, p = 0.0007). In the present study, RIBRs accompanied by atonia and REM were not necessarily consistent in change in rate and/or amplitude, therefore, these various pattern of RIBRs may be potential indices of dreams with various emotional contents. Analysis of instantaneous BR, thus, may be a helpful tool for understanding the neural control of breathing during REM sleep.
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Assessment of a non-invasive high-throughput classifier for behaviours associated with sleep and wake in mice. Biomed Eng Online 2008; 7:14. [PMID: 18405376 PMCID: PMC2365952 DOI: 10.1186/1475-925x-7-14] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 04/11/2008] [Indexed: 11/10/2022] Open
Abstract
This work presents a non-invasive high-throughput system for automatically detecting characteristic behaviours in mice over extended periods of time, useful for phenotyping experiments. The system classifies time intervals on the order of 2 to 4 seconds as corresponding to motions consistent with either active wake or inactivity associated with sleep. A single Polyvinylidine Difluoride (PVDF) sensor on the cage floor generates signals from motion resulting in pressure. This paper develops a linear classifier based on robust features extracted from normalized power spectra and autocorrelation functions, as well as novel features from the collapsed average (autocorrelation of complex spectrum), which characterize transient and periodic properties of the signal envelope. Performance is analyzed through an experiment comparing results from direct human observation and classification of the different behaviours with an automatic classifier used in conjunction with this system. Experimental results from over 28.5 hours of data from 4 mice indicate a 94% classification rate relative to the human observations. Examples of sequential classifications (2 second increments) over transition regions between sleep and wake behaviour are also presented to demonstrate robust performance to signal variation and explain performance limitations.
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Stettner GM, Zanella S, Huppke P, Gärtner J, Hilaire G, Dutschmann M. Spontaneous central apneas occur in the C57BL/6J mouse strain. Respir Physiol Neurobiol 2007; 160:21-7. [PMID: 17869191 DOI: 10.1016/j.resp.2007.07.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 07/27/2007] [Accepted: 07/30/2007] [Indexed: 10/23/2022]
Abstract
Despite the clinical significance of central apneas in a wide range of disorders little is known about their pathogenesis. Research in this field has been hindered by the lack of appropriate animal models. Our goal was to determine whether the C57BL/6J mouse strain, which has an inherited predisposition for dysrhythmic breathing, exhibits spontaneous apneas. In vivo plethysmography of unanesthetized, unrestrained adult C57BL/6J mice revealed a regular occurrence of spontaneous apneas. In situ recordings from respiratory outputs (phrenic, vagal, hypoglossal nerves) in the working heart-brainstem preparation (WHBP) also showed spontaneous central apneas accompanied by laryngeal closure as indicated by tonic vagal postinspiratory activity and increase in subglottal pressure. The apneas were further characterized by a hypoglossal discharge with delayed onset compared to the tonic vagal postinspiratory activity. We conclude that spontaneous central apneas with active laryngeal closure occur in C57BL/6J mice. This mouse strain is a useful animal model to study neuronal mechanisms that underlie the generation of spontaneous central apneas.
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Affiliation(s)
- Georg M Stettner
- Department of Pediatrics and Pediatric Neurology, University Medicine Göttingen, Georg August University, Robert-Koch-Str. 40, D-37075 Göttingen, Germany.
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Mitzner W, Hantos Z, Irvin C, Tankersley C. Airway Responsiveness Should Be a Measurement of the Responsiveness of Airways. Am J Respir Crit Care Med 2007; 176:215; author reply 215-6. [PMID: 17617536 DOI: 10.1164/ajrccm.176.2.215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Douglas CL, Bowman GN, Baghdoyan HA, Lydic R. C57BL/6J and B6.V-LEPOB mice differ in the cholinergic modulation of sleep and breathing. J Appl Physiol (1985) 2004; 98:918-29. [PMID: 15475596 DOI: 10.1152/japplphysiol.00900.2004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Respiratory and arousal state control are heritable traits in mice. B6.V-Lep(ob) (ob) mice are leptin deficient and differ from C57BL/6J (B6) mice by a variation in the gene coding for leptin. The ob mouse has morbid obesity and disordered breathing that is homologous to breathing of obese humans. This study tested the hypothesis that microinjecting neostigmine into the pontine reticular nucleus, oral part (PnO), of B6 and ob mice alters sleep and breathing. In B6 and ob mice, neostigmine caused a concentration-dependent increase (P < 0.0001) in percentage of time spent in a rapid eye movement (REM) sleeplike state (REM-Neo). Relative to saline (control), higher concentrations of neostigmine increased REM-Neo duration and the number of REM-Neo episodes in B6 and ob mice and decreased percent wake, percent non-REM, and latency to onset of REM-Neo (P < 0.001). In B6 and ob mice, REM sleep enhancement by neostigmine was blocked by atropine. Differences in control amounts of sleep and wakefulness between B6 and the congenic ob mice also were identified. After PnO injection of saline, ob mice spent significantly (P < 0.05) more time awake and less time in non-REM sleep. B6 mice displayed more (P < 0.01) baseline locomotor activity than ob mice, and PnO neostigmine decreased locomotion (P < 0.0001) in B6 and ob mice. Whole body plethysmography showed that PnO neostigmine depressed breathing (P < 0.001) in B6 and ob mice and caused greater respiratory depression in B6 than ob mice (P < 0.05). Western blot analysis identified greater (P < 0.05) expression of M2 muscarinic receptor protein in ob than B6 mice for cortex, midbrain, cerebellum, and pons, but not medulla. Considered together, these data provide the first evidence that pontine cholinergic control of sleep and breathing varies between mice known to differ by a spontaneous mutation in the gene coding for leptin.
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Affiliation(s)
- Christopher L Douglas
- Department of Anesthesiology, University of Michigan, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-0615, USA
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