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Beitchman JA, Krishna G, Bromberg CE, Thomas TC. Effects of isoflurane and urethane anesthetics on glutamate neurotransmission in rat brain using in vivo amperometry. BMC Neurosci 2023; 24:52. [PMID: 37817064 PMCID: PMC10563344 DOI: 10.1186/s12868-023-00822-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 09/19/2023] [Indexed: 10/12/2023] Open
Abstract
BACKGROUND Aspects of glutamate neurotransmission implicated in normal and pathological conditions are predominantly evaluated using in vivo recording paradigms in rats anesthetized with isoflurane or urethane. Urethane and isoflurane anesthesia influence glutamate neurotransmission through different mechanisms; however, real-time outcome measures of potassium chloride (KCl)-evoked glutamate overflow and glutamate clearance kinetics have not been compared within and between regions of the brain. In order to maintain rigor and reproducibility within the literature between the two most common methods of anesthetized in vivo recording of glutamate, we compared glutamate signaling as a function of anesthesia and brain region in the rat strain most used in neuroscience. METHODS In the following experiments, in vivo amperometric recordings of KCl-evoked glutamate overflow and glutamate clearance kinetics (uptake rate and T80) in the cortex, hippocampus, and thalamus were performed using glutamate-selective microelectrode arrays (MEAs) in young adult male, Sprague-Dawley rats anesthetized with either isoflurane or urethane. RESULTS Potassium chloride (KCl)-evoked glutamate overflow was similar under urethane and isoflurane anesthesia in all brain regions studied. Analysis of glutamate clearance determined that the uptake rate was significantly faster (53.2%, p < 0.05) within the thalamus under urethane compared to isoflurane, but no differences were measured in the cortex or hippocampus. Under urethane, glutamate clearance parameters were region-dependent, with significantly faster glutamate clearance in the thalamus compared to the cortex but not the hippocampus (p < 0.05). No region-dependent differences were measured for glutamate overflow using isoflurane. CONCLUSIONS These data support that amperometric recordings of KCl-evoked glutamate under isoflurane and urethane anesthesia result in similar and comparable data. However, certain parameters of glutamate clearance can vary based on choice of anesthesia and brain region. In these circumstances, special considerations are needed when comparing previous literature and planning future experiments.
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Affiliation(s)
- Joshua A Beitchman
- Department of Child Health, University of Arizona College of Medicine - Phoenix, 425 N. 5th St. | 322 ABC-1 Building, Phoenix, AZ, 85004-2127, USA
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix Children's Hospital, Phoenix, AZ, USA
- College of Graduate Studies, Midwestern University, Glendale, AZ, USA
| | - Gokul Krishna
- Department of Child Health, University of Arizona College of Medicine - Phoenix, 425 N. 5th St. | 322 ABC-1 Building, Phoenix, AZ, 85004-2127, USA
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Caitlin E Bromberg
- Department of Child Health, University of Arizona College of Medicine - Phoenix, 425 N. 5th St. | 322 ABC-1 Building, Phoenix, AZ, 85004-2127, USA
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Theresa Currier Thomas
- Department of Child Health, University of Arizona College of Medicine - Phoenix, 425 N. 5th St. | 322 ABC-1 Building, Phoenix, AZ, 85004-2127, USA.
- Barrow Neurological Institute at Phoenix Children's Hospital, Phoenix Children's Hospital, Phoenix, AZ, USA.
- Phoenix VA Healthcare System, Phoenix, AZ, USA.
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Salavatian S, Kuwabara Y, Wong B, Fritz JR, Howard-Quijano K, Foreman RD, Armour JA, Ardell JL, Mahajan A. Spinal neuromodulation mitigates myocardial ischemia-induced sympathoexcitation by suppressing the intermediolateral nucleus hyperactivity and spinal neural synchrony. Front Neurosci 2023; 17:1180294. [PMID: 37332861 PMCID: PMC10272539 DOI: 10.3389/fnins.2023.1180294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction Myocardial ischemia disrupts the cardio-spinal neural network that controls the cardiac sympathetic preganglionic neurons, leading to sympathoexcitation and ventricular tachyarrhythmias (VTs). Spinal cord stimulation (SCS) is capable of suppressing the sympathoexcitation caused by myocardial ischemia. However, how SCS modulates the spinal neural network is not fully known. Methods In this pre-clinical study, we investigated the impact of SCS on the spinal neural network in mitigating myocardial ischemia-induced sympathoexcitation and arrhythmogenicity. Ten Yorkshire pigs with left circumflex coronary artery (LCX) occlusion-induced chronic myocardial infarction (MI) were anesthetized and underwent laminectomy and a sternotomy at 4-5 weeks post-MI. The activation recovery interval (ARI) and dispersion of repolarization (DOR) were analyzed to evaluate the extent of sympathoexcitation and arrhythmogenicity during the left anterior descending coronary artery (LAD) ischemia. Extracellular in vivo and in situ spinal dorsal horn (DH) and intermediolateral column (IML) neural recordings were performed using a multichannel microelectrode array inserted at the T2-T3 segment of the spinal cord. SCS was performed for 30 min at 1 kHz, 0.03 ms, 90% motor threshold. LAD ischemia was induced pre- and 1 min post-SCS to investigate how SCS modulates spinal neural network processing of myocardial ischemia. DH and IML neural interactions, including neuronal synchrony as well as cardiac sympathoexcitation and arrhythmogenicity markers were evaluated during myocardial ischemia pre- vs. post-SCS. Results ARI shortening in the ischemic region and global DOR augmentation due to LAD ischemia was mitigated by SCS. Neural firing response of ischemia-sensitive neurons during LAD ischemia and reperfusion was blunted by SCS. Further, SCS showed a similar effect in suppressing the firing response of IML and DH neurons during LAD ischemia. SCS exhibited a similar suppressive impact on the mechanical, nociceptive and multimodal ischemia sensitive neurons. The LAD ischemia and reperfusion-induced augmentation in neuronal synchrony between DH-DH and DH-IML pairs of neurons were mitigated by the SCS. Discussion These results suggest that SCS is decreasing the sympathoexcitation and arrhythmogenicity by suppressing the interactions between the spinal DH and IML neurons and activity of IML preganglionic sympathetic neurons.
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Affiliation(s)
- Siamak Salavatian
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
- Division of Cardiology, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Yuki Kuwabara
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Benjamin Wong
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Jonathan R. Fritz
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kimberly Howard-Quijano
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Robert D. Foreman
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - J. Andrew Armour
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Jeffrey L. Ardell
- Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Aman Mahajan
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
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Beitchman JA, Krishna G, Bromberg CE, Thomas TC. Effects of isoflurane and urethane anesthetics on glutamate neurotransmission in rat brain using in vivo amperometry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.16.528856. [PMID: 36824899 PMCID: PMC9949081 DOI: 10.1101/2023.02.16.528856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Aspects of glutamate neurotransmission implicated in normal and pathological conditions are often evaluated using in vivo recording paradigms in rats anesthetized with isoflurane or urethane. Urethane and isoflurane anesthesia influence glutamate neurotransmission through different mechanisms; however real-time outcome measures of potassium chloride (KCl)-evoked glutamate overflow and glutamate clearance kinetics have not been compared within and between regions of the brain. In the following experiments, in vivo amperometric recordings of KCl-evoked glutamate overflow and glutamate clearance kinetics (uptake rate and T80) in the cortex, hippocampus and thalamus were performed using glutamate-selective microelectrode arrays (MEAs) in young adult male, Sprague-Dawley rats anesthetized with isoflurane or urethane. Potassium chloride (KCl)-evoked glutamate overflow was similar under urethane and isoflurane anesthesia in all brain regions studied. Analysis of glutamate clearance determined that the uptake rate was significantly faster (53.2%, p<0.05) within the thalamus under urethane compared to isoflurane, but no differences were measured in the cortex or hippocampus. Under urethane, glutamate clearance parameters were region dependent, with significantly faster glutamate clearance in the thalamus compared to the cortex but not the hippocampus (p<0.05). No region dependent differences were measured for glutamate overflow using isoflurane. These data support that amperometric recordings of glutamate under isoflurane and urethane anesthesia result in mostly similar and comparable data. However, certain parameters of glutamate uptake vary based on choice of anesthesia and brain region. Special considerations must be given to these areas when considering comparison to previous literature and when planning future experiments.
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Affiliation(s)
- Joshua A. Beitchman
- BARROW Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ, USA
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
- College of Graduate Studies, Midwestern University, Glendale, AZ, USA
| | - Gokul Krishna
- BARROW Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ, USA
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Caitlin E. Bromberg
- BARROW Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ, USA
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
| | - Theresa Currier Thomas
- BARROW Neurological Institute at Phoenix Children’s Hospital, Phoenix, AZ, USA
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
- Phoenix VA Healthcare System, Phoenix, AZ, USA
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Luckl J, Baker W, Boda K, Emri M, Yodh AG, Greenberg JH. Oxyhemoglobin and Cerebral Blood Flow Transients Detect Infarction in Rat Focal Brain Ischemia. Neuroscience 2023; 509:132-144. [PMID: 36460221 PMCID: PMC9852213 DOI: 10.1016/j.neuroscience.2022.11.028] [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: 08/21/2022] [Revised: 11/18/2022] [Accepted: 11/23/2022] [Indexed: 11/30/2022]
Abstract
Spreading depolarizations (SD) refer to the near-complete depolarization of neurons that is associated with brain injuries such as ischemic stroke. The present gold standard for SD monitoring in humans is invasive electrocorticography (ECoG). A promising non-invasive alternative to ECoG is diffuse optical monitoring of SD-related flow and hemoglobin transients. To investigate the clinical utility of flow and hemoglobin transients, we analyzed their association with infarction in rat focal brain ischemia. Optical images of flow, oxy-hemoglobin, and deoxy-hemoglobin were continuously acquired with Laser Speckle and Optical Intrinsic Signal imaging for 2 h after photochemically induced distal middle cerebral artery occlusion in Sprague-Dawley rats (n = 10). Imaging was performed through a 6 × 6 mm window centered 3 mm posterior and 4 mm lateral to Bregma. Rats were sacrificed after 24 h, and the brain slices were stained for assessment of infarction. We mapped the infarcted area onto the imaging data and used nine circular regions of interest (ROI) to distinguish infarcted from non-infarcted tissue. Transients propagating through each ROI were characterized with six parameters (negative, positive, and total amplitude; negative and positive slope; duration). Transients were also classified into three morphology types (positive monophasic, biphasic, negative monophasic). Flow transient morphology, positive amplitude, positive slope, and total amplitude were all strongly associated with infarction (p < 0.001). Associations with infarction were also observed for oxy-hemoglobin morphology, oxy-hemoglobin positive amplitude and slope, and deoxy-hemoglobin positive slope and duration (all p < 0.01). These results suggest that flow and hemoglobin transients accompanying SD have value for detecting infarction.
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Affiliation(s)
- Janos Luckl
- Department of Neurology, University of Pennsylvania, Philadelphia, USA; Department of Neurology, University of Szeged, Szeged, Hungary; Department of Medical Physics and Informatics, Szeged, Hungary
| | - Wesley Baker
- Department of Neurology, Children's Hospital of Philadelphia, Philadelphia, USA; Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
| | - Krisztina Boda
- Department of Medical Physics and Informatics, Szeged, Hungary
| | - Miklos Emri
- Division of Nuclear Medicine and Translational Imaging, Department of Medical Imaging, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Arjun G Yodh
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, USA
| | - Joel H Greenberg
- Department of Neurology, University of Pennsylvania, Philadelphia, USA.
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5
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Hannan S, Faulkner M, Aristovich K, Avery J, Walker MC, Holder DS. Optimised induction of on-demand focal hippocampal and neocortical seizures by electrical stimulation. J Neurosci Methods 2020; 346:108911. [DOI: 10.1016/j.jneumeth.2020.108911] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 11/25/2022]
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6
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Xu JJ, Yousuf Z, Ouyang Z, Kennedy E, Lester PA, Martin T, Bruns TM. Anesthetic agents affect urodynamic parameters and anesthetic depth at doses necessary to facilitate preclinical testing in felines. Sci Rep 2020; 10:11401. [PMID: 32647241 PMCID: PMC7347647 DOI: 10.1038/s41598-020-68395-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 06/22/2020] [Indexed: 01/23/2023] Open
Abstract
Urodynamic studies, used to understand bladder function, diagnose bladder disease, and develop treatments for dysfunctions, are ideally performed with awake subjects. However, in small and medium-sized animal models, anesthesia is often required for these procedures and can be a research confounder. This study compared the effects of select survival agents (dexmedetomidine, alfaxalone, and propofol) on urodynamic (Δpressure, bladder capacity, bladder compliance, non-voiding contractions, bladder pressure slopes) and anesthetic (change in heart rate [∆HR], average heart rate [HR], reflexes, induction/recovery times) parameters in repeated cystometrograms across five adult male cats. The urodynamic parameters under isoflurane and α-chloralose were also examined in terminal procedures for four cats. Δpressure was greatest with propofol, bladder capacity was highest with α-chloralose, non-voiding contractions were greatest with α-chloralose. Propofol and dexmedetomidine had the highest bladder pressure slopes during the initial and final portions of the cystometrograms respectively. Cats progressed to a deeper plane of anesthesia (lower HR, smaller ΔHR, decreased reflexes) under dexmedetomidine, compared to propofol and alfaxalone. Time to induction was shortest with propofol, and time to recovery was shortest with dexmedetomidine. These agent-specific differences in urodynamic and anesthetic parameters in cats will facilitate appropriate study-specific anesthetic choices.
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Affiliation(s)
- Jiajie Jessica Xu
- Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI, USA.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA
| | - Zuha Yousuf
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, USA
| | - Zhonghua Ouyang
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, USA
| | - Eric Kennedy
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA.,Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, USA
| | - Patrick A Lester
- Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Tara Martin
- Unit for Laboratory Animal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Tim M Bruns
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, USA. .,Biomedical Engineering Department, University of Michigan, Ann Arbor, MI, USA.
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Chen W, Park K, Pan Y, Koretsky AP, Du C. Interactions between stimuli-evoked cortical activity and spontaneous low frequency oscillations measured with neuronal calcium. Neuroimage 2020; 210:116554. [PMID: 31972283 DOI: 10.1016/j.neuroimage.2020.116554] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/07/2019] [Accepted: 01/14/2020] [Indexed: 02/06/2023] Open
Abstract
Spontaneous brain activity has been widely used to map brain connectivity. The interactions between task-evoked brain responses and the spontaneous cortical oscillations, especially within the low frequency range of ~0.1 Hz, are not fully understood. Trial-to-trial variabilities in brain's response to sensory stimuli and the ability for brain to detect under noisy conditions suggest an appreciable impact of the brain state. Using a multimodality imaging platform, we simultaneously imaged neuronal Ca2+ and cerebral hemodynamics at baseline and in response to single-pulse forepaw stimuli in rat's somatosensory cortex. The high sensitivity of this system enables detection of responses to very weak and strong stimuli and real time determination of low frequency oscillations without averaging. Results show that the ongoing neuronal oscillations inversely modulate Ca2+ transients evoked by sensory stimuli. High intensity stimuli reset the spontaneous neuronal oscillations to an unpreferable excitability following the stimulus. Cerebral hemodynamic responses also inversely interact with the spontaneous hemodynamic oscillations, correlating with the neuronal Ca2+ transient changes. The results reveal competing interactions between spontaneous oscillations and stimulation-evoked brain activities in somatosensory cortex and the resultant hemodynamics.
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Affiliation(s)
- Wei Chen
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Kicheon Park
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Yingtian Pan
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA
| | - Alan P Koretsky
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Congwu Du
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY, 11794, USA.
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8
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Peri-infarct depolarizations during focal ischemia in the awake Spontaneously Hypertensive Rat. Minimizing anesthesia confounds in experimental stroke. Neuroscience 2016; 325:142-52. [PMID: 27026594 DOI: 10.1016/j.neuroscience.2016.03.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 02/02/2016] [Accepted: 03/21/2016] [Indexed: 11/22/2022]
Abstract
Anesthesia profoundly impacts peri-infarct depolarizations (PIDs), but only one prior report has described their monitoring during experimental stroke in awake animals. Since temporal patterns of PID occurrence are model specific, the current study examined PID incidence during focal ischemia in the awake Spontaneously Hypertensive Rat (SHR), and documented the impact of both prior and concurrent isoflurane anesthesia. For awake recordings, electrodes were implanted under isoflurane anesthesia 1day to 5weeks prior to occlusion surgery. Rats were then subjected to permanent or transient (2h) tandem occlusion of the middle cerebral and ipsilateral common carotid arteries, followed by PID monitoring for up to 3days. Comparison perfusion imaging studies evaluated PID-associated hyperemic transients during permanent ischemia under anesthesia at varied intervals following prior isoflurane exposure. Prior anesthesia attenuated PID number at intervals up to 1week, establishing 2weeks as a practical recovery duration following surgical preparation to avoid isoflurane preconditioning effects. PIDs in awake SHR were limited to the first 4h after permanent occlusions. Maintaining anesthesia during this interval reduced PID number, and prolonged their occurrence through several hours following anesthesia termination. Although PID number otherwise correlated with infarct size, PID suppression by anesthesia was not protective in the absence of reperfusion. PIDs persisted up to 36h after transient occlusions. These results differ markedly from the one previous report of such monitoring in awake Sprague-Dawley rats, which found an extended biphasic PID time course during 24h after both permanent and transient filament occlusions. PID occurrence closely reflects the time course of infarct progression in the respective models, and may be more useful than absolute PID number as an index of ongoing pathology.
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Bøttger P, Glerup S, Gesslein B, Illarionova NB, Isaksen TJ, Heuck A, Clausen BH, Füchtbauer EM, Gramsbergen JB, Gunnarson E, Aperia A, Lauritzen M, Lambertsen KL, Nissen P, Lykke-Hartmann K. Glutamate-system defects behind psychiatric manifestations in a familial hemiplegic migraine type 2 disease-mutation mouse model. Sci Rep 2016; 6:22047. [PMID: 26911348 PMCID: PMC4766516 DOI: 10.1038/srep22047] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 02/05/2016] [Indexed: 01/12/2023] Open
Abstract
Migraine is a complex brain disorder, and understanding the complexity of this prevalent disease could improve quality of life for millions of people. Familial Hemiplegic Migraine type 2 (FHM2) is a subtype of migraine with aura and co-morbidities like epilepsy/seizures, cognitive impairments and psychiatric manifestations, such as obsessive-compulsive disorder (OCD). FHM2 disease-mutations locate to the ATP1A2 gene encoding the astrocyte-located α2-isoform of the sodium-potassium pump (α2Na+/K+-ATPase). We show that knock-in mice heterozygous for the FHM2-associated G301R-mutation (α2+/G301R) phenocopy several FHM2-relevant disease traits e.g., by mimicking mood depression and OCD. In vitro studies showed impaired glutamate uptake in hippocampal mixed astrocyte-neuron cultures from α2G301R/G301R E17 embryonic mice, and moreover, induction of cortical spreading depression (CSD) resulted in reduced recovery in α2+/G301R male mice. Moreover, NMDA-type glutamate receptor antagonists or progestin-only treatment reverted specific α2+/G301R behavioral phenotypes. Our findings demonstrate that studies of an in vivo relevant FHM2 disease knock-in mouse model provide a link between the female sex hormone cycle and the glutamate system and a link to co-morbid psychiatric manifestations of FHM2.
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Affiliation(s)
- Pernille Bøttger
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,University of Southern Denmark, Institute of Molecular Medicine, Department of Neurobiology Research, DK-5000 Odense, Denmark
| | - Simon Glerup
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,The Lundbeck Foundation Research Centre MIND, Aarhus University, Department of Biomedicine, DK-8000 Aarhus C, Denmark
| | - Bodil Gesslein
- University of Copenhagen, Department of Neuroscience and Pharmacology and Center for Healthy Aging, DK-2200 Copenhagen N, Denmark
| | - Nina B Illarionova
- Karolinska Institutet, Department of Women's and Children's Health, SE-171 76 Stockholm, Sweden
| | - Toke J Isaksen
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark
| | - Anders Heuck
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark
| | - Bettina H Clausen
- University of Southern Denmark, Institute of Molecular Medicine, Department of Neurobiology Research, DK-5000 Odense, Denmark
| | | | - Jan B Gramsbergen
- University of Southern Denmark, Institute of Molecular Medicine, Department of Neurobiology Research, DK-5000 Odense, Denmark
| | - Eli Gunnarson
- Karolinska Institutet, Department of Women's and Children's Health, SE-171 76 Stockholm, Sweden
| | - Anita Aperia
- Karolinska Institutet, Department of Women's and Children's Health, SE-171 76 Stockholm, Sweden
| | - Martin Lauritzen
- University of Copenhagen, Department of Neuroscience and Pharmacology and Center for Healthy Aging, DK-2200 Copenhagen N, Denmark.,Glostrup Hospital, Department of Clinical Neurophysiology, DK-2600 Glostrup, Denmark
| | - Kate L Lambertsen
- University of Southern Denmark, Institute of Molecular Medicine, Department of Neurobiology Research, DK-5000 Odense, Denmark
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus, Denmark.,Danish Research Institute for Translational Neuroscience-DANDRITE, Nordic-EMBL Partnership of Molecular Medicine, Aarhus University, Department of Molecular Biology and Genetics and Department of Biomedicine, DK-8000 Aarhus C, Denmark
| | - Karin Lykke-Hartmann
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B DK-8000 Aarhus C, Denmark
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10
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Yang CC, Li L, Zheng SS, Lu J, Zhang L, Li YL, Zhang L. Cornel iridoid glycoside reduces infarct size measured by magnetic resonance imaging and improves neurological function after focal cerebral ischemia in rats. Chin J Integr Med 2015. [PMID: 26264574 DOI: 10.1007/s11655-015-2288-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To investigate the effect of cornel iridoid glycoside (CIG), an ingredient extracted from traditional Chinese herb Cornus offificinalis, on neurological function and infarct size in rats as measured by magnetic resonance imaging (MRI) after ischemic stroke. METHODS Sprague-Dawley rats were divided into three group: control (n=11), model (n=20) and CIG (n=16) groups. Rats in the model and CIG groups underwent 90-min middle cerebral artery occlusion (MCAO) followed by reperfusion. Their neurological defect was measured by using a modified neurological severity score (mNSS). T2-weighted MRI (T2-MRI) of the brain was performed in vivo from 2 to 28 days after MCAO. The infarct volume in the brain was also measured using 2,3,5-triphenyltetrazolium chloride (TTC) staining 28 days after stroke. RESULTS CIG, 60 mg/(kg day), administered by oral gavage starting from 6 h after the onset of MCAO improved neurological function at 7, 14, 21, and 28 days post occlusion (P<0.05 orP<0.01) and decreased mortality. The infarct volumes computed from the T2-MR images were reduced in the CIG-treated group compared with the model group at 7, 14 and 28 days after MCAO (P<0.05); and the rate at which the infarct volume decreased from 2 to 28 days was higher in the CIG-treated group than that in the model group (P<0.05). The infarct volumes measured by TTC staining were also decreased 28 days after stroke (P<0.05). CONCLUSION CIG treatment, starting from 6 h after MCAO, reduced infarct size in the brain as measured by MRI and improved neurological function 2-28 days after focal cerebral ischemia in rats, suggesting that CIG could be a clinical application in improving stroke treatment.
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Affiliation(s)
- Cui-Cui Yang
- Department of Pharmacology, Xuanwu Hospital of Capital Medical University, Beijing Institute for Brain Disorders, Key Laboratory for Neurodegenerative Diseases of Ministry of Education, Beijing, 100053, China
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11
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Preconditioning cortical lesions reduce the incidence of peri-infarct depolarizations during focal ischemia in the Spontaneously Hypertensive Rat: interaction with prior anesthesia and the impact of hyperglycemia. J Cereb Blood Flow Metab 2015; 35:1181-90. [PMID: 25757750 PMCID: PMC4640273 DOI: 10.1038/jcbfm.2015.37] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/16/2015] [Accepted: 02/08/2015] [Indexed: 02/07/2023]
Abstract
The relationship between peri-infarct depolarizations (PIDs) and infarction was investigated in a model of preconditioning by cortical freeze lesions (cryogenic lesions, CL) in the Spontaneously Hypertensive Rat. Small (< 5 mm(3)) lesions produced 24 hours before permanent focal ischemia were protective, without impacting baseline cerebral blood flow (CBF) and metabolism. Prior CL reduced infarct volume, associated with improved penumbral CBF as previously showed for ischemic preconditioning. The brief initial procedure avoided sham effects on infarct volume after subsequent occlusion under brief anesthesia. However, under prolonged isoflurane anesthesia for perfusion monitoring both sham and CL rats showed reduced PID incidence relative to naive animals. This anesthesia effect could be eliminated by using α-chloralose during perfusion imaging. As an additional methodological concern, blood glucose was frequently elevated at the time of the second surgery, reflecting buprenorphine-induced pica and other undefined mechanisms. Even modest hyperglycemia (>10 mmol/L) reduced PID incidence. In normoglycemic animals CL preconditioning reduced PID number by 50%, demonstrating associated effects on PID incidence, penumbral perfusion, and infarct progression. Hyperglycemia suppressed PIDs without affecting the relationship between CBF and infarction. This suggests that the primary effect of preconditioning is to improve penumbral perfusion, which in turn impacts PID incidence and infarct size.
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Lu XCM, Mountney A, Chen Z, Wei G, Cao Y, Leung LY, Khatri V, Cunningham T, Tortella FC. Similarities and differences of acute nonconvulsive seizures and other epileptic activities following penetrating and ischemic brain injuries in rats. J Neurotrauma 2013; 30:580-90. [PMID: 23234254 DOI: 10.1089/neu.2012.2641] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The similarities and differences between acute nonconvulsive seizures (NCS) and other epileptic events, for example, periodic epileptiform discharges (PED) and intermittent rhythmic delta activities (IRDA), were characterized in rat models of penetrating and ischemic brain injuries. The NCS were spontaneously induced by either unilateral frontal penetrating ballistic-like brain injury (PBBI) or permanent middle cerebral artery occlusion (pMCAO), and were detected by continuous electroencephalogram (EEG) monitoring begun immediately after the injury and continued for 72 h or 24 h, respectively. Analysis of NCS profiles (incidence, frequency, duration, and time distribution) revealed a high NCS incidence in both injury models. The EEG waveform expressions of NCS and PED exhibited intrinsic variations that resembled human electrographic manifestations of post-traumatic and post-ischemic ictal and inter-ictal events, but these waveform variations were not distinguishable between the two types of brain injury. However, the NCS after pMCAO occurred more acutely and intensely (latency=0.6 h, frequency=25 episodes/rat) compared with the PBBI-induced NCS (latency=24 h, frequency=10 episodes/rat), such that the most salient features differentiating post-traumatic and post-ischemic NCS were the intensity and time distribution of the NCS profiles. After pMCAO, nearly 50% of the seizures occurred within the first 2 h of injury, whereas after PBBI, NCS occurred sporadically (0-5%/h) throughout the 72 h recording period. The PED were episodically associated with NCS. By contrast, the IRDA appeared to be independent of other epileptic events. This study provided comprehensive comparisons of post-traumatic and post-ischemic epileptic profiles. The identification of the similarities and differences across a broad spectrum of epileptic events may lead to differential strategies for post-traumatic and post-stroke seizure interventions.
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Affiliation(s)
- Xi-Chun May Lu
- Branch of Brain Trauma Neuroprotection and Neurorestoration, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA
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Lückl J, Dreier JP, Szabados T, Wiesenthal D, Bari F, Greenberg JH. Peri-infarct flow transients predict outcome in rat focal brain ischemia. Neuroscience 2012; 226:197-207. [PMID: 22986160 DOI: 10.1016/j.neuroscience.2012.08.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/10/2012] [Accepted: 08/23/2012] [Indexed: 01/09/2023]
Abstract
Spreading depolarizations are accompanied by transient changes in cerebral blood flow (CBF). In a post hoc analysis of previously studied control rats we analyzed CBF time courses after middle cerebral artery occlusion in the rat in order to test whether intra-ischemic flow, reperfusion, and different parameters of peri-infarct flow transients (PIFTs) (amplitude, number) can predict outcome. Sprague-Dawley rats anesthetized with either halothane (n=23) or isoflurane (n=32) underwent 90-min filament occlusion of the middle cerebral artery followed by 72 h of reperfusion. The infarct size was determined by 2,3,5-triphenyltetrazolium chloride staining. Relative CBF changes were monitored by laser Doppler flowmetry at 4-5 mm lateral, and 1-2mm posterior to Bregma. An additional filament occlusion study (n=12) was performed to validate that PIFTs were coupled to direct current shifts of spreading depolarization. The PIFT-direct current shift study revealed that every PIFT was associated with a negative direct current shift typical of spreading depolarization. Post-hoc analysis showed that the number of PIFTs, especially with the combination of intra-ischemic level of flow, can predict the development of cortical infarcts. These findings show that PIFTs can serve as an early biomarker in predicting outcome in preclinical animal studies.
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Affiliation(s)
- J Lückl
- Department of Neurology, University of Pennsylvania, 415 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA 19104-6063, USA
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Hiraki T, Baker W, Greenberg JH. Effect of vagus nerve stimulation during transient focal cerebral ischemia on chronic outcome in rats. J Neurosci Res 2012; 90:887-94. [PMID: 22420043 DOI: 10.1002/jnr.22812] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The aim of this study was to investigate the effect of vagus nerve stimulation (VNS) on infarct volume and neurological recovery up to 3 weeks following transient focal cerebral ischemia. Transient ischemia was produced by filament occlusion of the proximal middle cerebral artery (MCA) in rats. The right vagus nerve was stimulated starting 30 min after MCA occlusion and consisted of 30-sec pulse trains (20 Hz) delivered to the animal's right vagus nerve every 5 min for a total period of 60 min (n = 10). All the procedures were duplicated, but no stimulus was delivered, in a control group (n = 10). Neurological evaluations were performed in all animals at 24 hr, 48 hr, 1 week, 2 weeks, and 3 weeks after MCA occlusion; animals were euthanized; and neuronal damage was evaluated in hematoxylin-eosin-stained sections. The ischemic lesion volume was smaller in the VNS-treated animals in comparison with the nonstimulated group (P < 0.02). Although the functional score in both treated and untreated groups improved over the 3-week observation period (P < 0.001), there was still a statistically significant improvement reszulting from VNS treatment compared with control animals (P < 0.05). Cerebral blood flow changes in the MCA territory during ischemia did not differ between the VNS-treated animals (31.9% ± 10.4% of baseline) and control animals (29.9% ± 9.1%; P = 0.6). Stimulation of the vagus nerve for only a brief period early in ischemia provides neuroprotection in transient ischemia, with neuroprotection persisting for at least 3 weeks.
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Affiliation(s)
- Teruyuki Hiraki
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104-6063, USA
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Metabolic and perfusion responses to recurrent peri-infarct depolarization during focal ischemia in the Spontaneously Hypertensive Rat: dominant contribution of sporadic CBF decrements to infarct expansion. J Cereb Blood Flow Metab 2011; 31:1863-73. [PMID: 21522165 PMCID: PMC3185883 DOI: 10.1038/jcbfm.2011.62] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Peri-infarct depolarizations (PIDs) contribute to the evolution of focal ischemic lesions. Proposed mechanisms include both increased metabolic demand under conditions of attenuated perfusion and overt vasoconstrictive responses to depolarization. The present studies investigated the relative contributions of metabolic and perfusion effects to PID-associated infarct expansion during middle cerebral artery (MCA) occlusion in the Spontaneously Hypertensive Rat. The initial distribution of ischemic depolarization (ID) was established within minutes after MCA occlusion at a cerebral blood flow threshold of ∼40 mL/100 g per minute, with expansion of the depolarized territory during 3 hours detected in half of the animals. Peri-infarct depolarizations were associated with transient metabolic responses, comparable to those observed after spreading depression, with no evidence of cumulative energy failure after multiple transient depolarizations during 1 hour. Speckle contrast imaging of PID-associated flow transients documented prominent distal hyperemic flow responses that became progressively attenuated in regions of already impaired perfusion, with modest propagated flow decreases more proximal to the ischemic core. However, sporadic PIDs were associated with persistent decrements in perfusion, increasing tissue volume below the threshold for energy failure, ID and infarction. These latter, comparatively rare, events can account for the pattern of stepwise infarct expansion in this model.
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Sun Z, Baker W, Hiraki T, Greenberg JH. The effect of right vagus nerve stimulation on focal cerebral ischemia: an experimental study in the rat. Brain Stimul 2011; 5:1-10. [PMID: 22037134 DOI: 10.1016/j.brs.2011.01.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 12/21/2010] [Accepted: 01/24/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The aim of this study was to determine the effect of vagus nerve stimulation (VNS) on infarct size after transient and after permanent focal cerebral ischemia in rats and to test the hypothesis that VNS-induced neuroprotection is due to changes in cerebral blood flow. METHODS Ischemia was produced by either temporary proximal middle cerebral artery occlusion (TMCAO) or permanent distal middle cerebral artery occlusion (PMCAO). Stimulating electrodes were implanted on the cervical part of the right vagus nerve, and electrical stimulation was initiated 30 minutes after the induction of ischemia and delivered for 30 seconds every 5 minutes for 1 hour. All the procedures were duplicated but no stimulus was delivered in control groups. Cerebral blood flow in the MCA territory was continuously monitored with laser speckle contrast imaging. A neurologic evaluation was undertaken after 24 hours of ischemia, and animals were euthanized and neuronal damage evaluated. RESULTS Ischemic lesion volume was smaller in VNS-treated animals in both the temporary and permanent ischemic groups (P<.01). VNS-treated animals in TMCAO had better functional scores at 24 hours as compared with control animals (P<.01), but there were no statistically significant differences in the neurobehavioral scores in PMCAO (P=.089). Cerebral blood flow changes in the MCA territory during ischemia did not differ between the VNS-treated animals and control animals in either group. CONCLUSIONS VNS offers neuroprotection against stroke in both temporary and permanent ischemia. Although the precise mechanism of this effect remains to be determined, alterations in cerebral blood flow do not appear to play a role. VNS could readily be translated to clinical practice.
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Affiliation(s)
- Zhenghui Sun
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6063, USA
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de Celis Alonso B, Makarova T, Hess A. On the use of α-chloralose for repeated BOLD fMRI measurements in rats. J Neurosci Methods 2011; 195:236-40. [DOI: 10.1016/j.jneumeth.2010.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 11/30/2010] [Accepted: 12/02/2010] [Indexed: 11/26/2022]
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Luckl J, Baker W, Sun ZH, Durduran T, Yodh AG, Greenberg JH. The biological effect of contralateral forepaw stimulation in rat focal cerebral ischemia: a multispectral optical imaging study. FRONTIERS IN NEUROENERGETICS 2010; 2. [PMID: 20725601 PMCID: PMC2922941 DOI: 10.3389/fnene.2010.00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 07/05/2010] [Indexed: 11/22/2022]
Abstract
Our group has already published the possible neuroprotective effect of contralateral forepaw stimulation in temporary focal ischemia in a study. However, the background is still unclear. In the present study we investigated the possible mechanism by monitoring focal ischemia with multispectral [laser speckle, imaging of intrinsic signals (OIS)] imaging. Sprague–Dawley rats were prepared using 1.2% isoflurane anesthesia. The middle cerebral artery was occluded by photothrombosis (4 mW) and the common carotid artery was ligated permanently. Physiological variables were constantly monitored during the experiment. A 6 × 6 mm area centered 3 mm posterior and 4 mm lateral to Bregma was thinned for laser speckle and OIS imaging. Nine circular regions of interests (0.3 mm in diameter) were evenly spaced on the speckle contrast image for the analysis of peri-infarct flow transients, blood flow, and metabolic changes. Both the sham (n = 7) and forepaw-stimulated animals (n = 7) underwent neurological examinations 24 h after ischemia at which point all animals were sacrificed and the infarct size was determined by triphenyltetrazolium chloride. The physiological variables were in normal range and the experimental protocol did not cause significant differences between groups. Both the neurological scores (sham: 3.6 ± 1.7, stimulated: 4.3 ± 1.4) and the infarct volume (sham: 124 ± 39 mm3, stimulated: 147 ± 47 mm3) did not show significant differences between groups. The forepaw stimulation did not increase the intra-ischemic flow neither over the penumbral or the peri-ischemic area. However, the hemoglobin transients related metabolic load (CMRO2) was significantly lower (p < 0.001) while the averaged number of hyperemic flow transients were significantly (p = 0.013) higher in the forepaw (sham: 3.5 ± 2.2, stimulated: 7.0 ± 2.3) stimulated animals.
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Affiliation(s)
- Janos Luckl
- Department of Neurology, University of Pennsylvania Philadelphia, PA, USA
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Williams KA, Magnuson M, Majeed W, LaConte SM, Peltier SJ, Hu X, Keilholz SD. Comparison of alpha-chloralose, medetomidine and isoflurane anesthesia for functional connectivity mapping in the rat. Magn Reson Imaging 2010; 28:995-1003. [PMID: 20456892 DOI: 10.1016/j.mri.2010.03.007] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 01/18/2010] [Accepted: 03/11/2010] [Indexed: 12/19/2022]
Abstract
Functional connectivity measures based upon low-frequency blood-oxygenation-level-dependent functional magnetic resonance imaging (BOLD fMRI) signal fluctuations have become a widely used tool for investigating spontaneous brain activity in humans. Still unknown, however, is the precise relationship between neural activity, the hemodynamic response and fluctuations in the MRI signal. Recent work from several groups had shown that correlated low-frequency fluctuations in the BOLD signal can be detected in the anesthetized rat - a first step toward elucidating this relationship. Building on this preliminary work, through this study, we demonstrate that functional connectivity observed in the rat depends strongly on the type of anesthesia used. Power spectra of spontaneous fluctuations and the cross-correlation-based connectivity maps from rats anesthetized with alpha-chloralose, medetomidine or isoflurane are presented using a high-temporal-resolution imaging sequence that ensures minimal contamination from physiological noise. The results show less localized correlation in rats anesthetized with isoflurane as compared with rats anesthetized with alpha-chloralose or medetomidine. These experiments highlight the utility of using different types of anesthesia to explore the fundamental physiological relationships of the BOLD signal and suggest that the mechanisms contributing to functional connectivity involve a complicated relationship between changes in neural activity, neurovascular coupling and vascular reactivity.
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Affiliation(s)
- Kathleen A Williams
- Department of Radiology, Center for Biomedical Imaging, New York University School of Medicine, New York, NY 10012, USA
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Luckl J, Zhou C, Durduran T, Yodh AG, Greenberg JH. Characterization of periinfarct flow transients with laser speckle and Doppler after middle cerebral artery occlusion in the rat. J Neurosci Res 2009; 87:1219-29. [DOI: 10.1002/jnr.21933] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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