1
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Kann O. Lactate as a supplemental fuel for synaptic transmission and neuronal network oscillations: Potentials and limitations. J Neurochem 2024; 168:608-631. [PMID: 37309602 DOI: 10.1111/jnc.15867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 06/14/2023]
Abstract
Lactate shuttled from the blood circulation, astrocytes, oligodendrocytes or even activated microglia (resident macrophages) to neurons has been hypothesized to represent a major source of pyruvate compared to what is normally produced endogenously by neuronal glucose metabolism. However, the role of lactate oxidation in fueling neuronal signaling associated with complex cortex function, such as perception, motor activity, and memory formation, is widely unclear. This issue has been experimentally addressed using electrophysiology in hippocampal slice preparations (ex vivo) that permit the induction of different neural network activation states by electrical stimulation, optogenetic tools or receptor ligand application. Collectively, these studies suggest that lactate in the absence of glucose (lactate only) impairs gamma (30-70 Hz) and theta-gamma oscillations, which feature high energy demand revealed by the cerebral metabolic rate of oxygen (CMRO2, set to 100%). The impairment comprises oscillation attenuation or moderate neural bursts (excitation-inhibition imbalance). The bursting is suppressed by elevating the glucose fraction in energy substrate supply. By contrast, lactate can retain certain electric stimulus-induced neural population responses and intermittent sharp wave-ripple activity that features lower energy expenditure (CMRO2 of about 65%). Lactate utilization increases the oxygen consumption by about 9% during sharp wave-ripples reflecting enhanced adenosine-5'-triphosphate (ATP) synthesis by oxidative phosphorylation in mitochondria. Moreover, lactate attenuates neurotransmission in glutamatergic pyramidal cells and fast-spiking, γ-aminobutyric acid (GABA)ergic interneurons by reducing neurotransmitter release from presynaptic terminals. By contrast, the generation and propagation of action potentials in the axon is regular. In conclusion, lactate is less effective than glucose and potentially detrimental during neural network rhythms featuring high energetic costs, likely through the lack of some obligatory ATP synthesis by aerobic glycolysis at excitatory and inhibitory synapses. High lactate/glucose ratios might contribute to central fatigue, cognitive impairment, and epileptic seizures partially seen, for instance, during exhaustive physical exercise, hypoglycemia and neuroinflammation.
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Affiliation(s)
- Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
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2
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Ponomareva D, Ivanov A, Bregestovski P. Analysis of the Effects of Pentose Phosphate Pathway Inhibition on the Generation of Reactive Oxygen Species and Epileptiform Activity in Hippocampal Slices. Int J Mol Sci 2024; 25:1934. [PMID: 38339211 PMCID: PMC10856462 DOI: 10.3390/ijms25031934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 01/27/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024] Open
Abstract
The pentose phosphate pathway (PPP) is one of three major pathways involved in glucose metabolism, which is regulated by glucose-6-phosphate dehydrogenase (G6PD) controls NADPH formation. NADPH, in turn, regulates the balance of oxidative stress and reactive oxygen species (ROS) levels. G6PD dysfunction, affecting the PPP, is implicated in neurological disorders, including epilepsy. However, PPP's role in epileptogenesis and ROS production during epileptic activity remains unclear. To clarify these points, we conducted electrophysiological and imaging analyses on mouse hippocampal brain slices. Using the specific G6PD inhibitor G6PDi-1, we assessed its effects on mouse hippocampal slices, examining intracellular ROS, glucose/oxygen consumption, the NAD(P)H level and ROS production during synaptic stimulation and in the 4AP epilepsy model. G6PDi-1 increased basal intracellular ROS levels and reduced synaptically induced glucose consumption but had no impact on baselevel of NAD(P)H and ROS production from synaptic stimulation. In the 4AP model, G6PDi-1 did not significantly alter spontaneous seizure frequency or H2O2 release amplitude but increased the frequency and peak amplitude of interictal events. These findings suggest that short-term PPP inhibition has a minimal impact on synaptic circuit activity.
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Affiliation(s)
- Daria Ponomareva
- Department of Physiology, Kazan State Medical University, 420012 Kazan, Russia;
- Institute of Neuroscience, Kazan State Medical University, 420012 Kazan, Russia
- INSERM, Institut de Neurosciences des Systèmes (INS), UMR1106, Aix-Marseille Université, 13005 Marseille, France;
| | - Anton Ivanov
- INSERM, Institut de Neurosciences des Systèmes (INS), UMR1106, Aix-Marseille Université, 13005 Marseille, France;
| | - Piotr Bregestovski
- Department of Physiology, Kazan State Medical University, 420012 Kazan, Russia;
- Institute of Neuroscience, Kazan State Medical University, 420012 Kazan, Russia
- INSERM, Institut de Neurosciences des Systèmes (INS), UMR1106, Aix-Marseille Université, 13005 Marseille, France;
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3
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Aging and memory are altered by genetically manipulating lactate dehydrogenase in the neurons or glia of flies. Aging (Albany NY) 2023; 15:947-981. [PMID: 36849157 PMCID: PMC10008500 DOI: 10.18632/aging.204565] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/20/2023] [Indexed: 03/01/2023]
Abstract
The astrocyte-neuron lactate shuttle hypothesis posits that glial-generated lactate is transported to neurons to fuel metabolic processes required for long-term memory. Although studies in vertebrates have revealed that lactate shuttling is important for cognitive function, it is uncertain if this form of metabolic coupling is conserved in invertebrates or is influenced by age. Lactate dehydrogenase (Ldh) is a rate limiting enzyme that interconverts lactate and pyruvate. Here we genetically manipulated expression of Drosophila melanogaster lactate dehydrogenase (dLdh) in neurons or glia to assess the impact of altered lactate metabolism on invertebrate aging and long-term courtship memory at different ages. We also assessed survival, negative geotaxis, brain neutral lipids (the core component of lipid droplets) and brain metabolites. Both upregulation and downregulation of dLdh in neurons resulted in decreased survival and memory impairment with age. Glial downregulation of dLdh expression caused age-related memory impairment without altering survival, while upregulated glial dLdh expression lowered survival without disrupting memory. Both neuronal and glial dLdh upregulation increased neutral lipid accumulation. We provide evidence that altered lactate metabolism with age affects the tricarboxylic acid (TCA) cycle, 2-hydroxyglutarate (2HG), and neutral lipid accumulation. Collectively, our findings indicate that the direct alteration of lactate metabolism in either glia or neurons affects memory and survival but only in an age-dependent manner.
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Turner KL, Gheres KW, Drew PJ. Relating Pupil Diameter and Blinking to Cortical Activity and Hemodynamics across Arousal States. J Neurosci 2023; 43:949-964. [PMID: 36517240 PMCID: PMC9908322 DOI: 10.1523/jneurosci.1244-22.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Arousal state affects neural activity and vascular dynamics in the cortex, with sleep associated with large changes in the local field potential and increases in cortical blood flow. We investigated the relationship between pupil diameter and blink rate with neural activity and blood volume in the somatosensory cortex in male and female unanesthetized, head-fixed mice. We monitored these variables while the mice were awake, during periods of rapid eye movement (REM), and non-rapid eye movement (NREM) sleep. Pupil diameter was smaller during sleep than in the awake state. Changes in pupil diameter were coherent with both gamma-band power and blood volume in the somatosensory cortex, but the strength and sign of this relationship varied with arousal state. We observed a strong negative correlation between pupil diameter and both gamma-band power and blood volume during periods of awake rest and NREM sleep, although the correlations between pupil diameter and these signals became positive during periods of alertness, active whisking, and REM. Blinking was associated with increases in arousal and decreases in blood volume when the mouse was asleep. Bilateral coherence in gamma-band power and in blood volume dropped following awake blinking, indicating a reset of neural and vascular activity. Using only eye metrics (pupil diameter and eye motion), we could determine the arousal state of the mouse ('Awake,' 'NREM,' 'REM') with >90% accuracy with a 5 s resolution. There is a strong relationship between pupil diameter and hemodynamics signals in mice, reflecting the pronounced effects of arousal on cerebrovascular dynamics.SIGNIFICANCE STATEMENT Determining arousal state is a critical component of any neuroscience experiment. Pupil diameter and blinking are influenced by arousal state, as are hemodynamics signals in the cortex. We investigated the relationship between cortical hemodynamics and pupil diameter and found that pupil diameter was strongly related to the blood volume in the cortex. Mice were more likely to be awake after blinking than before, and blinking resets neural activity. Pupil diameter and eye motion can be used as a reliable, noninvasive indicator of arousal state. As mice transition from wake to sleep and back again over a timescale of seconds, monitoring pupil diameter and eye motion permits the noninvasive detection of sleep events during behavioral or resting-state experiments.
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Affiliation(s)
- Kevin L Turner
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Kyle W Gheres
- Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Departments of Engineering Science and Mechanics
| | - Patrick J Drew
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Departments of Engineering Science and Mechanics
- Biology and Neurosurgery, Pennsylvania State University, University Park, Pennsylvania 16802
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5
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Ponomareva D, Petukhova E, Bregestovski P. Simultaneous Monitoring of pH and Chloride (Cl -) in Brain Slices of Transgenic Mice. Int J Mol Sci 2021; 22:13601. [PMID: 34948398 PMCID: PMC8708776 DOI: 10.3390/ijms222413601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022] Open
Abstract
Optosensorics is the direction of research possessing the possibility of non-invasive monitoring of the concentration of intracellular ions or activity of intracellular components using specific biosensors. In recent years, genetically encoded proteins have been used as effective optosensory means. These probes possess fluorophore groups capable of changing fluorescence when interacting with certain ions or molecules. For monitoring of intracellular concentrations of chloride ([Cl-]i) and hydrogen ([H+] i) the construct, called ClopHensor, which consists of a H+- and Cl--sensitive variant of the enhanced green fluorescent protein (E2GFP) fused with a monomeric red fluorescent protein (mDsRed) has been proposed. We recently developed a line of transgenic mice expressing ClopHensor in neurons and obtained the map of its expression in different areas of the brain. The purpose of this study was to examine the effectiveness of transgenic mice expressing ClopHensor for estimation of [H+]i and [Cl-]i concentrations in neurons of brain slices. We performed simultaneous monitoring of [H+]i and [Cl-]i under different experimental conditions including changing of external concentrations of ions (Ca2+, Cl-, K+, Na+) and synaptic stimulation of Shaffer's collaterals of hippocampal slices. The results obtained illuminate different pathways of regulation of Cl- and pH equilibrium in neurons and demonstrate that transgenic mice expressing ClopHensor represent a reliable tool for non-invasive simultaneous monitoring of intracellular Cl- and pH.
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Affiliation(s)
- Daria Ponomareva
- Institut de Neurosciences des Systèmes, Aix-Marseille University, INSERM, INS, 13005 Marseille, France;
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia;
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
| | - Elena Petukhova
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia;
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
| | - Piotr Bregestovski
- Institut de Neurosciences des Systèmes, Aix-Marseille University, INSERM, INS, 13005 Marseille, France;
- Institute of Neurosciences, Kazan State Medical University, 420111 Kazan, Russia;
- Department of Normal Physiology, Kazan State Medical University, 420111 Kazan, Russia
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6
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Karagiannis A, Gallopin T, Lacroix A, Plaisier F, Piquet J, Geoffroy H, Hepp R, Naudé J, Le Gac B, Egger R, Lambolez B, Li D, Rossier J, Staiger JF, Imamura H, Seino S, Roeper J, Cauli B. Lactate is an energy substrate for rodent cortical neurons and enhances their firing activity. eLife 2021; 10:e71424. [PMID: 34766906 PMCID: PMC8651295 DOI: 10.7554/elife.71424] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 11/09/2021] [Indexed: 12/12/2022] Open
Abstract
Glucose is the mandatory fuel for the brain, yet the relative contribution of glucose and lactate for neuronal energy metabolism is unclear. We found that increased lactate, but not glucose concentration, enhances the spiking activity of neurons of the cerebral cortex. Enhanced spiking was dependent on ATP-sensitive potassium (KATP) channels formed with KCNJ11 and ABCC8 subunits, which we show are functionally expressed in most neocortical neuronal types. We also demonstrate the ability of cortical neurons to take-up and metabolize lactate. We further reveal that ATP is produced by cortical neurons largely via oxidative phosphorylation and only modestly by glycolysis. Our data demonstrate that in active neurons, lactate is preferred to glucose as an energy substrate, and that lactate metabolism shapes neuronal activity in the neocortex through KATP channels. Our results highlight the importance of metabolic crosstalk between neurons and astrocytes for brain function.
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Affiliation(s)
- Anastassios Karagiannis
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Thierry Gallopin
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Alexandre Lacroix
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Fabrice Plaisier
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Juliette Piquet
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Hélène Geoffroy
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Régine Hepp
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Jérémie Naudé
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Benjamin Le Gac
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Richard Egger
- Institute for Neurophysiology, Goethe University FrankfurtFrankfurtGermany
| | - Bertrand Lambolez
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Dongdong Li
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
| | - Jean Rossier
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
- Brain Plasticity Unit, CNRS UMR 8249, CNRS, ESPCI ParisParisFrance
| | - Jochen F Staiger
- Institute for Neuroanatomy, University Medical Center Göttingen, Georg-August- University GöttingenGoettingenGermany
| | - Hiromi Imamura
- Graduate School of Biostudies, Kyoto UniversityKyotoJapan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of MedicineHyogoJapan
| | - Jochen Roeper
- Institute for Neurophysiology, Goethe University FrankfurtFrankfurtGermany
| | - Bruno Cauli
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS)ParisFrance
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7
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A O, U M, Lf B, A GC. Energy metabolism in childhood neurodevelopmental disorders. EBioMedicine 2021; 69:103474. [PMID: 34256347 PMCID: PMC8324816 DOI: 10.1016/j.ebiom.2021.103474] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/30/2021] [Accepted: 06/18/2021] [Indexed: 12/24/2022] Open
Abstract
Whereas energy function in the aging brain and their related neurodegenerative diseases has been explored in some detail, there is limited knowledge about molecular mechanisms and brain networks of energy metabolism during infancy and childhood. In this review we describe current insights on physiological brain energetics at prenatal and neonatal stages, and in childhood. We then describe the main groups of inborn errors of energy metabolism affecting the brain. Of note, scarce basic neuroscience research in this field limits the opportunity for these disorders to provide paradigms of energy utilization during neurodevelopment. Finally, we report energy metabolism disturbances in well-known non-metabolic neurodevelopmental disorders. As energy metabolism is a fundamental biological function, brain energy utilization is likely altered in most neuropediatric diseases. Precise knowledge on mechanisms of brain energy disturbance will open the possibility of metabolic modulation therapies regardless of disease etiology.
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Affiliation(s)
- Oyarzábal A
- Neurometabolic Unit and Laboratory of Synaptic Metabolism. IPR, CIBERER (ISCIII) and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Musokhranova U
- Neurometabolic Unit and Laboratory of Synaptic Metabolism. IPR, CIBERER (ISCIII) and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Barros Lf
- Center for Scientific Studies - CECs, Valdivia 5110466, Chile
| | - García-Cazorla A
- Neurometabolic Unit and Laboratory of Synaptic Metabolism. IPR, CIBERER (ISCIII) and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain.
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8
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Fitzgerald E, Roberts J, Tennant DA, Boardman JP, Drake AJ. Metabolic adaptations to hypoxia in the neonatal mouse forebrain can occur independently of the transporters SLC7A5 and SLC3A2. Sci Rep 2021; 11:9092. [PMID: 33907288 PMCID: PMC8079390 DOI: 10.1038/s41598-021-88757-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/16/2021] [Indexed: 02/02/2023] Open
Abstract
Neonatal encephalopathy due to hypoxia-ischemia is associated with adverse neurodevelopmental effects. The involvement of branched chain amino acids (BCAAs) in this is largely unexplored. Transport of BCAAs at the plasma membrane is facilitated by SLC7A5/SLC3A2, which increase with hypoxia. We hypothesized that hypoxia would alter BCAA transport and metabolism in the neonatal brain. We investigated this using an organotypic forebrain slice culture model with, the SLC7A5/SLC3A2 inhibitor, 2-Amino-2-norbornanecarboxylic acid (BCH) under normoxic or hypoxic conditions. We subsequently analysed the metabolome and candidate gene expression. Hypoxia was associated with increased expression of SLC7A5 and SLC3A2 and an increased tissue abundance of BCAAs. Incubation of slices with 13C-leucine confirmed that this was due to increased cellular uptake. BCH had little effect on metabolite abundance under normoxic or hypoxic conditions. This suggests hypoxia drives increased cellular uptake of BCAAs in the neonatal mouse forebrain, and membrane mediated transport through SLC7A5 and SLC3A2 is not essential for this process. This indicates mechanisms exist to generate the compounds required to maintain essential metabolism in the absence of external nutrient supply. Moreover, excess BCAAs have been associated with developmental delay, providing an unexplored mechanism of hypoxia mediated pathogenesis in the developing forebrain.
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Affiliation(s)
- Eamon Fitzgerald
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
| | - Jennie Roberts
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Daniel A Tennant
- Institute of Metabolism and Systems Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - James P Boardman
- MRC Centre for Reproductive Health, University of Edinburgh, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Amanda J Drake
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
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9
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Gul Z, Buyukuysal MC, Buyukuysal RL. Brain slice viability determined under normoxic and oxidative stress conditions: involvement of slice quantity in the medium. Neurol Res 2020; 42:228-238. [DOI: 10.1080/01616412.2020.1723299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Zulfiye Gul
- Department of Medical Pharmacology, Faculty of Medicine, Bahcesehir University, Istanbul, Turkey
| | - M. Cagatay Buyukuysal
- Department of Biostatistics, School of Medicine, Bulent Ecevit University, Zonguldak, Turkey
| | - R. Levent Buyukuysal
- Department of Medical Pharmacology, Faculty of Medicine, Uludag University, Bursa, Turkey
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10
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Pang R, Wang X, Du Z, Pei F, Li Z, Sun L, Wang S, Peng Y, Lu X, Gao X, Chang C. The distribution and density of monocarboxylate transporter 2 in cerebral cortex, hippocampus and cerebellum of wild-type mice. J Anat 2019; 236:370-377. [PMID: 31713246 DOI: 10.1111/joa.13099] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2019] [Indexed: 01/07/2023] Open
Abstract
Monocarboxylates cannot cross the blood-brain barrier freely to participate in brain energy metabolism. Specific monocarboxylate transporters (MCTs) are needed to cross cellular membranes. Monocarboxylate transporter 2 (MCT2) is a major monocarboxylate transporter encoded by the SLC16A7 gene. Recent studies reported that neurodegenerative diseases of the CNS, such as Alzheimer's disease (AD) and Parkinson's disease (PD), were related to energy metabolic impairment. MCT2 also plays an important role in energy metabolism in the CNS. To provide experimental evidence for future research on the role of MCT2 in the pathological process of CNS degenerative diseases, the distribution and density of MCT2 in different subregions of wild-type mouse brain was examined using immunohistochemistry, western blot and immunogold post-embedding electron microscopic techniques. The amount of MCT2 was higher in cerebellum than in cortex and hippocampus on western blots, and there was no statistical difference between cortex and hippocampus. Immunohistochemistry assay revealed the highest density of MCT2 in the CA3 of the hippocampus. The granular cell layer of the cerebellum contained more MCT2 than the molecular layer. The MCT2 density on the end feet of astrocytes of molecular layer was lower than in hippocampus, but the postsynaptic densities (PSDs) of asymmetric synapses in the molecular layer exhibited a high density using immunogold post-embedding electron microscopic techniques.
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Affiliation(s)
- Ruiqi Pang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaofan Wang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhiqiang Du
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Feifei Pei
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Zhiyue Li
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Libing Sun
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Shuying Wang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yingnan Peng
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xupeng Lu
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Xiaoqun Gao
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China.,Center of Cerebral Palsy Surgical Research and Treatment, Zhengzhou University, Zhengzhou, China.,Birth Defect Prevention Key Laboratory, National Health Commission of the People's Republic of China, Zhengzhou, China
| | - Cheng Chang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, China.,Center of Cerebral Palsy Surgical Research and Treatment, Zhengzhou University, Zhengzhou, China.,Birth Defect Prevention Key Laboratory, National Health Commission of the People's Republic of China, Zhengzhou, China
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11
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Richter J, Rabe D, Duysen K, Melchert UH, Oltmanns KM. Lactate infusion increases brain energy content during euglycemia but not hypoglycemia in healthy men. NMR IN BIOMEDICINE 2019; 32:e4167. [PMID: 31468650 DOI: 10.1002/nbm.4167] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 07/04/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
A special characteristic of the brain is the usage of lactate as alternative fuel instead of glucose to preserve its energy homeostasis. This physiological function is valid for sufficient cerebral glucose supply, as well as presumably during hypoglycemia, given that exogenous lactate infusion suppresses hormonal counterregulation. However, it is not yet clarified whether this effect is mediated by the use of lactate as an alternative cerebral energy substrate or any other mechanism. We hypothesized that under conditions of limited access to glucose (ie, during experimental hypoglycemia) lactate infusion would prevent hypoglycemia-induced neuroenergetic deficits in a neuroprotective way. In a randomized, double-blind, crossover study, lactate vs placebo infusion was compared during hyperinsulinemic-hypoglycemic clamps in 16 healthy young men. We measured the cerebral high-energy phosphate content - ie, adenosine triphosphate (ATP), phosphocreatine (PCr) and inorganic phosphate (Pi) levels - by 31 P-magnetic resonance spectroscopy as well as the neuroendocrine stress response. During euglycemia, lactate infusion increased ATP/Pi as well as PCr/Pi ratios compared with baseline values and placebo infusion. During hypoglycemia, there were no differences between the lactate and the placebo condition in both ratios. Hormonal counterregulation was significantly diminished upon lactate infusion. Our data demonstrate an elevated cerebral high-energy phosphate content upon lactate infusion during euglycemia, whereas there was no such effect during experimental hypoglycemia. Nevertheless, lactate infusion suppressed hypoglycemic hormonal counterregulation. Lactate thus adds to cerebral energy provision during euglycemia and may contribute to an increase in ATP reserves, which in turn protects the brain against neuroglucopenia under recurrent hypopglycemic conditions, eg, in diabetic patients.
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Affiliation(s)
- Juliane Richter
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Doerte Rabe
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kai Duysen
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Uwe H Melchert
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kerstin M Oltmanns
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
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Elolimy AA, Abdelmegeid MK, McCann JC, Shike DW, Loor JJ. Residual feed intake in beef cattle and its association with carcass traits, ruminal solid-fraction bacteria, and epithelium gene expression. J Anim Sci Biotechnol 2018; 9:67. [PMID: 30258628 PMCID: PMC6151901 DOI: 10.1186/s40104-018-0283-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 08/13/2018] [Indexed: 12/14/2022] Open
Abstract
Background Residual feed intake (RFI) describes an animal’s feed efficiency independent of growth performance. The objective of this study was to determine differences in growth performance, carcass traits, major bacteria attached to ruminal solids-fraction, and ruminal epithelium gene expression between the most-efficient and the least-efficient beef cattle. One-hundred and forty-nine Red Angus cattle were allocated to three contemporary groups according to sex and herd origin. Animals were fed a finishing diet in confinement for 70 d to determine the RFI category for each. Within each group, the two most-efficient (n = 6; RFI coefficient = − 2.69 ± 0.58 kg dry matter intake (DMI)/d) and the two least-efficient animals (n = 6; RFI coefficient = 3.08 ± 0.55 kg DMI/d) were selected. Immediately after slaughter, ruminal solids-fraction and ruminal epithelium were collected for bacteria relative abundance and epithelial gene expression analyses, respectively, using real-time PCR. Results The most-efficient animals consumed less feed (P = 0.01; 5.03 kg less DMI/d) compared with the least-efficient animals. No differences (P > 0.10) in initial body weight (BW), final BW, and average daily gain (ADG) were observed between the two RFI classes. There were no significant RFI × sex effects (P > 0.10) on growth performance. Compared with the least-efficient group, hot carcass weight (HCW), ribeye area (REA), and kidney, pelvic, and heart fat (KPH) were greater (P ≤ 0.05) in the most-efficient cattle. No RFI × sex effect (P > 0.10) for carcass traits was detected between RFI groups. Of the 10 bacterial species evaluated, the most-efficient compared with least efficient cattle had greater (P ≤ 0.05) relative abundance of Eubacterium ruminantium, Fibrobacter succinogenes, and Megasphaera elsdenii, and lower (P ≤ 0.05) Succinimonas amylolytica and total bacterial density. No RFI × sex effect on ruminal bacteria was detected between RFI groups. Of the 34 genes evaluated in ruminal epithelium, the most-efficient cattle had greater (P ≤ 0.05) abundance of genes involved in VFA absorption, metabolism, ketogenesis, and immune/inflammation-response. The RFI × sex interactions indicated that responses in gene expression between RFI groups were due to differences in sex. Steers in the most-efficient compared with least-efficient group had greater (P ≤ 0.05) expression of SLC9A1, HIF1A, and ACO2. The most-efficient compared with least-efficient heifers had greater (P ≤ 0.05) mRNA expression of BDH1 and lower expression (P ≤ 0.05) of SLC9A2 and PDHA1. Conclusions The present study revealed that greater feed efficiency in beef cattle is associated with differences in bacterial species and transcriptional adaptations in the ruminal epithelium that might enhance nutrient delivery and utilization by tissues. The lack of RFI × sex interaction for growth performance and carcass traits indicates that sex may not play a major role in improving these phenotypes in superior RFI beef cattle. However, it is important to note that this result should not be considered a solid biomarker of efficient beef cattle prior to further examination due to the limited number of heifers compared with steers used in the study. Electronic supplementary material The online version of this article (10.1186/s40104-018-0283-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ahmed A Elolimy
- 1Mammalian NutriPhysioGenomics, Department of Animal Sciences, University of Illinois, Urbana, IL USA.,2Department of Animal Sciences, University of Illinois, Urbana, IL USA
| | - Mohamed K Abdelmegeid
- 1Mammalian NutriPhysioGenomics, Department of Animal Sciences, University of Illinois, Urbana, IL USA.,2Department of Animal Sciences, University of Illinois, Urbana, IL USA.,3Faculty of Veterinary Medicine, Kafrelsheikh University, Kafr El-Shaikh, 33516 Egypt
| | - Joshua C McCann
- 2Department of Animal Sciences, University of Illinois, Urbana, IL USA
| | - Daniel W Shike
- 2Department of Animal Sciences, University of Illinois, Urbana, IL USA
| | - Juan J Loor
- 1Mammalian NutriPhysioGenomics, Department of Animal Sciences, University of Illinois, Urbana, IL USA.,2Department of Animal Sciences, University of Illinois, Urbana, IL USA.,4Division of Nutritional Sciences, Illinois Informatics Institute, University of Illinois, Urbana, IL USA
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Reality of Inhibitory GABA in Neonatal Brain: Time to Rewrite the Textbooks? J Neurosci 2018; 36:10242-10244. [PMID: 27707962 DOI: 10.1523/jneurosci.2270-16.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 08/26/2016] [Indexed: 12/30/2022] Open
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Datta S, Chakrabarti N. Age related rise in lactate and its correlation with lactate dehydrogenase (LDH) status in post-mitochondrial fractions isolated from different regions of brain in mice. Neurochem Int 2018; 118:23-33. [PMID: 29678731 DOI: 10.1016/j.neuint.2018.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/11/2018] [Accepted: 04/11/2018] [Indexed: 02/06/2023]
Abstract
Rise in brain lactate is the hallmark of ageing. Separate studies report that ageing is associated with elevation of lactate level and alterations of lactate dehydrogenase (LDH)-A/B mRNA-expression-ratio in cerebral cortex and hippocampus. However, age related lactate rise in brain and its association with LDH status and their brain regional variations are still elusive. In the present study, level of lactate, LDH (A and B) activity and LDH-A expression were evaluated in post-mitochondrial fraction of tissues isolated from four different brain regions (cerebral cortex, hippocampus, substantia nigra and cerebellum) of young and aged mice. Lactate levels elevated in four brain regions with maximum rise in substantia nigra of aged mice. LDH-A protein expression and its activity decreased in cerebral cortex, hippocampus and substantia nigra without any changes of these parameters in cerebellum of aged mice. LDH-B activity decreased in hippocampus, substantia nigra and cerebellum whereas its activity remains unaltered in cerebral cortex of aged mice. Accordingly, the ratio of LDH-A/LDH-B-activity remains unaltered in hippocampus and substantia nigra, decreased in cerebral cortex and increased in cerebellum. Therefore, rise of lactate in three brain regions (cerebral cortex, hippocampus, substantia nigra) appeared to be not correlated with the alterations of its regulatory enzymes activities in these three brain regions, rather it supports the fact of involvement of other mechanisms, like lactate transport and/or aerobic/anaerobic metabolism as the possible cause(s) of lactate rise in these three brain regions. The increase in LDH-A/LDH-B-activity-ratio appeared to be positively correlated with elevated lactate level in cerebellum of aged mice. Overall, the present study indicates that the mechanism of rise in lactate in brain varies with brain regions where LDH status plays an important role during ageing.
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Affiliation(s)
- Siddhartha Datta
- Department of Physiology, University of Calcutta, Kolkata, West Bengal, India; UGC-CPEPA Centre for "Electro-physiological and Neuro-imaging Studies Including Mathematical Modelling", University of Calcutta, Kolkata, West Bengal, India.
| | - Nilkanta Chakrabarti
- Department of Physiology, University of Calcutta, Kolkata, West Bengal, India; UGC-CPEPA Centre for "Electro-physiological and Neuro-imaging Studies Including Mathematical Modelling", University of Calcutta, Kolkata, West Bengal, India; S. N. Pradhan Centre for Neurosciences, University of Calcutta, Kolkata, West Bengal, India.
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Contribution of Intrinsic Lactate to Maintenance of Seizure Activity in Neocortical Slices from Patients with Temporal Lobe Epilepsy and in Rat Entorhinal Cortex. Int J Mol Sci 2017; 18:ijms18091835. [PMID: 28832554 PMCID: PMC5618484 DOI: 10.3390/ijms18091835] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 12/20/2022] Open
Abstract
Neuronal lactate uptake supports energy metabolism associated with synaptic signaling and recovery of extracellular ion gradients following neuronal activation. Altered expression of the monocarboxylate transporters (MCT) in temporal lobe epilepsy (TLE) hampers lactate removal into the bloodstream. The resulting increase in parenchymal lactate levels might exert both, anti- and pro-ictogen effects, by causing acidosis and by supplementing energy metabolism, respectively. Hence, we assessed the contribution of lactate to the maintenance of transmembrane potassium gradients, synaptic signaling and pathological network activity in chronic epileptic human tissue. Stimulus induced and spontaneous field potentials and extracellular potassium concentration changes (∆[K⁺]O) were recorded in parallel with tissue pO₂ and pH in slices from TLE patients while blocking MCTs by α-cyano-4-hydroxycinnamic acid (4-CIN) or d-lactate. Intrinsic lactate contributed to the oxidative energy metabolism in chronic epileptic tissue as revealed by the changes in pO₂ following blockade of lactate uptake. However, unlike the results in rat hippocampus, ∆[K⁺]O recovery kinetics and field potential amplitude did not depend on the presence of lactate. Remarkably, inhibition of lactate uptake exerted pH-independent anti-seizure effects both in healthy rat and chronic epileptic tissue and this effect was partly mediated via adenosine 1 receptor activation following decreased oxidative metabolism.
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Abstract
Intracellular accumulation of abnormally phosphorylated tau in different types of neurons is a pathological characteristic of Alzheimer's disease (AD). While tau modification and associated neuronal loss and hypometabolism start in the entorhinal cortex (EC) in early AD patients, the mechanism by which mutant P301L hTau leads to dementia is not fully elucidated. Here, we studied the effects of P301L hTau transduction in the medial EC (MEC) of mice on tau phosphorylation and accumulation, and cognitive deficit. We found that the exogenous mutant tau protein was restricted in MEC without spreading to other brain regions at one month after transduction. Interestingly, expression of the mutant tau in MEC induces endogenous tau hyperphosphorylation and accumulation in hippocampus and cortex, and inhibits neuronal activity with attenuated PP-DG synapse plasticity, leading to hippocampus-dependent memory deficit with intact olfactory function. These findings suggest a novel neuropathological mechanism of early AD, which is initiated by tau accumulation in MEC, and demonstrate a tau pathological model of early stage AD.
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Sigalas C, Konsolaki E, Skaliora I. Sex differences in endogenous cortical network activity: spontaneously recurring Up/Down states. Biol Sex Differ 2017; 8:21. [PMID: 28630662 PMCID: PMC5471918 DOI: 10.1186/s13293-017-0143-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 06/06/2017] [Indexed: 03/02/2023] Open
Abstract
BACKGROUND Several molecular and cellular processes in the vertebrate brain exhibit differences between males and females, leading to sexual dimorphism in the formation of neural circuits and brain organization. While studies on large-scale brain networks provide ample evidence for both structural and functional sex differences, smaller-scale local networks have remained largely unexplored. In the current study, we investigate sexual dimorphism in cortical dynamics by means of spontaneous Up/Down states, a type of network activity that is exhibited during slow-wave sleep, quiet wakefulness, and anesthesia and is thought to represent the default activity of the cortex. METHODS Up state activity was monitored by local field potential recordings in coronal brain slices of male and female mice across three ages with distinct secretion profiles of sex hormones: (i) pre-puberty (17-21 days old), (ii) 3-9 adult (months old), and (iii) old (19-24 months old). RESULTS Female mice of all ages exhibited longer and more frequent Up states compared to aged-matched male mice. Power spectrum analysis revealed sex differences in the relative power of Up state events, with female mice showing reduced power in the delta range (1-4 Hz) and increased power in the theta range (4-8 Hz) compared to male mice. No sex differences were found in the characteristics of Up state peak voltage and latency. CONCLUSIONS The present study revealed for the first time sex differences in intracortical network activity, using an ex vivo paradigm of spontaneously occurring Up/Down states. We report significant sex differences in Up state properties that are already present in pre-puberty animals and are maintained through adulthood and old age.
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Affiliation(s)
- Charalambos Sigalas
- Neurophysiology Laboratory, Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efessiou Street, Athens, 115 27 Greece
| | - Eleni Konsolaki
- Psychology Department, Deree - The American College of Greece, Athens, 153 42 Greece
| | - Irini Skaliora
- Neurophysiology Laboratory, Centre for Basic Research, Biomedical Research Foundation of the Academy of Athens, 4 Soranou Efessiou Street, Athens, 115 27 Greece
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Porte B, Chatelain C, Hardouin J, Derambure C, Zerdoumi Y, Hauchecorne M, Dupré N, Bekri S, Gonzalez B, Marret S, Cosette P, Leroux P. Proteomic and transcriptomic study of brain microvessels in neonatal and adult mice. PLoS One 2017; 12:e0171048. [PMID: 28141873 PMCID: PMC5283732 DOI: 10.1371/journal.pone.0171048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/13/2017] [Indexed: 12/17/2022] Open
Abstract
Infants born before 29 weeks gestation incur a major risk of preterm encephalopathy and subependymal/intracerebral/intraventricular haemorrhage. In mice, an ontogenic window of haemorrhage risk was recorded up to 5 days after birth in serpine1 knock-out animals. Using proteome and transcriptome approaches in mouse forebrain microvessels, we previously described the remodelling of extracellular matrix and integrins likely strengthening the vascular wall between postnatal day 5 (P5) and P10. Haemorrhage is the ultimate outcome of vessel damage (i.e., during ischaemia), although discreet vessel insults may be involved in the aetiology of preterm encephalopathy. In this study, we examined proteins identified by mass spectrometry and segregating in gene ontology pathways in forebrain microvessels in P5, P10, and adult wild type mice. In parallel, comparative transcript levels were obtained using RNA hybridization microarrays and enriched biological pathways were extracted from genes exhibiting at least a two-fold change in expression. Five major biological functions were observed in those genes detected both as proteins and mRNA expression undergoing at least a two-fold change in expression in one or more age comparisons: energy metabolism, protein metabolism, antioxidant function, ion exchanges, and transport. Adult microvessels exhibited the highest protein and mRNA expression levels for a majority of genes. Energy metabolism-enriched gene ontology pathways pointed to the preferential occurrence of glycolysis in P5 microvessels cells versus P10 and adult preparations enriched in aerobic oxidative enzymes. Age-dependent levels of RNA coding transport proteins at the plasma membrane and mitochondria strengthened our findings based on protein data. The data suggest that immature microvessels have fewer energy supply alternatives to glycolysis than mature structures. In the context of high energy demand, this constraint might account for vascular damage and maintenance of the high bleeding occurrence in specific areas in immature brain.
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Affiliation(s)
- Baptiste Porte
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
| | - Clémence Chatelain
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
| | - Julie Hardouin
- Normandie Université, UNIROUEN, UMR-6270, CNRS, IRIB, Mont-Saint-Aignan, France
- Normandie Université, UNIROUEN, Proteomic Facility PISSARO, IRIB, Mont-Saint-Aignan, France
| | - Céline Derambure
- Normandie Université, UNIROUEN, UMR-S905, INSERM, IRIB, Rouen, France
| | - Yasmine Zerdoumi
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
| | - Michèle Hauchecorne
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
| | - Nicolas Dupré
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
| | - Soumeya Bekri
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
- Metabolic Biochemistry Department, Rouen University Hospital, Rouen, France
| | - Bruno Gonzalez
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
| | - Stéphane Marret
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
- Neonatal Pediatrics and Intensive Care Department, Rouen University Hospital, Rouen, France
| | - Pascal Cosette
- Normandie Université, UNIROUEN, UMR-6270, CNRS, IRIB, Mont-Saint-Aignan, France
- Normandie Université, UNIROUEN, Proteomic Facility PISSARO, IRIB, Mont-Saint-Aignan, France
| | - Philippe Leroux
- Normandie Université, UNIROUEN, U1245, INSERM, Institute for Research and Innovation in Biomedicine (IRIB), Rouen, France
- * E-mail:
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Differential Presynaptic ATP Supply for Basal and High-Demand Transmission. J Neurosci 2017; 37:1888-1899. [PMID: 28093477 DOI: 10.1523/jneurosci.2712-16.2017] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/21/2022] Open
Abstract
The relative contributions of glycolysis and oxidative phosphorylation to neuronal presynaptic energy demands are unclear. In rat hippocampal neurons, ATP production by either glycolysis or oxidative phosphorylation alone sustained basal evoked synaptic transmission for up to 20 min. However, combined inhibition of both ATP sources abolished evoked transmission. Neither action potential propagation failure nor depressed Ca2+ influx explained loss of evoked synaptic transmission. Rather, inhibition of ATP synthesis caused massive spontaneous vesicle exocytosis, followed by arrested endocytosis, accounting for the disappearance of evoked postsynaptic currents. In contrast to its weak effects on basal transmission, inhibition of oxidative phosphorylation alone depressed recovery from vesicle depletion. Local astrocytic lactate shuttling was not required. Instead, either ambient monocarboxylates or neuronal glycolysis was sufficient to supply requisite substrate. In summary, basal transmission can be sustained by glycolysis, but strong presynaptic demands are met preferentially by oxidative phosphorylation, which can be maintained by bulk but not local monocarboxylates or by neuronal glycolysis.SIGNIFICANCE STATEMENT Neuronal energy levels are critical for proper CNS function, but the relative roles for the two main sources of ATP production, glycolysis and oxidative phosphorylation, in fueling presynaptic function in unclear. Either glycolysis or oxidative phosphorylation can fuel low-frequency synaptic function and inhibiting both underlies loss of synaptic transmission via massive vesicle release and subsequent failure to endocytose lost vesicles. Oxidative phosphorylation, fueled by either glycolysis or endogenously released monocarboxylates, can fuel more metabolically demanding tasks such as vesicle recovery after depletion. Our work demonstrates the flexible nature of fueling presynaptic function to maintain synaptic function.
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O'Shea E, Waters SM, Keogh K, Kelly AK, Kenny DA. Examination of the molecular control of ruminal epithelial function in response to dietary restriction and subsequent compensatory growth in cattle. J Anim Sci Biotechnol 2016; 7:53. [PMID: 27651894 PMCID: PMC5025635 DOI: 10.1186/s40104-016-0114-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 08/31/2016] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND The objective of this study was to investigate the effect of dietary restriction and subsequent compensatory growth on the relative expression of genes involved in volatile fatty acid transport, metabolism and cell proliferation in ruminal epithelial tissue of beef cattle. Sixty Holstein Friesian bulls (mean liveweight 370 ± 35 kg; mean age 479 ± 15 d) were assigned to one of two groups: (i) restricted feed allowance (RES; n = 30) for 125 d (Period 1) followed by ad libitum access to feed for 55 d (Period 2) or (ii) ad libitum access to feed throughout (ADLIB; n = 30). Target growth rate for RES was 0.6 kg/d during Period 1. At the end of each dietary period, 15 animals from each treatment group were slaughtered and ruminal epithelial tissue and liquid digesta harvested from the ventral sac of the rumen. Real-time qPCR was used to quantify mRNA transcripts of 26 genes associated with ruminal epithelial function. Volatile fatty acid analysis of rumen fluid from individual animals was conducted using gas chromatography. RESULTS Diet × period interactions were evident for genes involved in ketogenesis (BDH2, P = 0.017), pyruvate metabolism (LDHa, P = 0.048; PDHA1, P = 0.015) and cellular transport and structure (DSG1, P = 0.019; CACT, P = 0.027). Ruminal concentrations of propionic acid (P = 0.018) and n-valeric acid (P = 0.029) were lower in RES animals, compared with ADLIB, throughout the experiment. There was also a strong tendency (P = 0.064) toward a diet × period interaction for n-butyric with higher concentrations in RES animals, compared with ADLIB, during Period 1. CONCLUSIONS These data suggest that following nutrient restriction, the structural integrity of the rumen wall is compromised and there is upregulation of genes involved in the production of ketone bodies and breakdown of pyruvate for cellular energy. These results provide an insight into the potential molecular mechanisms regulating ruminal epithelial absorptive metabolism and growth following nutrient restriction and subsequent compensatory growth.
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Affiliation(s)
- Emma O'Shea
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, 4 Ireland ; Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc Grange, Dunsany, Co. Meath, Ireland ; UCD Earth Institute, University College Dublin, Belfield, Dublin, 4 Ireland
| | - Sinéad M Waters
- Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc Grange, Dunsany, Co. Meath, Ireland
| | - Kate Keogh
- Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc Grange, Dunsany, Co. Meath, Ireland
| | - Alan K Kelly
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, 4 Ireland
| | - David A Kenny
- School of Agriculture and Food Science, University College Dublin, Belfield, Dublin, 4 Ireland ; Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc Grange, Dunsany, Co. Meath, Ireland
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Kann O, Hollnagel JO, Elzoheiry S, Schneider J. Energy and Potassium Ion Homeostasis during Gamma Oscillations. Front Mol Neurosci 2016; 9:47. [PMID: 27378847 PMCID: PMC4909733 DOI: 10.3389/fnmol.2016.00047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/30/2016] [Indexed: 12/21/2022] Open
Abstract
Fast neuronal network oscillations in the gamma frequency band (30-100 Hz) occur in various cortex regions, require timed synaptic excitation and inhibition with glutamate and GABA, respectively, and are associated with higher brain functions such as sensory perception, attentional selection and memory formation. However, little is known about energy and ion homeostasis during the gamma oscillation. Recent studies addressed this topic in slices of the rodent hippocampus using cholinergic and glutamatergic receptor models of gamma oscillations (GAM). Methods with high spatial and temporal resolution were applied in vitro, such as electrophysiological recordings of local field potential (LFP) and extracellular potassium concentration ([K(+)]o), live-cell fluorescence imaging of nicotinamide adenine dinucleotide (phosphate) and flavin adenine dinucleotide [NAD(P)H and FAD, respectively] (cellular redox state), and monitoring of the interstitial partial oxygen pressure (pO2) in depth profiles with microsensor electrodes, including mathematical modeling. The main findings are: (i) GAM are associated with high oxygen consumption rate and significant changes in the cellular redox state, indicating rapid adaptations in glycolysis and oxidative phosphorylation; (ii) GAM are accompanied by fluctuating elevations in [K(+)]o of less than 0.5 mmol/L from baseline, likely reflecting effective K(+)-uptake mechanisms of neuron and astrocyte compartments; and (iii) GAM are exquisitely sensitive to metabolic stress induced by lowering oxygen availability or by pharmacological inhibition of the mitochondrial respiratory chain. These findings reflect precise cellular adaptations to maintain adenosine-5'-triphosphate (ATP), ion and neurotransmitter homeostasis and thus neural excitability and synaptic signaling during GAM. Conversely, the exquisite sensitivity of GAM to metabolic stress might significantly contribute the exceptional vulnerability of higher brain functions in brain disease.
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Affiliation(s)
- Oliver Kann
- Institute of Physiology and Pathophysiology, University of HeidelbergHeidelberg, Germany; Interdisciplinary Center for Neurosciences (IZN), University of HeidelbergHeidelberg, Germany
| | - Jan-Oliver Hollnagel
- Institute of Physiology and Pathophysiology, University of HeidelbergHeidelberg, Germany; Interdisciplinary Center for Neurosciences (IZN), University of HeidelbergHeidelberg, Germany
| | - Shehabeldin Elzoheiry
- Institute of Physiology and Pathophysiology, University of HeidelbergHeidelberg, Germany; Interdisciplinary Center for Neurosciences (IZN), University of HeidelbergHeidelberg, Germany
| | - Justus Schneider
- Institute of Physiology and Pathophysiology, University of HeidelbergHeidelberg, Germany; Interdisciplinary Center for Neurosciences (IZN), University of HeidelbergHeidelberg, Germany
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Magistretti PJ, Allaman I. A cellular perspective on brain energy metabolism and functional imaging. Neuron 2015; 86:883-901. [PMID: 25996133 DOI: 10.1016/j.neuron.2015.03.035] [Citation(s) in RCA: 752] [Impact Index Per Article: 83.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The energy demands of the brain are high: they account for at least 20% of the body's energy consumption. Evolutionary studies indicate that the emergence of higher cognitive functions in humans is associated with an increased glucose utilization and expression of energy metabolism genes. Functional brain imaging techniques such as fMRI and PET, which are widely used in human neuroscience studies, detect signals that monitor energy delivery and use in register with neuronal activity. Recent technological advances in metabolic studies with cellular resolution have afforded decisive insights into the understanding of the cellular and molecular bases of the coupling between neuronal activity and energy metabolism and point at a key role of neuron-astrocyte metabolic interactions. This article reviews some of the most salient features emerging from recent studies and aims at providing an integration of brain energy metabolism across resolution scales.
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Affiliation(s)
- Pierre J Magistretti
- Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia; Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland; Center for Psychiatric Neurosciences, Department of Psychiatry, University of Lausanne, Lausanne 1008, Switzerland.
| | - Igor Allaman
- Laboratory of Neuroenergetics and Cellular Dynamics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne 1015, Switzerland
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Affiliation(s)
- Chang-Hoon Cho
- School of Biosystem and Biomedical Science, College of Health Science, Korea University Seoul, South Korea
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Schneider J, Lewen A, Ta TT, Galow LV, Isola R, Papageorgiou IE, Kann O. A reliable model for gamma oscillations in hippocampal tissue. J Neurosci Res 2015; 93:1067-78. [PMID: 25808046 DOI: 10.1002/jnr.23590] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 02/16/2015] [Accepted: 02/27/2015] [Indexed: 12/13/2022]
Abstract
Gamma oscillations (30-100 Hz) reflect a fast brain rhythm that provides a fundamental mechanism of complex neuronal information processing in the hippocampus and in the neocortex in vivo. Gamma oscillations have been implicated in higher brain functions, such as sensory perception, motor activity, and memory formation. Experimental studies on synaptic transmission and bioenergetics underlying gamma oscillations have primarily used acute slices of the hippocampus. This study tests whether organotypic hippocampal slice cultures of the rat provide an alternative model for cortical gamma oscillations in vitro. Our findings are that 1) slice cultures feature well-preserved laminated architecture and neuronal morphology; 2) slice cultures of different maturation stages (7-28 days in vitro) reliably express gamma oscillations at about 40 Hz as induced by cholinergic (acetylcholine) or glutamatergic (kainate) receptor agonists; 3) the peak frequency of gamma oscillations depends on the temperature, with an increase of ∼ 3.5 Hz per degree Celsius for the range of 28-36 °C; 4) most slice cultures show persistent gamma oscillations for ∼ 1 hr during electrophysiological local field potential recordings, and later alterations may occur; and 5) in slice cultures, glucose at a concentration of 5 mM in the recording solution is sufficient to power gamma oscillations, and additional energy substrate supply with monocarboxylate metabolite lactate (2 mM) exclusively increases the peak frequency by ∼ 4 Hz. This study shows that organotypic hippocampal slice cultures provide a reliable model to study agonist-induced gamma oscillations at glucose levels near the physiological range.
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Affiliation(s)
- Justus Schneider
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Andrea Lewen
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Thuy-Truc Ta
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Lukas V Galow
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Raffaella Isola
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Ismini E Papageorgiou
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany
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Galow LV, Schneider J, Lewen A, Ta TT, Papageorgiou IE, Kann O. Energy substrates that fuel fast neuronal network oscillations. Front Neurosci 2014; 8:398. [PMID: 25538552 PMCID: PMC4256998 DOI: 10.3389/fnins.2014.00398] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 11/18/2014] [Indexed: 01/03/2023] Open
Abstract
Fast neuronal network oscillations in the gamma-frequency band (30–−100 Hz) provide a fundamental mechanism of complex neuronal information processing in the hippocampus and neocortex of mammals. Gamma oscillations have been implicated in higher brain functions such as sensory perception, motor activity, and memory formation. The oscillations emerge from precise synapse interactions between excitatory principal neurons such as pyramidal cells and inhibitory GABAergic interneurons, and they are associated with high energy expenditure. However, both energy substrates and metabolic pathways that are capable to power cortical gamma oscillations have been less defined. Here, we investigated the energy sources fueling persistent gamma oscillations in the CA3 subfield of organotypic hippocampal slice cultures of the rat. This preparation permits superior oxygen supply as well as fast application of glucose, glycolytic metabolites or drugs such as glycogen phosphorylase inhibitor during extracellular recordings of the local field potential. Our findings are: (i) gamma oscillations persist in the presence of glucose (10 mmol/L) for greater than 60 min in slice cultures while (ii) lowering glucose levels (2.5 mmol/L) significantly reduces the amplitude of the oscillation. (iii) Gamma oscillations are absent at low concentration of lactate (2 mmol/L). (iv) Gamma oscillations persist at high concentration (20 mmol/L) of either lactate or pyruvate, albeit showing significant reductions in the amplitude. (v) The breakdown of glycogen significantly delays the decay of gamma oscillations during glucose deprivation. However, when glucose is present, the turnover of glycogen is not essential to sustain gamma oscillations. Our study shows that fast neuronal network oscillations can be fueled by different energy-rich substrates, with glucose being most effective.
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Affiliation(s)
- Lukas V Galow
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg Heidelberg, Germany
| | - Justus Schneider
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg Heidelberg, Germany
| | - Andrea Lewen
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg Heidelberg, Germany
| | - Thuy-Truc Ta
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg Heidelberg, Germany
| | - Ismini E Papageorgiou
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg Heidelberg, Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg Heidelberg, Germany
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26
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Reid CA, Mullen S, Kim TH, Petrou S. Epilepsy, energy deficiency and new therapeutic approaches including diet. Pharmacol Ther 2014; 144:192-201. [PMID: 24924701 DOI: 10.1016/j.pharmthera.2014.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 05/28/2014] [Indexed: 02/08/2023]
Abstract
Metabolic dysfunction leading to epilepsy is well recognised. Dietary therapy, in particular the ketogenic diet, is now considered an effective option. Recent genetic studies have highlighted the central role that metabolism can play in setting seizure susceptibility. Here we discuss various metabolic disorders implicated in epilepsy focusing on energy deficiency due to genetic and environmental causes. We argue that low, uncompensated brain glucose levels can precipitate seizures. We will also explore mechanisms of disease and therapy in an attempt to identify common metabolic pathways involved in modulating seizure susceptibility. Finally, newer therapeutic approaches based on diet manipulation in the context of energy deficiency are discussed.
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Affiliation(s)
- Christopher A Reid
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia.
| | - Saul Mullen
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Tae Hwan Kim
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Steven Petrou
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia; Centre for Neural Engineering, The University of Melbourne, Parkville, Melbourne, Australia; Department of Electrical Engineering, The University of Melbourne, Parkville, Melbourne, Australia
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27
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Glycolysis and oxidative phosphorylation in neurons and astrocytes during network activity in hippocampal slices. J Cereb Blood Flow Metab 2014; 34:397-407. [PMID: 24326389 PMCID: PMC3948126 DOI: 10.1038/jcbfm.2013.222] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 11/12/2013] [Accepted: 11/13/2013] [Indexed: 12/14/2022]
Abstract
Network activation triggers a significant energy metabolism increase in both neurons and astrocytes. Questions of the primary neuronal energy substrate (e.g., glucose vs. lactate) as well as the relative contributions of glycolysis and oxidative phosphorylation and their cellular origin (neurons vs. astrocytes) are still a matter of debates. Using simultaneous measurements of electrophysiological and metabolic parameters during synaptic stimulation in hippocampal slices from mature mice, we show that neurons and astrocytes use both glycolysis and oxidative phosphorylation to meet their energy demands. Supplementation or replacement of glucose in artificial cerebrospinal fluid (ACSF) with pyruvate or lactate strongly modifies parameters related to network activity-triggered energy metabolism. These effects are not induced by changes in ATP content, pH(i), [Ca(2+)](i) or accumulation of reactive oxygen species. Our results suggest that during network activation, a significant fraction of NAD(P)H response (its overshoot phase) corresponds to glycolysis and the changes in cytosolic NAD(P)H and mitochondrial FAD are coupled. Our data do not support the hypothesis of a preferential utilization of astrocyte-released lactate by neurons during network activation in slices--instead, we show that during such activity glucose is an effective energy substrate for both neurons and astrocytes.
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28
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Álvarez Z, Mateos-Timoneda MA, Hyroššová P, Castaño O, Planell JA, Perales JC, Engel E, Alcántara S. The effect of the composition of PLA films and lactate release on glial and neuronal maturation and the maintenance of the neuronal progenitor niche. Biomaterials 2013; 34:2221-33. [DOI: 10.1016/j.biomaterials.2012.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 12/09/2012] [Indexed: 12/12/2022]
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29
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Zilberter M, Ivanov A, Ziyatdinova S, Mukhtarov M, Malkov A, Alpár A, Tortoriello G, Botting CH, Fülöp L, Osypov AA, Pitkänen A, Tanila H, Harkany T, Zilberter Y. Dietary energy substrates reverse early neuronal hyperactivity in a mouse model of Alzheimer's disease. J Neurochem 2013; 125:157-71. [PMID: 23241062 DOI: 10.1111/jnc.12127] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/10/2012] [Accepted: 12/11/2012] [Indexed: 01/25/2023]
Abstract
Deficient energy metabolism and network hyperactivity are the early symptoms of Alzheimer's disease (AD). In this study, we show that administration of exogenous oxidative energy substrates (OES) corrects neuronal energy supply deficiency that reduces the amyloid-beta-induced abnormal neuronal activity in vitro and the epileptic phenotype in AD model in vivo. In vitro, acute application of protofibrillar amyloid-β1-42 (Aβ1-42) induced aberrant network activity in wild-type hippocampal slices that was underlain by depolarization of both the neuronal resting membrane potential and GABA-mediated current reversal potential. Aβ1-42 also impaired synaptic function and long-term potentiation. These changes were paralleled by clear indications of impaired energy metabolism, as indicated by abnormal NAD(P)H signaling induced by network activity. However, when glucose was supplemented with OES pyruvate and 3-beta-hydroxybutyrate, Aβ1-42 failed to induce detrimental changes in any of the above parameters. We administered the same OES as chronic supplementation to a standard diet to APPswe/PS1dE9 transgenic mice displaying AD-related epilepsy phenotype. In the ex-vivo slices, we found neuronal subpopulations with significantly depolarized resting and GABA-mediated current reversal potentials, mirroring abnormalities we observed under acute Aβ1-42 application. Ex-vivo cortex of transgenic mice fed with standard diet displayed signs of impaired energy metabolism, such as abnormal NAD(P)H signaling and strongly reduced tolerance to hypoglycemia. Transgenic mice also possessed brain glycogen levels twofold lower than those of wild-type mice. However, none of the above neuronal and metabolic dysfunctions were observed in transgenic mice fed with the OES-enriched diet. In vivo, dietary OES supplementation abated neuronal hyperexcitability, as the frequency of both epileptiform discharges and spikes was strongly decreased in the APPswe/PS1dE9 mice placed on the diet. Altogether, our results suggest that early AD-related neuronal malfunctions underlying hyperexcitability and energy metabolism deficiency can be prevented by dietary supplementation with native energy substrates.
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Affiliation(s)
- Misha Zilberter
- Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
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30
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Potassium aspartate attenuates apoptotic cell death after focal cerebral ischemia in rats. ACTA ACUST UNITED AC 2013. [DOI: 10.1016/j.biomag.2012.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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31
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Mahan VL. Neuroprotective, neurotherapeutic, and neurometabolic effects of carbon monoxide. Med Gas Res 2012; 2:32. [PMID: 23270619 PMCID: PMC3599315 DOI: 10.1186/2045-9912-2-32] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 12/04/2012] [Indexed: 12/22/2022] Open
Abstract
Studies in animal models show that the primary mechanism by which heme-oxygenases impart beneficial effects is due to the gaseous molecule carbon monoxide (CO). Produced in humans mainly by the catabolism of heme by heme-oxygenase, CO is a neurotransmitter important for multiple neurologic functions and affects several intracellular pathways as a regulatory molecule. Exogenous administration of inhaled CO or carbon monoxide releasing molecules (CORM’s) impart similar neurophysiological responses as the endogenous gas. Its’ involvement in important neuronal functions suggests that regulation of CO synthesis and biochemical properties may be clinically relevant to neuroprotection and the key may be a change in metabolic substrate from glucose to lactate. Currently, the drug is under development as a therapeutic agent and safety studies in humans evaluating the safety and tolerability of inhaled doses of CO show no clinically important abnormalities, effects, or changes over time in laboratory safety variables. As an important therapeutic option, inhaled CO has entered clinical trials and its clinical role as a neuroprotective and neurotherapeutic agent has been suggested. In this article, we review the neuroprotective effects of endogenous CO and discuss exogenous CO as a neuroprotective and neurotherapeutic agent.
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Affiliation(s)
- Vicki L Mahan
- St, Christopher's Hospital for Children, Department of Pediatric Cardiothoracic Surgery, 3601 A Street, Philadelphia, PA, 19134, USA.
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32
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Lutas A, Yellen G. The ketogenic diet: metabolic influences on brain excitability and epilepsy. Trends Neurosci 2012; 36:32-40. [PMID: 23228828 DOI: 10.1016/j.tins.2012.11.005] [Citation(s) in RCA: 222] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 11/13/2012] [Accepted: 11/13/2012] [Indexed: 12/25/2022]
Abstract
A dietary therapy for pediatric epilepsy known as the ketogenic diet has seen a revival in its clinical use during the past decade. Although the underlying mechanism of the diet remains unknown, modern scientific approaches, such as the genetic disruption of glucose metabolism, are allowing for more detailed questions to be addressed. Recent work indicates that several mechanisms may exist for the ketogenic diet, including disruption of glutamatergic synaptic transmission, inhibition of glycolysis, and activation of ATP-sensitive potassium channels. Here, we describe on-going work in these areas that is providing a better understanding of metabolic influences on brain excitability and epilepsy.
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Affiliation(s)
- Andrew Lutas
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
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33
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Ben-Ari Y, Woodin MA, Sernagor E, Cancedda L, Vinay L, Rivera C, Legendre P, Luhmann HJ, Bordey A, Wenner P, Fukuda A, van den Pol AN, Gaiarsa JL, Cherubini E. Refuting the challenges of the developmental shift of polarity of GABA actions: GABA more exciting than ever! Front Cell Neurosci 2012; 6:35. [PMID: 22973192 PMCID: PMC3428604 DOI: 10.3389/fncel.2012.00035] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/29/2012] [Indexed: 12/12/2022] Open
Abstract
During brain development, there is a progressive reduction of intracellular chloride associated with a shift in GABA polarity: GABA depolarizes and occasionally excites immature neurons, subsequently hyperpolarizing them at later stages of development. This sequence, which has been observed in a wide range of animal species, brain structures and preparations, is thought to play an important role in activity-dependent formation and modulation of functional circuits. This sequence has also been considerably reinforced recently with new data pointing to an evolutionary preserved rule. In a recent “Hypothesis and Theory Article,” the excitatory action of GABA in early brain development is suggested to be “an experimental artefact” (Bregestovski and Bernard, 2012). The authors suggest that the excitatory action of GABA is due to an inadequate/insufficient energy supply in glucose-perfused slices and/or to the damage produced by the slicing procedure. However, these observations have been repeatedly contradicted by many groups and are inconsistent with a large body of evidence including the fact that the developmental shift is neither restricted to slices nor to rodents. We summarize the overwhelming evidence in support of both excitatory GABA during development, and the implications this has in developmental neurobiology.
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Affiliation(s)
- Yehezkel Ben-Ari
- INSERM Unité 901, Université de la Méditerranée, UMR S901 Aix-Marseille 2 and INMED Marseille, France
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34
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Pellerin L, Magistretti PJ. Sweet sixteen for ANLS. J Cereb Blood Flow Metab 2012; 32:1152-66. [PMID: 22027938 PMCID: PMC3390819 DOI: 10.1038/jcbfm.2011.149] [Citation(s) in RCA: 501] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 08/24/2011] [Accepted: 09/22/2011] [Indexed: 02/03/2023]
Abstract
Since its introduction 16 years ago, the astrocyte-neuron lactate shuttle (ANLS) model has profoundly modified our understanding of neuroenergetics by bringing a cellular and molecular resolution. Praised or disputed, the concept has never ceased to attract attention, leading to critical advances and unexpected insights. Here, we summarize recent experimental evidence further supporting the main tenets of the model. Thus, evidence for distinct metabolic phenotypes between neurons (mainly oxidative) and astrocytes (mainly glycolytic) have been provided by genomics and classical metabolic approaches. Moreover, it has become clear that astrocytes act as a syncytium to distribute energy substrates such as lactate to active neurones. Glycogen, the main energy reserve located in astrocytes, is used as a lactate source to sustain glutamatergic neurotransmission and synaptic plasticity. Lactate is also emerging as a neuroprotective agent as well as a key signal to regulate blood flow. Characterization of monocarboxylate transporter regulation indicates a possible involvement in synaptic plasticity and memory. Finally, several modeling studies captured the implications of such findings for many brain functions. The ANLS model now represents a useful, experimentally based framework to better understand the coupling between neuronal activity and energetics as it relates to neuronal plasticity, neurodegeneration, and functional brain imaging.
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Affiliation(s)
- Luc Pellerin
- Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Pierre J Magistretti
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, and Center for Psychiatric Neuroscience UNIL-CHUV, Lausanne, Switzerland
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35
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Bregestovski P, Bernard C. Excitatory GABA: How a Correct Observation May Turn Out to be an Experimental Artifact. Front Pharmacol 2012; 3:65. [PMID: 22529813 PMCID: PMC3329772 DOI: 10.3389/fphar.2012.00065] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 04/02/2012] [Indexed: 12/04/2022] Open
Abstract
The concept of the excitatory action of GABA during early development is based on data obtained mainly in brain slice recordings. However, in vivo measurements as well as observations made in intact hippocampal preparations indicate that GABA is in fact inhibitory in rodents at early neonatal stages. The apparent excitatory action of GABA seems to stem from cellular injury due to the slicing procedure, which leads to accumulation of intracellular Cl− in injured neurons. This procedural artifact was shown to be attenuated through various manipulations such as addition of energy substrates more relevant to the in vivo situation. These observations question the very concept of excitatory GABA in immature neuronal networks.
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Affiliation(s)
- Piotr Bregestovski
- INSERM URM 1106, Institut de Neuroscience des Systèmes, Aix-Marseille Université Marseille, France
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36
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Shetty PK, Galeffi F, Turner DA. Cellular Links between Neuronal Activity and Energy Homeostasis. Front Pharmacol 2012; 3:43. [PMID: 22470340 PMCID: PMC3308331 DOI: 10.3389/fphar.2012.00043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 02/24/2012] [Indexed: 12/20/2022] Open
Abstract
Neuronal activity, astrocytic responses to this activity, and energy homeostasis are linked together during baseline, conscious conditions, and short-term rapid activation (as occurs with sensory or motor function). Nervous system energy homeostasis also varies during long-term physiological conditions (i.e., development and aging) and with adaptation to pathological conditions, such as ischemia or low glucose. Neuronal activation requires increased metabolism (i.e., ATP generation) which leads initially to substrate depletion, induction of a variety of signals for enhanced astrocytic function, and increased local blood flow and substrate delivery. Energy generation (particularly in mitochondria) and use during ATP hydrolysis also lead to considerable heat generation. The local increases in blood flow noted following neuronal activation can both enhance local substrate delivery but also provides a heat sink to help cool the brain and removal of waste by-products. In this review we highlight the interactions between short-term neuronal activity and energy metabolism with an emphasis on signals and factors regulating astrocyte function and substrate supply.
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Affiliation(s)
- Pavan K Shetty
- Neurosurgery and Neurobiology, Research and Surgery Services, Durham VA Medical Center, Duke University Durham, NC, USA
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37
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Schurr A, Gozal E. Aerobic production and utilization of lactate satisfy increased energy demands upon neuronal activation in hippocampal slices and provide neuroprotection against oxidative stress. Front Pharmacol 2012; 2:96. [PMID: 22275901 PMCID: PMC3257848 DOI: 10.3389/fphar.2011.00096] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 12/23/2011] [Indexed: 12/21/2022] Open
Abstract
Ever since it was shown for the first time that lactate can support neuronal function in vitro as a sole oxidative energy substrate, investigators in the field of neuroenergetics have been debating the role, if any, of this glycolytic product in cerebral energy metabolism. Our experiments employed the rat hippocampal slice preparation with electrophysiological and biochemical methodologies. The data generated by these experiments (a) support the hypothesis that lactate, not pyruvate, is the end-product of cerebral aerobic glycolysis; (b) indicate that lactate plays a major and crucial role in affording neural tissue to respond adequately to glutamate excitation and to recover unscathed post-excitation; (c) suggest that neural tissue activation is accompanied by aerobic lactate and NADH production, the latter being produced when the former is converted to pyruvate by mitochondrial lactate dehydrogenase (mLDH); (d) imply that NADH can be utilized as an endogenous scavenger of reactive oxygen species (ROS) to provide neuroprotection against ROS-induced neuronal damage.
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Affiliation(s)
- Avital Schurr
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Louisville Louisville, KY, USA.
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38
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Kann O. The energy demand of fast neuronal network oscillations: insights from brain slice preparations. Front Pharmacol 2012; 2:90. [PMID: 22291647 PMCID: PMC3254178 DOI: 10.3389/fphar.2011.00090] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 12/20/2011] [Indexed: 01/09/2023] Open
Abstract
Fast neuronal network oscillations in the gamma range (30-100 Hz) in the cerebral cortex have been implicated in higher cognitive functions such as sensual perception, working memory, and, perhaps, consciousness. However, little is known about the energy demand of gamma oscillations. This is mainly caused by technical limitations that are associated with simultaneous recordings of neuronal activity and energy metabolism in small neuronal networks and at the level of mitochondria in vivo. Thus recent studies have focused on brain slice preparations to address the energy demand of gamma oscillations in vitro. Here, reports will be summarized and discussed that combined electrophysiological recordings, oxygen sensor microelectrodes, and live-cell fluorescence imaging in acutely prepared slices and organotypic slice cultures of the hippocampus from both, mouse and rat. These reports consistently show that gamma oscillations can be reliably induced in hippocampal slice preparations by different pharmacological tools. They suggest that gamma oscillations are associated with high energy demand, requiring both rapid adaptation of oxidative energy metabolism and sufficient supply with oxygen and nutrients. These findings might help to explain the exceptional vulnerability of higher cognitive functions during pathological processes of the brain, such as circulatory disturbances, genetic mitochondrial diseases, and neurodegeneration.
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Affiliation(s)
- Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg Heidelberg, Germany. oliver.kann@physiologie
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39
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Ivanov A, Zilberter Y. Critical state of energy metabolism in brain slices: the principal role of oxygen delivery and energy substrates in shaping neuronal activity. FRONTIERS IN NEUROENERGETICS 2011; 3:9. [PMID: 22232599 PMCID: PMC3247678 DOI: 10.3389/fnene.2011.00009] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Accepted: 12/10/2011] [Indexed: 12/22/2022]
Abstract
The interactive vasculo-neuro-glial system controlling energy supply in the brain is absent in vitro where energy provision is determined by experimental conditions. Despite the fact that neuronal activity is extremely energy demanding, little has been reported on the state of energy metabolism in submerged brain slices. Without this information, the arbitrarily chosen oxygenation and metabolic provisions make questionable the efficient oxidative metabolism in slices. We show that in mouse hippocampal slices (postnatal day 19–44), evoked neuronal discharges, spontaneous network activity (initiated by 4-aminopyridine), and synaptic stimulation-induced NAD(P)H autofluorescence depend strongly on the oxygen availability. Only the rate of perfusion as high as ~15 ml/min (95% O2) provided appropriate oxygenation of a slice. Lower oxygenation resulted in the decrease of both local field potentials and spontaneous network activity as well as in significant modulation of short-term synaptic plasticity. The reduced oxygen supply considerably inhibited the oxidation phase of NAD(P)H signaling indicating that the changes in neuronal activity were paralleled by the decrease in aerobic energy metabolism. Interestingly, the dependence of neuronal activity on oxygen tension was clearly shifted toward considerably larger pO2 values in slices when compared to in vivo conditions. With sufficient pO2 provided by a high perfusion rate, partial substitution of glucose in ACSF for β-hydroxybutyrate, pyruvate, or lactate enhanced both oxidative metabolism and synaptic function. This suggests that the high pO2 in brain slices is compulsory for maintaining oxidative metabolism, and glucose alone is not sufficient in fulfilling energy requirements during neuronal activity. Altogether, our results demonstrate that energy metabolism determines the functional state of neuronal network, highlighting the need for the adequate metabolic support to be insured in the in vitro experiments.
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Affiliation(s)
- Anton Ivanov
- INSERM UMR751, Université de la Méditerranée Marseille, France
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40
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Kasischke K. Lactate fuels the neonatal brain. FRONTIERS IN NEUROENERGETICS 2011; 3:4. [PMID: 21687795 PMCID: PMC3108381 DOI: 10.3389/fnene.2011.00004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 05/20/2011] [Indexed: 11/13/2022]
Affiliation(s)
- Karl Kasischke
- Department of Neurology, Center for Neural Development and Disease, University of Rochester Medical Center Rochester, NY, USA
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