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Kosenko E, Tikhonova L, Alilova G, Montoliu C. A Look into Liver Mitochondrial Dysfunction as a Hallmark in Progression of Brain Energy Crisis and Development of Neurologic Symptoms in Hepatic Encephalopathy. J Clin Med 2020; 9:E2259. [PMID: 32708652 PMCID: PMC7408643 DOI: 10.3390/jcm9072259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/18/2020] [Accepted: 07/13/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The relationship between liver disease and neuropathology in hepatic encephalopathy is well known, but the genesis of encephalopathy in liver failure is yet to be elucidated. Conceptually, the main cause of hepatic encephalopathy is the accumulation of brain ammonia due to impaired liver detoxification function or occurrence of portosystemic shunt. Yet, as well as taking up toxic ammonia, the liver also produces vital metabolites that ensure normal cerebral function. Given this, for insight into how perturbations in the metabolic capacity of the liver may be related to brain pathology, it is crucial to understand the extent of ammonia-related changes in the hepatic metabolism that provides respiratory fuel for the brain, a deficiency of which can give rise to encephalopathy. METHODS Hepatic encephalopathy was induced in starved rats by injection of ammonium acetate. Ammonia-induced toxicity was evaluated by plasma and freeze-clamped liver and brain energy metabolites, and mitochondrial, cytoplasmic, and microsomal gluconeogenic enzymes, including mitochondrial ketogenic enzymes. Parameters of oxidative phosphorylation were recorded polarographically with a Clark-type electrode, while other measures were determined with standard fluorometric enzymatic methods. RESULTS Progressive impairment of liver mitochondrial respiration in the initial stage of ammonia-induced hepatotoxicity and the subsequent energy crisis due to decreased ATP synthesis lead to cessation of gluconeogenesis and ketogenesis. Reduction in glucose and ketone body supply to the brain is a terminal event in liver toxicity, preceding the development of coma. CONCLUSIONS Our study provides a framework to further explore the relationship between hepatic dysfunction and progression of brain energy crisis in hepatic encephalopathy.
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Affiliation(s)
- Elena Kosenko
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia; (L.T.); (G.A.)
| | - Lyudmila Tikhonova
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia; (L.T.); (G.A.)
| | - Gubidat Alilova
- Institute of Theoretical and Experimental Biophysics of Russian Academy of Sciences, 142290 Pushchino, Russia; (L.T.); (G.A.)
| | - Carmina Montoliu
- Hospital Clinico Research Foundation, INCLIVA Health Research Institute, 46010 Valencia, Spain;
- Pathology Department, Faculty of Medicine, University of Valencia, 46010 Valencia, Spain
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Kosenko EA, Tikhonova LA, Alilova GA, Montoliu C, Barreto GE, Aliev G, Kaminsky YG. Portacaval shunting causes differential mitochondrial superoxide production in brain regions. Free Radic Biol Med 2017; 113:109-118. [PMID: 28964916 DOI: 10.1016/j.freeradbiomed.2017.09.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/08/2017] [Accepted: 09/25/2017] [Indexed: 01/23/2023]
Abstract
The portacaval shunting (PCS) prevents portal hypertension and recurrent bleeding of esophageal varices. On the other hand, it can induce chronic hyperammonemia and is considered to be the best model of mild hepatic encephalopathy (HE). Pathogenic mechanisms of HE and dysfunction of the brain in hyperammonemia are not fully elucidated, but it was originally suggested that the pathogenetic defect causes destruction of antioxidant defense which leads to an increase in the production of reactive oxygen species (ROS) and the occurrence of oxidative stress. In order to gain insight into the pathogenic mechanisms of HE in the brain tissue, we investigated the effects of PCS in rats on free radicals production and activity levels of antioxidant and prooxidant enzymes in mitochondria isolated from different brain areas. We found that O2·- production, activities of Mn-superoxide dismutase (Mn-SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione transferase (GT), nitric oxide synthase (NOS), and levels of carbonylated proteins differed between the four brain regions both in the amount and response to PCS. In PCS rats, Mn-SOD activity in the cerebellum was significantly decreased, and remained unchanged in the neocortex, hippocampus and striatum compared with that in sham-operated animals. Among the four brain regions in control rats, the levels of the carbonyl groups in mitochondrial proteins were maximal in the cerebellum. 4 weeks after PCS, the content of carbonylated proteins were higher only in mitochondria of this brain region. Under control conditions, O2·- production by submitochondrial particles in the cerebellum was significantly higher than in other brain regions, but was significantly increased in each brain region from PCS animals. Indeed, the production of O2·- by submitochondrial particles correlated with mitochondrial ammonia levels in the four brain regions of control and PCS-animals. These findings are the first to suggest that in vivo levels of ammonia in the brain directly affect the rate of mitochondrial O2·- production.
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Affiliation(s)
- Elena A Kosenko
- Institute of Theoretical and Experimental Biophysics, Pushchino, Russia.
| | | | - Gubidat A Alilova
- Institute of Theoretical and Experimental Biophysics, Pushchino, Russia
| | - Carmina Montoliu
- Fundación Investigación Hospital Clínico, Instituto Investigación Sanitaria-INCLIVA, Valencia, Spain
| | - George E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile
| | - Gjumrakch Aliev
- GALLY International Biomedical Research Institute Inc., 7733 Louis Pasteur Drive, #330, San Antonio, TX 78229, USA; School of Health Science and Healthcare Administration, University of Atlanta, E. Johns Crossing, #175, Johns Creek, GA 30097, USA.
| | - Yury G Kaminsky
- Institute of Theoretical and Experimental Biophysics, Pushchino, Russia
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Hangzo H, Banerjee B, Saha S, Saha N. Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia. FISH PHYSIOLOGY AND BIOCHEMISTRY 2017; 43:77-88. [PMID: 27492114 DOI: 10.1007/s10695-016-0269-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH4Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H2O2) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.
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Affiliation(s)
- Hnunlalliani Hangzo
- Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, 793022, India
| | - Bodhisattwa Banerjee
- Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, 793022, India
| | - Shrabani Saha
- Institute of Biotechnology, Amity University, Sector 125, Noida, 201303, India
| | - Nirmalendu Saha
- Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, 793022, India.
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Kosenko EA, Tikhonova LA, Kaminsky YG. Ammonia and enzymes of ammonia metabolism in different brain regions in hyperammonemia. NEUROCHEM J+ 2015. [DOI: 10.1134/s1819712415020087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yu N, Wang S, Wang P, Li Y, Li S, Wang L, Chen H, Wang Y. The calcium uniporter regulates the permeability transition pore in isolated cortical mitochondria. Neural Regen Res 2015; 7:109-13. [PMID: 25767484 PMCID: PMC4354124 DOI: 10.3969/j.issn.1673-5374.2012.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 12/20/2011] [Indexed: 01/28/2023] Open
Abstract
To investigate the influence of the mitochondrial calcium uniporter on the mitochondrial permeability transition pore, the present study observed mitochondrial morphology in cortical neurons isolated from adult rats using transmission electron microscopy, and confirmed the morphology and activity of isolated mitochondria by detecting succinic dehydrogenase and monoamine oxidase, two mitochondrial enzymes. Isolated mitochondria were treated with either ruthenium red, an inhibitor of the uniporter, spermine, an activator of the uniporter, or in combination with cyclosporin A, an inhibitor of the mitochondrial permeability transition pore. Results showed that ruthenium red inhibited CaCl2-induced mitochondrial permeability transition pore opening, spermine enhanced opening, and cyclosporin A attenuated the effects of spermine. Results demonstrated that the mitochondrial calcium uniporter plays a role in regulating the mitochondrial permeability transition pore in mitochondria isolated from the rat brain cortex.
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Affiliation(s)
- Ning Yu
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Shilei Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Peng Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Yu Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Shuhong Li
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Li Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Hongbing Chen
- Cerebrovascular Disease Institute, Qingdao University Medical College, Qingdao 266003, Shandong Province, China
| | - Yanting Wang
- Department of Anesthesiology, Affiliated Hospital of Qingdao University Medical College, Qingdao 266003, Shandong Province, China
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Kaminsky YG, Beloushko EE, Kosenko EA. Antioxidant defense in the rat brain cortex, cerebellum, hippocampus, and striatum and its alterations during portacaval shunting. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414030064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Kaminsky YG, Kosenko EA. Homeostasis of mitochondrial calcium is disturbed in the cerebellum but not in other brain areas during chronic hyperammonemia. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414020056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Shen F, Wu LP, Lu Y, Liang HW, Bruce I, Xia Q. Mitochondrial permeability transition dynamics: an indicator of mitochondrial potassium channel opener. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2012; 2005:7317-20. [PMID: 17281970 DOI: 10.1109/iembs.2005.1616201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mitochondrial permeability transition (MPT) is an intracellular event that is closely related to apoptosis and necrosis. However, whether this process underlies the recently reported neuroprotective potency of mitochondrial potassium channel openers applied in vivo remains uncertain. This study aims to clarify this issue by determining the effects of potassium channel openers on MPT dynamics in vitro along with their in vivo effects. Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 90 min, followed by reperfusion. 30μl of diazoxide, an opener of the mitochondrial adenosine triphosphate-sensitive K<sup>+</sup>channel (mitoK<inf>ATP</inf>), or NS1619, an opener of the mitochondrial Ca<sup>2+</sup>-activated potassium channel (mitoK<inf>Ca</inf>) (2 mM and 0.1 mM respectively), was infused into the right lateral cerebral ventricle 15 min before the induction of ischemia. Neurological scores were assessed 24 h after MCAO and then infarct area was determined by standard 2,3,5-triphenyltetrazolium chloride staining techniques. To further clarify the capacity of diazoxide and NS1619 to protect mitochondria from Ca<sup>2+</sup>-induced MPT, we isolated brain-derived non-synaptosomal mitochondria and evaluated the effects of diazoxide and NS1619 on Ca<sup>2+</sup>-induced MPT dynamics through measurement of spectrophotometric alterations in light scattering at 520 nm. Neurological scores and infarct size were improved in animals pretreated with diazoxide and NS1619. In isolated mitochondria, MPT was readily induced by 200 μM Ca<sup>2+</sup>and was effectively inhibited by diazoxide and NS1619. The specific MPT pore opener atractyloside abolished the inhibitory effects. According to time-constant analysis, MPT dynamics was in accordance with the neuroprotective effects of channel openers in vivo.
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Affiliation(s)
- Fang Shen
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China. (phone: 86-571-87217146; fax: 86-571-87217147; e-mail: )
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Kosenko E, Poghosyan A, Kaminsky Y. Subcellular compartmentalization of proteolytic enzymes in brain regions and the effects of chronic β-amyloid treatment. Brain Res 2011; 1369:184-93. [DOI: 10.1016/j.brainres.2010.10.078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 10/19/2010] [Accepted: 10/20/2010] [Indexed: 12/14/2022]
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Lin GH, Lin L, Liang HW, Ma X, Wang JY, Wu LP, Jiang HD, Bruce IC, Xia Q. Antioxidant Action of a Chrysanthemum morifolium Extract Protects Rat Brain Against Ischemia and Reperfusion Injury. J Med Food 2010; 13:306-11. [DOI: 10.1089/jmf.2009.1184] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Guo-Hua Lin
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Lin Lin
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Hua-Wei Liang
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Xin Ma
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Jing-Ye Wang
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Li-Ping Wu
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Hui-Di Jiang
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Iain C. Bruce
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
| | - Qiang Xia
- Department of Physiology, Zhejiang University School of Medicine, Zhejiang University, Hangzhou, China
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Abstract
AbstractMitochondrial enzyme monoamine oxidase A (MAO-A) generates hydrogen peroxide (H2O2) and is up-regulated by Ca2+ and presumably by ammonia. We hypothesized that MAO-A may be under the control of NMDA receptors in hyperammonemia. In this work, the in vivo effects of single dosing with ammonia and NMDA receptor antagonist MK-801 and the in vitro effect of Ca2+ on MAO-A activity in isolated rat brain mitochondria were studied employing enzymatic procedure. Intraperitoneal injection of rats with ammonia led to an increase in MAO-A activity in mitochondria indicating excessive H2O2 generation. Calcium added to isolated mitochondria stimulated MAO-A activity by as much as 84%. MK-801 prevented the in vivo effect of ammonia, implying that MAO-A activation in hyperammonemia is mediated by NMDA receptors. These data support the conclusion that brain mitochondrial MAO-A is regulated by the function of NMDA receptors. The enzyme can contribute to the oxidative stress associated with hyperammonemic conditions such as encephalopathy and Alzheimer’s disease. The attenuation of the oxidative stress highlights MAO-A inactivation and NMDA receptor antagonists as sources of novel avenues in the treatment of mental disorders.
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Kaminsky YG, Kosenko EA. Effects of amyloid-beta peptides on hydrogen peroxide-metabolizing enzymes in rat brainin vivo. Free Radic Res 2009; 42:564-73. [DOI: 10.1080/10715760802159057] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Kosenko E, Kaminsky Y, Solomadin I, Marov N, Venediktova N, Felipo V, Montoliu C. Acute ammonia neurotoxicity in vivo involves increase in cytoplasmic protein P53 without alterations in other markers of apoptosis. J Neurosci Res 2007; 85:2491-9. [PMID: 17551980 DOI: 10.1002/jnr.21385] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Acute intoxication with large ammonia doses leads to activation of NMDA receptors in the brain, resulting in oxidative stress and disturbance of mitochondrial function. Altered mitochondrial function is a crucial step in some mechanisms of cellular apoptosis. This study assesses whether ammonia intoxication in vivo leads to induction of apoptotic markers such as permeability transition pore (PTP) formation, caspase-3, and caspase-9 activation, changes in p53 protein, or cytochrome c release. Acute ammonia intoxication did not affect caspase-9 or caspase-3 activities. The mitochondrial membrane potential also remained unaltered in non-synaptic brain mitochondria after injection of ammonia, indicating that ammonia did not induce PTP formation in brain in vivo. The nuclear level of p53 did not change, whereas its cytoplasmic level increased approximately two-fold. In agreement with the theory that translocation of the p53 from cytosol to nuclei is an essential step for induction of apoptosis we did not find apoptotic nuclei in brain of rats injected with ammonia. This supports the idea that ammonia neurotoxicity does not involve apoptosis and points to impaired p53 transfer from cytoplasm to nuclei as a possible preventer of apoptosis. We did not find any release of cytochrome c from mitochondria to cytosol after ammonia injection. Cytochrome c content was significantly reduced (30%) in brain mitochondria from rats injected with ammonia. This decrease may contribute to the reduced state 3 respiration, decreased respiratory control index, and disturbances in the mitochondrial electron transport chain in brain mitochondria from rats injected with ammonia.
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Affiliation(s)
- Elena Kosenko
- Institute of Theoretical & Experimental Biophysics, RAS, Pushchino, Russia
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Kaminsky YG, Kosenko EA, Venediktova NI, Felipo V, Montoliu C. Apoptotic markers in the mitochondria, cytosol, and nuclei of brain cells during ammonia toxicity. NEUROCHEM J+ 2007. [DOI: 10.1134/s1819712407010114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Wu LP, Shen F, Lu Y, Bruce I, Xia Q. Differing effects of cyclosporin a on swelling amplitude and time constant of mitochondria from normal and ischemic rat brain. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:4317-20. [PMID: 17281190 DOI: 10.1109/iembs.2005.1615420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The purpose of this study was to investigate the effect of cyclosporin A on swelling amplitude and time constant of mitochondria isolated from normal and ischemic rat brain and to observe the possible role of the mitochondrial ATP-sensitive potassium channel on mitochondrial permeability transition. Mitochondrial swelling was evaluated by spectrophotometry. Cyclosporin A at 0.5 or 1 microM and diazoxide at 30 microM significantly decreased the swelling amplitude and attenuated the reduction of time constant of mitochondria isolated from normal brain mitochondria induced by 200 microM calcium, an effect abolished by atractyloside at 100 microM. However, cyclosporin A at 5 microM did not affect mitochondrial swelling. In mitochondria from ischemic brain, cyclosporin A at 0.5 microM but not 1 microM significantly decreased mitochondrial swelling amplitude and attenuated the reduction of time constant, which was abolished by atractyloside. Diazoxide had an effect similar to cyclosporin A at 0.5 microM, which was blocked by atractyloside or 5-hydroxydecanoate at 100 microM and 200 microM. Compared with mitochondria isolated from normal brain, those from ischemic brain were more sensitive to cyclosporin A. Activation of the mitochondrial ATP-sensitive potassium channel may be one of the mechanisms by which opening of the mitochondrial permeability transition pore is inhibited.
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Affiliation(s)
- Li-Ping Wu
- Department of Physiology, Zhejiang University School of Medicine, Hangzhou, China. (phone: 0086-571-87217146; fax: 0086-571-87217147)
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Kosenko E, Venediktova N, Kaminsky Y, Montoliu C, Felipo V. Sources of oxygen radicals in brain in acute ammonia intoxication in vivo. Brain Res 2003; 981:193-200. [PMID: 12885441 DOI: 10.1016/s0006-8993(03)03035-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The effects of acute ammonia intoxication on reactive oxygen species production by different sources in rat brain were studied. Ammonia intoxication in vivo leads to reduced activity of superoxide dismutase (SOD), catalase and glutathione peroxidase in brain nonsynaptic mitochondria and increased formation of O(2)(-) by submitochondrial particles. It also results in increased xanthine oxidase (XO) activity and decreased xanthine dehydrogenase (XDH)/XO activity ratio indicating conversion of XDH to XO and also increases monoamine oxidase A (MAO-A) activity but not of MAO-B. Blocking NMDA receptors with MK-801 prevents ammonia-induced oxidative stress, XDH to XO conversion and MAO-A activation. Ammonia intoxication did not lead to H(2)O(2) formation by mitochondria, in spite of increased O(2)(-) generation. The main source of H(2)O(2) in the mitochondrial matrix was Mn-SOD. Ammonia intoxication in vivo leads to increased superoxide and decreased hydrogen peroxide in nonsynaptic brain mitochondria. Increased superoxide is due to increased formation by the respiratory chain and by xanthine and aldehyde oxidases and decreased elimination by antioxidant enzymes. The reduced formation of hydrogen peroxide is due to the reduced activity of Mn-SOD. Prevention of ammonia-induced production of reactive oxygen species by MK-801 supports the idea that it is mediated by activation of NMDA receptors.
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Affiliation(s)
- Elena Kosenko
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, 142290 Russia
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