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El Khiat A, El Hiba O, Tamegart L, Rais H, Fdil N, Sellami S, El Mokhtar MA, Gamrani H. Time dependent alteration of locomotor behavior in rat with acute liver failure induced cerebellar neuroinflammation and neuro-astroglial damage. J Chem Neuroanat 2021; 119:102055. [PMID: 34863855 DOI: 10.1016/j.jchemneu.2021.102055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/27/2021] [Accepted: 11/27/2021] [Indexed: 11/26/2022]
Abstract
Hepatic encephalopathy (HE) is a neurophysiological syndrome secondary to acute or chronic liver failure. Studies showed that HE patients exhibit a deficit in motor coordination, which may result from cerebellar functional impairment. The aim of this study is to assess the time-dependent alteration of locomotor behavior and the glial and neuronal alteration in rat with acute HE induced chemically. The study was carried out in male Sprague-Dawley rats with thioacetamide (TAA) induced acute liver failure at different stages 12 h, 24 h and 36 h. Hepatic and renal functions were assessed via various biochemical and histopathological examinations, while the cerebellum and the midbrain were examined using histology and immunohistochemistry for tyrosine hydroxylase (TH), cyclooxygenase-2 (COX-2) and glial fibrillary acidic protein (GFAP). We used as well, the open field test and the Rotarod test for assessing the locomotor activity and coordination. Our data showed a progressive loss of liver function and a progressive alteration in locomotor behavior and motor coordination in acute HE rats. In the cerebellum, we noted an increase in the degeneration of cerebellar Purkinje neurons parallel to increased COX-2 immunoreactivity together with astrocytic morphology and density changes. Likewise, in substantia nigra pars compacta, TH levels were reduced. We showed through the current study, a progressive deterioration in locomotor behavior in acute HE rats, as a result of Purkinje neurons death and a deficient dopaminergic neurotransmission, together with the morpho-functional astroglial modifications involving the oxidative stress and neuroinflammation.
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Affiliation(s)
- Abdelaati El Khiat
- Laboratory of Clinical and Experimental Neurosciences and Environment, faculty of Medicine and Pharmacy, Cadi Ayyad University, 4000 Marrakech, Morocco; Higher Institute of Nursing Professions and Health Techniques, Ouarzazate, Morocco.
| | - Omar El Hiba
- Nutritional Physiopathologies and Toxicology Team, faculty of Sciences, Chouaib Doukkali University, El Jadida, Morocco.
| | - Lahcen Tamegart
- Laboratory of Clinical and Experimental Neurosciences and Environment, faculty of Medicine and Pharmacy, Cadi Ayyad University, 4000 Marrakech, Morocco; Department of Biology, Faculty of Science, Abdelmalek Essaadi University, Tetouan, Morocco
| | - Hanane Rais
- Laboratory of Morphosciences, Faculty of Medicine and Pharmacy, Cadi Ayyad University, Morocco; Mohammed VI University Hospital, Marrakech, Morocco
| | - Naima Fdil
- Metabolics platform, Biochemistry Laboratory, Faculty of Medicine, Cadi Ayyad University, Sidi Abbad, BP 40000 Marrakech, Morocco
| | | | - Mohamed Ait El Mokhtar
- Laboratory of Biochemistry, Environment &Agri-food URAC 36, Department of Biology, Faculty of Sciences and Techniques, Mohmmedia, Hassan II University of Casablanca, Morocco
| | - Halima Gamrani
- Laboratory of Clinical and Experimental Neurosciences and Environment, faculty of Medicine and Pharmacy, Cadi Ayyad University, 4000 Marrakech, Morocco.
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Dhanda S, Sandhir R. Role of dopaminergic and serotonergic neurotransmitters in behavioral alterations observed in rodent model of hepatic encephalopathy. Behav Brain Res 2015; 286:222-35. [PMID: 25639545 DOI: 10.1016/j.bbr.2015.01.042] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/17/2015] [Accepted: 01/22/2015] [Indexed: 02/06/2023]
Abstract
The present study was designed to evaluate the role of biogenic amines in behavioral alterations observed in rat model of hepatic encephalopathy (HE) following bile duct ligation (BDL). Male Wistar rats subjected to BDL developed biliary fibrosis after four weeks which was supported by altered liver function tests, increased ammonia levels and histological staining (Sirius red). Animals were assessed for their behavioral performance in terms of cognitive, anxiety and motor functions. The levels of dopamine (DA), serotonin (5-HT), epinephrine and norepinephrine (NE) were estimated in different regions of brain viz. cortex, hippocampus, striatum and cerebellum using HPLC along with activity of monoamine oxidase (MAO). Cognitive assessment of BDL rats revealed a progressive decline in learning, memory formation, retrieval, exploration of novel environment and spontaneous locomotor activity along with decrease in 5-HT and NE levels. This was accompanied by an increase in MAO activity. Motor functions of BDL rats were also altered which were evident from decrease in the time spent on the rotating rod and higher foot faults assessed using narrow beam walk task. A global decrease was observed in the DA content along with an increase in MAO activity. Histopathological studies using hematoxylin-eosin (H&E) and cresyl violet exhibited marked neuronal degeneration, wherein neurons appeared more pyknotic, condensed and damaged. The results reveal that dopaminergic and serotonergic pathways are disturbed in chronic liver failure post-BDL which may be responsible for behavioral impairments observed in HE.
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Affiliation(s)
- Saurabh Dhanda
- Department of Biochemistry, Basic Medical Science Block, Panjab University, Chandigarh 160014, India
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science Block, Panjab University, Chandigarh 160014, India.
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Differential mechanisms of opioidergic and dopaminergic systems of the ventral hippocampus (CA3) in anxiolytic-like behaviors induced by cholestasis in mice. Eur J Pharmacol 2013; 714:352-8. [DOI: 10.1016/j.ejphar.2013.07.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 07/09/2013] [Accepted: 07/16/2013] [Indexed: 11/20/2022]
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El Hiba O, Gamrani H, Chatoui H, Ahboucha S. Loss of tyrosine hydroxylase expression within the nigro-striato-cortical pathways in the cirrhotic rat: the possible restorative effect of the neurosteroid dehydroepiandrosterone sulfate. Acta Histochem 2013; 115:637-45. [PMID: 23453752 DOI: 10.1016/j.acthis.2013.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/21/2013] [Accepted: 01/23/2013] [Indexed: 12/25/2022]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric disorder occurring as a consequence of both acute and chronic liver failure. Advanced HE is generally accompanied with extrapyramidal symptoms including rigidity and tremor, which may reflect alterations of the dopaminergic system. Recently we reported a beneficial effect of the neuroactive steroid dehydroepiandrosterone sulfate (DHEAS) in cirrhotic rats, however the mechanisms of such an effect by DHEAS were not addressed. In the present study, we describe the changes of the dopaminergic system occurring in the cirrhotic rats and concomitantly we investigated the effect of DHEAS on this system in Sprague-Dawley rats using the expression of tyrosine hydroxylase (TH) as a neuronal marker. Rats were submitted to bile duct ligation (BDL) surgery and TH immunohistochemistry was assessed in the Substantia nigra pars compacta (SNc), striatum, ventral tegmental area (VTA) and the cortex. TH immunoreactivity showed a significant diminution in both SNc and VTA concomitantly with the cortical and the striatal outputs in the BDL rats vs. controls. Three daily injections of 5mg/kg of DHEAS to BDL rats significantly normalized TH expression decrease in both SNc and VTA as well as dopaminergic projections to the striatum and the cortex of BDL rats. The present data support an involvement of the dopaminergic system in mild HE and a possible beneficial effect of the neurosteroid DHEAS as a potential pharmacological treatment of mild HE.
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Affiliation(s)
- Omar El Hiba
- Neurosciences, Pharmacology and Environment Unit, Faculty of Sciences Semlalia, Cadi University Ayyad, Marrakesh, Morocco
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Nasehi M, Amin Yavari S, Zarrindast MR. Synergistic effects between CA1 mu opioid and dopamine D1-like receptors in impaired passive avoidance performance induced by hepatic encephalopathy in mice. Psychopharmacology (Berl) 2013; 227:553-66. [PMID: 23404062 DOI: 10.1007/s00213-013-2987-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 01/14/2013] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND AIM Numerous investigations have indicated that hepatic encephalopathy (HE) alters the levels of various neurotransmitters. However, comprehensive data regarding the effects of CA1 opioidergic and dopaminergic (DAergic) systems on HE-induced amnesia are still lacking. METHODS Following intra-dorsal hippocampal (CA1) injection of mu opioid and dopamine D1- and D2-like receptors antagonists in male mice, one-trial step-down and hole-board paradigms were used to assess memory and exploratory behaviors, respectively. RESULTS Our data demonstrated that HE impairs memory 24 days after bile duct ligation (BDL). Furthermore, while the higher dose of DA D1-like receptor antagonist (SCH23390, 0.5 μg/mouse) induced amnesia and anxiogenic-like behaviors, mu receptor antagonist (naloxone: 0.0125, 0.025 and 0.05 μg/mouse) and DA D2-like receptor antagonist (sulpiride: 0.0625, 0.125 and 0.25 μg/mouse) by themselves, could not exert an effect on memory performance in passive avoidance task. On the other hand, pre-test injection of all drugs reversed the HE-induced amnesia 24 days after BDL, while having no effect on exploratory behaviors. Pre-test co-administration of the subthreshold dose SCH23390 (0.25 μg/mouse) and sulpiride (0.0625 μg/mouse) or naloxone (0.0125 μg/mouse) could likewise reverse the BDL-induced amnesia. However, when the subthreshold sulpiride plus naloxone were co-administered, BDL-induced amnesia was not blocked. CONCLUSIONS Memory performance is impaired 24 days post BDL and CA1 mu opioid and DA D1-like receptors antagonist synergistic effects are likely involved in this phenomenon.
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MESH Headings
- Animals
- Avoidance Learning/drug effects
- Avoidance Learning/physiology
- CA1 Region, Hippocampal/drug effects
- CA1 Region, Hippocampal/metabolism
- CA1 Region, Hippocampal/physiopathology
- Disease Models, Animal
- Dopamine Antagonists/administration & dosage
- Dopamine Antagonists/pharmacology
- Drug Synergism
- Exploratory Behavior/drug effects
- Exploratory Behavior/physiology
- Hepatic Encephalopathy/metabolism
- Hepatic Encephalopathy/physiopathology
- Hepatic Encephalopathy/psychology
- Male
- Memory/drug effects
- Memory/physiology
- Memory Disorders/metabolism
- Memory Disorders/physiopathology
- Memory Disorders/psychology
- Mice
- Mice, Inbred Strains
- Narcotic Antagonists/administration & dosage
- Narcotic Antagonists/pharmacology
- Receptors, Dopamine D1/antagonists & inhibitors
- Receptors, Dopamine D1/metabolism
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/metabolism
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Affiliation(s)
- Mohammad Nasehi
- Department of Biology, Faculty of Basic Sciences, Islamic Azad University, Garmsar branch, Semnan, Iran
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Effects of dopamine receptor agonist and antagonists on cholestasis-induced anxiolytic-like behaviors in rats. Eur J Pharmacol 2013; 702:25-31. [DOI: 10.1016/j.ejphar.2013.01.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 12/20/2012] [Accepted: 01/15/2013] [Indexed: 01/08/2023]
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Liver. CANINE AND FELINE GASTROENTEROLOGY 2013. [PMCID: PMC7161409 DOI: 10.1016/b978-1-4160-3661-6.00061-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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8
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Chepkova AN, Selbach O, Haas HL, Sergeeva OA. Ammonia-induced deficit in corticostriatal long-term depression and its amelioration by zaprinast. J Neurochem 2012; 122:545-56. [PMID: 22639911 DOI: 10.1111/j.1471-4159.2012.07806.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hyperammonemia is a major pathophysiological factor in encephalopathies associated with acute and chronic liver failure. On mouse brain slice preparations, we analyzed the effects of ammonia on the characteristics of corticostriatal long-term depression (LTD) induced by electrical stimulation of cortical input or pharmacological activation of metabotropic glutamate receptors. Long exposure of neostriatal slices to ammonium chloride impaired the induction and/or expression of all studied forms of LTD. This impairment was reversed by the phosphodiesterase inhibitor zaprinast implying lowered cGMP signaling in LTD suppression. Polyphenols from green tea rescued short-term corticostriatal plasticity, but failed to prevent the ammonia-induced deficit of LTD. Zaprinast counteracts the ammonia-induced impairment of long-term corticostriatal plasticity and may thus improve fine motor skills and procedural learning in hepatic encephalopathy.
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Affiliation(s)
- Aisa N Chepkova
- Department of Neurophysiology, Medical Faculty, Heinrich-Heine-University, Dusseldorf, Germany
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9
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Takeda T, Vacanti JP. Hepatocyte transplantation in the dalmatian dog model of hyperuricosuria. ACTA ACUST UNITED AC 2011; 1:355-60. [PMID: 19877899 DOI: 10.1089/ten.1995.1.355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Hepatocyte transplantation shows promise as a therapy to support liver function. We have previously shown that hepatocytes can be transplanted into prevascularized synthetic polymers in rat and pig models. This study was designed to assess the possibility of correction of a liver metabolic defect in a dog model. The Dalmatian dog is known to have an inborn error of metabolism in the hepatocyte that causes a decrease in the degradation of uric acid into allantoin. This leads to a rise in uric acid levels in blood and urine. Four male Dalmatian dogs 18-28 kg in weight were studied as recipients of normal hepatocytes. Poly vinyl alcohol sponges measuring 250 cm(2) x 5 mm were first implanted between the leaves of the mesentery and the omentum to form prevascularized implantation beds, and an end-to-side portacaval shunt to induce hepatotrophic stimulation was made. After 7 days 1.5 x 10(10) normal hepatocytes obtained from donor beagles receiving cyclosporine immunosuppression were implanted into the prevascularized sponges. Excretion of uric acid in urine decreased from 136.3 +/- 18.1 to 44.1 +/- 20.4 micromol/kg/day (p < 0.05) in these animals at 2 weeks, and continued for 6 weeks. Uric acid levels in serum did not change significantly from 26.77 +/- 10.30 to 39.65 +/- 9.09 micromol/liter (mean +/- SD) 4 weeks after transplantation. Control Dalmatians, which were transplanted with Dalmatian hepatocytes, remained at baseline. Creatinine clearance was unchanged. We conclude that hepatocyte transplantation is possible in this Dalmatian dog model of hyperuricosuria and that urinary excretion of uric acid can be decreased by beagle hepatocyte transplantation delivered in prevascularized synthetic polymer sponges using portacaval shunts as hepatotrophic stimulation.
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Affiliation(s)
- T Takeda
- Department of Surgery, Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115
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10
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Amodio P, Pellegrini A, Ubiali E, Mathy I, Piccolo FD, Orsato R, Gatta A, Guerit JM. The EEG assessment of low-grade hepatic encephalopathy: Comparison of an artificial neural network-expert system (ANNES) based evaluation with visual EEG readings and EEG spectral analysis. Clin Neurophysiol 2006; 117:2243-51. [PMID: 16931145 DOI: 10.1016/j.clinph.2006.06.714] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 06/21/2006] [Accepted: 06/28/2006] [Indexed: 01/28/2023]
Abstract
OBJECTIVE The EEG provides an objective staging of hepatic encephalopathy (HE), but its interpretation may be biased by inter-observer variability. This study aims at comparing an entirely automatic EEG classification of HE based on an artificial neural network-expert system procedure (ANNES) with visual and spectral analysis based EEG classifications. METHODS Two hundred and thirty-eight consecutive cirrhotic patients underwent closed-eye EEG. They were followed up for up to one-year to detect bouts of overt HE and death. The EEG was classified by ANNES, qualitative visual reading, main basic rhythm frequency and spectral analysis. The classifications were assessed on the basis of: (i) match with liver function, (ii) prognostic value and (iii) repeatability. RESULTS All classifications were found to be related to the severity of liver failure, with cognitive findings and a history of previous bouts of HE. All of them had prognostic value on the occurrence of overt HE and on survival. The ANNES based classification was more repeatable than the qualitative visual one, and had the advantage of detecting low power EEG, but its efficiency in analyzing low-grade alterations was questionable. CONCLUSIONS An entirely automatic - ANNES based - EEG classification of HE can improve the repeatability of EEG assessment, but further improvement of the device is required to classify mild alterations. SIGNIFICANCE The ANNES based EEG grading of HE needs further improvements to be recommended in clinical practice, but it is already sufficient for detecting normal and clearly altered EEG tracings.
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Affiliation(s)
- P Amodio
- Department of Clinical and Experimental Medicine, University of Padova, Padova, Italy.
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Zeneroli ML, Avallone R, Corsi L, Venturini I, Baraldi C, Baraldi M. Management of hepatic encephalopathy: role of rifaximin. Chemotherapy 2005; 51 Suppl 1:90-5. [PMID: 15855752 DOI: 10.1159/000081994] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric syndrome, which develops in patients with acute or chronic liver failure. It is widely accepted to be due to impairment of hepatic clearance of toxic products from the gut such as ammonia. Accumulation of ammonia induces a glutamate neurotoxicity leading to an increased tone of the gamma-aminobutyric acid A (GABA-A) receptor system in the brain which results in HE. Factors either increasing the ammonia levels (protein load, constipation, sepsis, or gastrointestinal bleeding) or potentiating the functional activity of the GABAergic system [natural benzodiazepine-like compounds (NBZDs) or exogenous benzodiazepines] may act as precipitating factors of HE. NBZDs are present in trace amounts in the blood of normal subjects and have been found to be increased in the blood of patients with liver cirrhosis, with or without HE. These compounds may derive either from the diet since they have been found in plants, vegetables and animals or from gut bacteria. The observation that intestinal bacterial flora is involved in the production of both primary agent of HE (ammonia) and precipitating factors (NBZDs) suggests that the use of nonabsorbable antibiotics such as rifaximin may be useful in preventing episodes of HE in patients with liver cirrhosis.
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Affiliation(s)
- Maria Luisa Zeneroli
- Department of Medicine and Medical Specialities, University of Modena and Reggio Emilia, Modena, Italy.
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12
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Albrecht J, Zielińska M. The role of inhibitory amino acidergic neurotransmission in hepatic encephalopathy: a critical overview. Metab Brain Dis 2002; 17:283-94. [PMID: 12602505 DOI: 10.1023/a:1021901700493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Gamma-Aminobutyric acid (GABA) is the main inhibitory amino acid in the central nervous system (CNS). Experiments with animal models of HE, and with brain slices or cultured CNS cells treated with ammonia, have documented changes in GABA distribution and transport, and modulation of the responses of both the GABA(A)-benzodiazepine receptor complex and GABA(B) receptors. Although many of the data point to an enhancement of GABAergic transmission probably contributing to HE, the evidence is not unequivocal. The major weaknesses of the GABA theory are (1) in a vast majority of HE models, there were no alterations of GABA content in the brain tissue and/or extracellular space, indicating that exposure of neurons to GABA may not have been altered, (2) changes in the affinity and capacity of GABA receptor binding were either absent or qualitatively different in HE models of comparable severity and duration, and (3) no sound changes in the GABAergic system parameters were noted in clinical cases of HE. Taurine (Tau) is an amino acid that is thought to mimic GABA function because of its agonistic properties towards GABA(A) receptors, and to contribute to neuroprotection and osmoregulation. These effects require Tau redistribution between the different cell compartments and the extracellular space. Acute treatment with ammonia evokes massive release of radiolabeled or endogenous Tau from CNS tissues in vivo and in vitro, and the underlying mechanism of Tau release differs from the release evoked by depolarizing conditions or hypoosmotic treatment. Subacute or chronic HE, and also long-term treatment of cultured CNS cells in vitro with ammonia, increase spontaneous Tau "leakage" from the tissue. This is accompanied by a decreased potassium- or hypoosmolarity-induced release of Tau and often by cell swelling, indicating impaired osmoregulation. In in vivo models of HE, Tau leakage is manifested by its increased accumulation in the extrasynaptic space, which may promote inhibitory neurotransmission and/or cell membrane protection. In chronic HE in humans, decreased Tau content in CNS is thought to be one of the causes of cerebral edema. However, understanding of the impact of the changes in Tau content and transport on the pathogenic mechanisms of HE is hampered by the lack of clear-cut evidence regarding the various roles of Tau in the normal CNS.
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Affiliation(s)
- Jan Albrecht
- Department of Neurotoxicology, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
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Waśkiewicz J, Freśko I, Lenkiewicz A, Albrecht J. Reversible decrease of dopamine D2 receptor density in the striatum of rats with acute hepatic failure. Brain Res 2001; 900:143-5. [PMID: 11325357 DOI: 10.1016/s0006-8993(01)02280-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The binding of a D2 receptor ligand, [3H]spiperone, was measured in striatal membranes derived from rats in which acute hepatic failure induced with thioacetamide (TAA) was associated with symptoms of hepatic encephalopathy (HE), and during recovery from HE. A 28% decrease of Bmax for the binding was measured in a symptomatic stage of HE, 1 day after TAA administration. The B(max) for [3H]spiperone binding was no longer different from control 7 days after TAA administration, when blood and brain biochemical correlates of HE were already absent. At 21 days after TAA administration, the B(max) was increased by 31% above the control level, consistent with other aspects of metabolic activation of the brain characteristic of the late recovery period from acute HE.
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Affiliation(s)
- J Waśkiewicz
- Laboratory of CNS Pathobiochemistry, Department of Neurochemistry, Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5, 02-106, Warsaw, Poland
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14
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Borkowska HD, Oja SS, Saransaari P, Albrecht J. Release of [3H]dopamine from striatal and cerebral cortical slices from rats with thioacetamide-induced hepatic encephalopathy: different responses to stimulation by potassium ions and agonists of ionotropic glutamate receptors. Neurochem Res 1997; 22:101-6. [PMID: 9016834 DOI: 10.1023/a:1027347019707] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The effects of depolarizing stimuli; high (50 mM) potassium ions and the glutamate receptor agonists N-methyl-D-aspartate, kainate and 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) on the release of newly-loaded [3H]dopamine were studied in frontal cortical and striatal slices from control rats and from rats with acute hepatic encephalopathy induced with a hepatotoxin, thioacetamide. Hepatic encephalopathy enhanced the stimulatory effect of potassium ions by 20% in striatal slices and by 34% in frontal cortical slices. In striatal slices the stimulatory effects of N-methyl-D-aspartate and kainate were depressed in hepatic encephalopathy by 46% and 21%, respectively, which may be taken to reflect impaired modulation of striatal dopamine release by glutamate acting at N-methyl-D-aspartate or kainate receptors. In frontal cortical slices, the stimulatory effect of kainate was enhanced by 35% in hepatic encephalopathy but N-methyl-D-aspartate-stimulated release was not affected. The release evoked by 2-amino-3-hydroxy-5-methyl-4-isoxazolepropionate was not affected in hepatic encephalopathy in either brain region. Stimulation of dopamine release in the frontal cortex by depolarization or glutamate acting at kainate receptors could inhibit the activity of descending corticostriatal glutamatergic pathways, further impairing regulation of dopamine release by glutamate in the striatum.
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Affiliation(s)
- H D Borkowska
- Tampere Brain Research Center, Department of Biomedical Sciences, University of Tampere, Finland
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15
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Kadoi Y, Saito S. An alteration in the gamma-aminobutyric acid receptor system in experimentally induced septic shock in rats. Crit Care Med 1996; 24:298-305. [PMID: 8605805 DOI: 10.1097/00003246-199602000-00020] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To investigate the role of the brain gamma-aminobutyric acid receptor system in septic shock. DESIGN Prospective, controlled study. SETTING Animal laboratory. SUBJECTS Twenty-one male Wistar rats (7 wks old) were randomized to three groups: group 1 (n = 7, control); group 2 (n = 7, sham-operated); group 3 (n = 7, cecal ligation and puncture group). INTERVENTIONS Under light ether anesthesia, the rats were treated as described above. Twenty-four hours after treatment, the rats were killed by decapitation. Plasma amino acid concentrations were measured using the collected blood. The brain was excised as rapidly as possible, and separated into forebrain, cerebellum, and brain stem. The brain gamma-aminobutyric acid concentration was measured at each of the three regions. Using 3H-musimol, which is a gamma-aminobutyric acid receptor agonist, as a radioligand, the gamma-aminobutyric receptor densities were measured in these three regions by a radio-receptor assay. MEASUREMENTS AND MAIN RESULTS The concentrations of the branch-chain amino acids (leucine, isoleucine, valine) were lower in the cecal ligation and puncture group than in the control and sham operated groups. The concentrations of the sulfur-containing amino acids (cysteine and taurine) were increased in the cecal ligation and puncture group compared with the other two groups, but the methionine concentration was increased in the sham-operated and the cecal ligation and puncture groups compared with the control group (p < .05). The plasma gamma-aminobutyric acid concentration was not detectable in any of the three groups. The ammonia concentration was greater in the cecal ligation and puncture group than in the other two groups. There was no significant difference in the brain gamma-aminobutyric acid concentration among the three groups. The maximum number of binding sites in the forebrain of the cecal ligation and puncture group was higher than in the other two groups at both high- and low-affinity sites (control group: high-affinity sites 0.34 +/- 0.03, low-affinity sites 2.93 +/- 0.28; sham-operated group: high-affinity sites 0.35 +/- 0.03, low-affinity sites 2.73 +/- 0.18; cecal ligation and puncture group: high-affinity sites 0.59 +/- 0.13, low-affinity sites 3.53 +/- 0.21; mean +/- SEM pmol/mg protein) (p < .05). There were no significant differences observed in other regions of the brain (cerebellum and brain stem) in the three groups. The dissociation constants for 3H-musimol were almost unchanged in the three groups. CONCLUSIONS An increase in the gamma-aminobutyric acid-A receptor density was observed in the forebrain of the cecal ligation and puncture model rats. This alteration may be closely related to the pathogenesis of brain dysfunction during septic shock.
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Affiliation(s)
- Y Kadoi
- Department of Anesthesiology and Reanimatology, Gunma University School of Medicine, Japan
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Rothuizen J, de Kok Y, Slob A, Mol JA. GABAergic inhibition of the pituitary release of adrenocorticotropin and alpha-melanotropin is impaired in dogs with hepatic encephalopathy. Domest Anim Endocrinol 1996; 13:59-68. [PMID: 8625616 DOI: 10.1016/0739-7240(95)00044-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
gamma-Aminobutyric acid (GABA) is the principal depressant neurotransmitter system, but its possible role in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) axis has not yet been investigated in the dog. Moreover, GABA is one of the factors underlying the syndrome of hepatic encephalopathy (HE), and in dogs with HE, the regulation of the HPA axis is deranged. We have therefore investigated the role of the GABA system in the regulation of the HPC system in 10 healthy dogs and 10 dogs with HE due to congenital portosystemic shunts. The effect of an intravenous injection of the GABA antagonist bicuculline on the release of adrenocorticotropin (ACTH), alpha-melanotropin (MSH), and cortisol was measured in plasma. In healthy dogs, a dose of 1.0 mg/kg caused a marked release of ACTH, MSH, and cortisol, but doses of 0.001 to 0.5 mg/kg produced an inconsistent or no response. The high release of MSH after bicuculline administration indicated that the effect of GABA was predominantly in the neurointermediate lobe of the pituitary. In order to investigate whether the effect of GABA was exerted in the pituitary or at a suprapituitary level, the effect of incubation with GABA on basal and corticotropin-releasing hormone-induced ACTH release was measured in primary cultures of anterior and neurointermediate lobe cells from healthy dogs, and no response was observed. We conclude that in healthy dogs, GABA inhibits the release of ACTH and MSH from the neurointermediate lobe of the pituitary at a suprapituitary level. In dogs with HE, 1.0 mg/kg of bicuculline caused virtually no stimulation of the secretion of ACTH, MSH, or cortisol, indicating deranged GABAergic neurotransmission in HE. This may be explained by an increased GABA tone that prevents the effect of the antagonist. Such a high GABA tone associated with HE has been documented in several other species. Dogs with HE had significantly increased basal levels of ACTH, MSH, and cortisol in plasma, and their cortisol:creatinine ratios in 24-hr urine samples (63 +/- 14.10(-6)) were higher than those of healthy dogs (9 +/- 2.10(-6)). An increased basal HPA activity in dogs with HE is not in agreement with augmented GABAergic inhibition, but this contradiction may be explained by the predominance of effects of dopaminergic disinhibition that has been reported in such dogs.
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Affiliation(s)
- J Rothuizen
- Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, University of Utrecht, The Netherlands
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Komatsubara T, Kadoi Y, Saito S. Augmented sensitivity to benzodiazepine in septic shock rats. Can J Anaesth 1995; 42:937-43. [PMID: 8706205 DOI: 10.1007/bf03011043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The purpose of this study was to assess the pharmacological characteristics of the benzodiazepine binding site in the brain of septic animals. We induced endotoxin shock in rats using a caecum ligation and puncture model. Following examination of the physiological state of the rats 24 hr after the caecum ligation and puncture, brain tissue samples were prepared for biochemical assay of amino acids and for the [3H]-diazepam radioligand binding assay. Amino acids assays indicated that the concentration of aromatic amino acids was higher in the CLP group (P< 0.05), the branched chain amino acid concentration was lower in the CLP group (P< 0.05) and the sulfur-containing amino acid concentration was elevated in the CLP group (P< 0.05) than in both the control and the sham-operated groups. [3H]-diazepam radioligand binding assays demonstrated that the number of receptors in the septic rats was increased in the forebrain (CLP rats; 2.37 +/- 0.04 pmol x mg(-1) protein, control rats; 1.45 +/- 0.02 pmol x mg(-1) protein, sham-operated rats; 1.49 +/- 0.03 pmol x mg(-1) protein), cerebellum (CLP rats; 1.55 +/- 0.05 pmol x mg(-1) protein, control rats; 1.05 +/- 0.02 pmol x mg(-1) protein, sham-operated rats: 1.09 +/- 0.02 pmol x mg(-1) protein) and brain stem (CLP rats; 1.21 +/- 0.04 pmol x mg(-1) protein, control rats; 0.61 +/- 0.02 pmol x mg(-1) protein, sham-operated rats; 0.63 +/- 0.02 pmol x mg(-1) protein) compared with the control and sham-operated rats (P< 0.05). In conclusion, it was considered that the increased number of benzodiazepine receptors may be one cause of the neuronal alteration observed in septic shock animals.
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Affiliation(s)
- T Komatsubara
- Department of Anesthesiology and Reanimatology, Gunma University School of Medicine, Maebashi, Japan
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Mullen KD, Birgisson S, Gacad RC, Conjeevaram H. Animal models of hepatic encephalopathy and hyperammonemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 368:1-10. [PMID: 7740998 DOI: 10.1007/978-1-4615-1989-8_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Animal models of chronic liver disease with hyperammonemia are currently available to investigators. Two in particular have been utilized extensively. Carbon tetrachloride induced (CCl4) cirrhosis in the rat and portacaval shunt in the same species and other animals particularly the dog. In regards to hepatic encephalopathy, however, the CCl4 cirrhosis rat model seems to display few behavioral changes unless very advanced decompensated cirrhosis is produced. Further work should be done on this model to verify the development of encephalopathy and to improve reproducibility. The portacaval shunt rat on the other hand clearly has a consistent albeit subtle set of behavioral changes. Recent improvements in detecting these changes and more importantly showing reversal or improvement by neomycin or a low protein diet are a major advance. Hopefully, more laboratories will be able to reproduce this reversible change in behavior. Experiences gained from 7 years of using the portacaval shunt rat and other models of liver disease are described.
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Affiliation(s)
- K D Mullen
- Division of Gastroenterology MetroHealth Medical Center Case Western Reserve University Cleveland, Ohio, USA
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Mousseau DD, Perney P, Layrargues GP, Butterworth RF. Selective loss of pallidal dopamine D2 receptor density in hepatic encephalopathy. Neurosci Lett 1993; 162:192-6. [PMID: 8121627 DOI: 10.1016/0304-3940(93)90593-a] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The binding parameters of [3H]SCH 23390 and [3H]spiperone (radioligands for dopamine D1 and D2 receptors, respectively) were investigated in autopsied frontal cortex, caudate nucleus and globus pallidus/putamen of cirrhotic patients who died in hepatic coma as well as in age- and sex-matched controls. Specific [3H]SCH 23390 binding site densities were unchanged in all regions; in contrast, specific [3H]spiperone binding site density was decreased (by 44%, P < 0.001) in the globus pallidus/putamen of patients with HE. Decreased densities of pallidal D2 binding sites could relate to the motor dysfunctions commonly encountered in human HE.
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Affiliation(s)
- D D Mousseau
- Neuroscience Research Unit, Hôpital St-Luc, University of Montreal, Que., Canada
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Wysmyk U, Oja SS, Saransaari P, Albrecht J. Enhanced GABA release in cerebral cortical slices derived from rats with thioacetamide-induced hepatic encephalopathy. Neurochem Res 1992; 17:1187-90. [PMID: 1461366 DOI: 10.1007/bf00968397] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The release of newly loaded [3H]GABA was studied in slices of different brain regions derived from rats in which acute hepatic encephalopathy (HE) was induced with a hepatotoxin thioacetamide. HE increased both spontaneous and high (50 mM) ammonium chloride-evoked GABA release in cerebral cortical slices by 38% and 50%, respectively. No effects of HE were noted in cerebellar or striatal slices. An increased release of GABA in the cerebral cortex may contribute to the endogenous benzodiazepine-mediated enhancement of GABAergic tone, which is thought to be partly responsible for the pathophysiological mechanism of HE.
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Affiliation(s)
- U Wysmyk
- Department of Biomedical Sciences, University of Tampere, Finland
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Abstract
Hepatic encephalopathy occurs in a number of different species as a result of either congenital portacaval shunts or acquired liver disease. Despite intensive research, the neurochemical basis of the disorder has not been defined. Theories to explain the cerebral dysfunction that accompanies acute or chronic hepatic failure include 1) ammonia acting as the putative neurotoxin, 2) perturbed monoamine neurotransmission as a result of altered plasma amino acid metabolism, 3) an imbalance between excitatory amino acid neurotransmission, mediated by glutamate, and inhibitory amino acid neurotransmission, mediated by gamma-aminobutyric acid, and 4) increased cerebral concentrations of an endogenous benzodiazepine-like substance.
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Affiliation(s)
- J E Maddison
- Department of Pharmacology, University of Sydney, Australia
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Maddison JE. Neurochemical studies of hepatic encephalopathy. Drug Alcohol Rev 1992; 11:393-400. [PMID: 16840096 DOI: 10.1080/09595239200185531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Despite intensive research, the neurochemical basis of hepatic encephalopathy (HE) has not been defined. Theories that are currently favoured to explain the cerebral dysfunction that accompanies acute or chronic hepatic failure include: (1) ammonia acting as the putative neurotoxin; (2) perturbed monoamine neutrotransmission as a result of altered plasmo amino acid metabolism; (3) an imbalance between excitatory amino acid neurotransmission, mediated by glutamate, and inhibitory amino acid neurotransmission, mediated by gamma-aminobutyric acid (GABA); and (4) increased cerebral concentrations of an endogenous benzodiazepine-like substance. Studies of amino acid neurotransmitter receptors in HE have yielded conflicting results. The majority of studies in different animal models of acute and chronic HE and in patients have reported that brain GABA receptor density and affinity are unchanged. There have been fewer studies of excitatory amino acid receptors and these have also yielded conflicting results. However, the majority suggest that components of the glutamate receptor system are perturbed in HE. Further investigation is required to determine the significance of these findings to the pathogenesis of HE.
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Affiliation(s)
- J E Maddison
- Department of Pharmacology, The University of Sydney, NSW, 2006, Australia
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