Reduced brain Na+,K+-ATPase activity in rats with galactosamine-induced hepatic failure: relationship to encephalopathy and cerebral oedema

1987 ◽  
Vol 72 (3) ◽  
pp. 365-371 ◽  
Author(s):  
Roland J. Ede ◽  
Christopher D. Gove ◽  
Robin D. Hughes ◽  
William Marshall ◽  
Roger Williams
Keyword(s):  
Atpase Activity ◽  
Rat Brain ◽  
Hepatic Failure ◽  
Cerebral Oedema ◽  
Toxic Substance ◽  
Clear Correlation ◽  
Sodium Efflux ◽  
Normal Rat

1. Previously we have shown that sera from patients with fulminant hepatic failure (FHF) will inhibit partially purified rat brain Na+,K+-ATPase and sodium efflux from human leucocytes in vitro. Similar inhibition may be involved in the pathogenesis of encephalopathy and cerebral oedema in these patients. 2. In the present study we have attempted to establish whether the activity of brain Na+,K+-ATPase is decreased in vivo in rats with d-galactosamine induced hepatic failure using homogenates of snap-frozen brains. 3. Na+,K+-ATPase activity was significantly reduced in the forebrain region at the stage of mild encephalopathy (43 h after injection), while at the deeper stage of coma (43–53 h after injection) enzyme activity was further reduced in the forebrain region and was also significantly reduced in the hindbrain region. Ouabain insensitive ATPase activity was not significantly altered at any time. 4. While a significant increase in the water content (0.5%) of the hindbrain region was found 43 h after galactosamine, there was no clear correlation between the development of cerebral oedema and the reduction of Na+,K+-ATPase activity. 5. The activity of partially purified normal rat brain Na+,K+-ATPase was 15% lower when incubated with sera from rats in the deep stage of coma compared with control sera. 6. These data support other evidence that the reduction in brain Na+,K+-ATPase is likely to be due to toxic substance circulating in serum which have been shown to inhibit this enzyme in vitro and to cause coma when administered to normal animals.

Effects of Serum from Patients with Fulminant Hepatic Failure on Leucocyte Sodium Transport

1982 ◽  
Vol 63 (3) ◽  
pp. 237-242 ◽  
Author(s):  
R. B. Sewell ◽  
R. D. Hughes ◽  
Lucilla Poston ◽  
Roger Williams
Keyword(s):  
Fulminant Hepatic Failure ◽  
Sodium Transport ◽  
Hepatic Failure ◽  
Elution Profile ◽  
Sodium Efflux ◽  
Polyacrylonitrile Membrane ◽  
Normal Controls

1. Serum from patients with fulminant hepatic failure inhibits the ouabain-sensitive sodium efflux in leucocytes. A 1:100 dilution of the serum was necessary before the inhibition became undetectable. 2. Dialysates of the serum through cuprophane in vitro and polyacrylonitrile haemodialysis in vivo were inhibitory in small amounts. 3. Ultrafiltrates (<10 000 daltons) of serum were chromatographed on Sephadex G-25 and the elution profile obtained from patients with fulminant hepatic failure was both qualitatively and quantitatively different from that of normal controls. Material from peaks 3, 4, 5 and 7 in patients with fulminant hepatic failure inhibited leucocyte sodium transport. 4. The dialysate from haemodialysis with the polyacrylonitrile membrane contained most peaks, particularly peaks 4 and 5. Adsorption of serum with polymer coated charcoal in vitro largely removed peaks 5−8.

Effect of penol on the GABA receptor-coupled Cl/HCO-ATPase from rat brain in / experiments

2018 ◽  
pp. 48-52
Author(s):  
С.А. Мензиков
Keyword(s):  
Rat Brain ◽  
Gaba Receptor ◽  
Plasma Membranes ◽  
Molecular Mechanisms ◽  
Toxic Substance ◽  
Clinical Signs ◽  
Neuronal Membranes

Фенол (гидроксибензол) является токсичным веществом. Одним из клинических признаков проявления эффекта высоких доз фенола на животных является судорожная активность, молекулярные механизмы которой остаются неясными. Цель исследования - изучение молекулярных механизмов судорожной активности при действии токсиканта (фенол) с нервно-паралитической природой действия. Методика. Исследована роль Cl/HCO-АТФазы, которая участвует в ГАМК рецептор-сопряженном АТФ-зависимом Cl-транспорте через нейрональные мембраны мозга животных. Результаты. Исследования in vivo показали, что после внутрибрюшинной инъекции животным фенола (300 мг/кг) наблюдается судорожная реакция, при этом АТФазная активность мозга крыс не выявляется. В экспериментах in vitro установлено, что фенол (500 мкМ) полностью ингибирует функциональную активность Cl/HCO-АТФазы нейрональных мембран мозга крыс. Заключение. Делается вывод о важной роли нейрональной Cl/HCO-АТФазы в патогенезе и проявлении судорожных ответов у животных. Phenol (hydroxybenzene) is a toxic substance with a neuroparalytic nature of action. One of the clinical signs of the manifestation of the effect high doses of phenol on animals is convulsive activity, the molecular mechanisms of which remain unclear. Aim. In order to clarify these mechanisms, in the present work we investigated the role of Cl/HCO-ATPase, which is involved in GABA receptor-coupled ATP-dependent Cl-transport through the plasma membranes of the neurons of animals brain. Results. In vivo studies have been shown that after intraperitoneal injection of phenol at a dose of 300 mg/kg to the animals, a convulsive reaction is observed, while the Cl/HCO-ATPase of the rat brain is not detected. In in vitro experiments, it was established that phenol (500 мM) completely inhibits the functional activity of the Cl/HCO-ATPase of the neuronal membranes from rat brain. It was assumed the important role of neuronal Cl/HCO-ATPase in the pathogenesis of phenolic neurotoxicity and the manifestation of convulsive responses in animals.

scholarly journals High Glycogen Levels in Brains of Rats with Minimal Environmental Stimuli: Implications for Metabolic Contributions of Working Astrocytes

2002 ◽  
Vol 22 (12) ◽  
pp. 1476-1489 ◽  
Author(s):  
Nancy F. Cruz ◽  
Gerald A. Dienel
Keyword(s):  
Rat Brain ◽  
Sensory Stimulation ◽  
Enzyme Inactivation ◽  
Biologically Active ◽  
Metabolic Labeling ◽  
Tissue Sampling ◽  
Normal Rat ◽  
Sampling Procedures ◽  
Very High

The concentration of glycogen, the major brain energy reserve localized mainly in astrocytes, is generally reported as about 2 or 3 μmol/g, but sometimes as high as 3.9 to 8 μmol/g, in normal rat brain. The authors found high but very different glycogen levels in two recent studies in which glycogen was determined by the routine amyloglucosidase procedure in 0.03N HCl digests either of frozen powders (4.8 to 6 μmol/g) or of ethanol-insoluble fractions (8 to 12 μmol/g). To evaluate the basis for these discrepant results, glycogen was assayed in parallel extracts of the same samples. Glycogen levels in ethanol extracts were twice those in 0.03N HCl digests, suggesting incomplete enzyme inactivation even with very careful thawing. The very high glycogen levels were biologically active and responsive to physiologic and pharmacological challenge. Glycogen levels fell after brief sensory stimulation, and metabolic labeling indicated its turnover under resting conditions. About 95% of the glycogen was degraded under in vitro ischemic conditions, and its “carbon equivalents” recovered mainly as glc, glc-P, and lactate. Resting glycogen stores were reduced by about 50% by chronic inhibition of nitric oxide synthase. Because neurotransmitters are known to stimulate glycogenolysis, stress or sensory activation due to animal handling and tissue-sampling procedures may stimulate glycogenolysis during an experiment, and glycogen lability during tissue sampling and extraction can further reduce glycogen levels. The very high glycogen levels in normal rat brain suggest an unrecognized role for astrocytic energy metabolism during brain activation.

scholarly journals Phosphorylation-dependent interaction of the synaptic vesicle proteins cysteine string protein and synaptotagmin I

2002 ◽  
Vol 364 (2) ◽  
pp. 343-347 ◽  
Author(s):  
Gareth J.O. EVANS ◽  
Alan MORGAN
Keyword(s):  
Rat Brain ◽  
Direct Interaction ◽  
Secretory Vesicle ◽  
Brain Membrane ◽  
Synaptotagmin I ◽  
Phosphorylated Form ◽  
Order Of Magnitude ◽  
And Function

The secretory vesicle cysteine string proteins (CSPs) are members of the DnaJ family of chaperones, and function at late stages of Ca2+-regulated exocytosis by an unknown mechanism. To determine novel binding partners of CSPs, we employed a pull-down strategy from purified rat brain membrane or cytosolic proteins using recombinant hexahistidine-tagged (His6-)CSP. Western blotting of the CSP-binding proteins identified synaptotagmin I to be a putative binding partner. Furthermore, pull-down assays using cAMP-dependent protein kinase (PKA)-phosphorylated CSP recovered significantly less synaptotagmin. Complexes containing CSP and synaptotagmin were immunoprecipitated from rat brain membranes, further suggesting that these proteins interact in vivo. Binding assays in vitro using recombinant proteins confirmed a direct interaction between the two proteins and demonstrated that the PKA-phosphorylated form of CSP binds synaptotagmin with approximately an order of magnitude lower affinity than the non-phosphorylated form. Genetic studies have implicated each of these proteins in the Ca2+-dependency of exocytosis and, since CSP does not bind Ca2+, this novel interaction might explain the Ca2+-dependent actions of CSP.

scholarly journals Dissection of Swa2p/Auxilin Domain Requirements for Cochaperoning Hsp70 Clathrin-uncoating Activity In Vivo

2006 ◽  
Vol 17 (7) ◽  
pp. 3281-3290 ◽  
Author(s):  
Jing Xiao ◽  
Leslie S. Kim ◽  
Todd R. Graham
Keyword(s):  
Atpase Activity ◽  
Point Mutation ◽  
Mutational Analysis ◽  
Weak Interactions ◽  
Tetratricopeptide Repeat ◽  
Uba Domain ◽  
J Domain ◽  
Tpr Domain

The auxilin family of J-domain proteins load Hsp70 onto clathrin-coated vesicles (CCVs) to drive uncoating. In vitro, auxilin function requires its ability to bind clathrin and stimulate Hsp70 ATPase activity via its J-domain. To test these requirements in vivo, we performed a mutational analysis of Swa2p, the yeast auxilin ortholog. Swa2p is a modular protein with three N-terminal clathrin-binding (CB) motifs, a ubiquitin association (UBA) domain, a tetratricopeptide repeat (TPR) domain, and a C-terminal J-domain. In vitro, clathrin binding is mediated by multiple weak interactions, but a Swa2p truncation lacking two CB motifs and the UBA domain retains nearly full function in vivo. Deletion of all CB motifs strongly abrogates clathrin disassembly but does not eliminate Swa2p function in vivo. Surprisingly, mutation of the invariant HPD motif within the J-domain to AAA only partially affects Swa2p function. Similarly, a TPR point mutation (G388R) causes a modest phenotype. However, Swa2p function is abolished when these TPR and J mutations are combined. The TPR and J-domains are not functionally redundant because deletion of either domain renders Swa2p nonfunctional. These data suggest that the TPR and J-domains collaborate in a bipartite interaction with Hsp70 to regulate its activity in clathrin disassembly.

scholarly journals A SPECIFIC POISON IN THE LIVER EXTRACTS OF RABBITS INOCULATED WITH TYPHOID AND PRODIGIOSUS BACILLI INTRAVENOUSLY

1918 ◽  
Vol 28 (5) ◽  
pp. 571-583
Author(s):  
Julia T. Parker
Keyword(s):  
Anaphylactic Shock ◽  
Liver Extract ◽  
Lethal Dose ◽  
Toxic Substance ◽  
Normal Liver ◽  
Immune Serum ◽  
Minimum Lethal Dose ◽  
Lethal Doses

1. The livers of rabbits inoculated with cultures of Bacillus typhosus or Bacillus prodigiosus under certain conditions contain a toxic substance extractable with salt solution. When the toxic extracts are injected intravenously into normal rabbits the latter animals develop symptoms resembling those of anaphylactic shock and succumb. The lethal doses of the toxic extracts are far smaller than those of normal liver extract. 2. The livers of rabbits injected with typhoid antigen also yield a toxic extract. 3. Boiling as well as filtration through a Berkefeld filter only partially detoxicates the extract. 4. Tolerance to one to two lethal doses of the poisonous extracts can be induced by cautious immunization. 5. Rabbits actively immunized to Bacillus typhosus or Bacillus prodigiosus usually resist one lethal dose of the homologous liver poison; and animals tolerant to the typhoid liver poison resist one minimum lethal dose at least of Bacillus typhosus. 6. Typhoid immune serum is not detoxicating either in vivo or in vitro for the typhoid liver poison. 7. The liver poisons are specific, since rabbits actively immunized to either Bacillus typhosus or Bacillus prodigiosus withstand at least one minimum lethal dose of the homologous but not of the heterologous-liver poisons.

In vitro and in vivo depolarization coupled efflux of ascorbic acid in rat brain preparations

1981 ◽  
Vol 7 (3) ◽  
pp. 237-242 ◽  
Author(s):  
Kristin H. Milby ◽  
Ivan N. Mefford ◽  
Willie Chey ◽  
Ralph N. Adams
Keyword(s):  
Ascorbic Acid ◽  
Rat Brain

Metabolic importance of Na+/K+-ATPase activity during sea urchin development.

1997 ◽  
Vol 200 (22) ◽  
pp. 2881-2892 ◽  
Author(s):  
P Leong ◽  
D Manahan
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Sea Urchin ◽  
Sodium Pump ◽  
Sea Water ◽  
Strongylocentrotus Purpuratus ◽  
Lytechinus Pictus ◽  
Stimulation Of

Early stages of animal development have high mass-specific rates of metabolism. The biochemical processes that establish metabolic rate and how these processes change during development are not understood. In this study, changes in Na+/K+-ATPase activity (the sodium pump) and rate of oxygen consumption were measured during embryonic and early larval development for two species of sea urchin, Strongylocentrotus purpuratus and Lytechinus pictus. Total (in vitro) Na+/K+-ATPase activity increased during development and could potentially account for up to 77 % of larval oxygen consumption in Strongylocentrotus purpuratus (pluteus stage) and 80 % in Lytechinus pictus (prism stage). The critical issue was addressed of what percentage of total enzyme activity is physiologically active in living embryos and larvae and thus what percentage of metabolism is established by the activity of the sodium pump during development. Early developmental stages of sea urchins are ideal for understanding the in vivo metabolic importance of Na+/K+-ATPase because of their small size and high permeability to radioactive tracers (86Rb+) added to sea water. A comparison of total and in vivo Na+/K+-ATPase activities revealed that approximately half of the total activity was utilized in vivo. The remainder represented a functionally active reserve that was subject to regulation, as verified by stimulation of in vivo Na+/K+-ATPase activity in the presence of the ionophore monensin. In the presence of monensin, in vivo Na+/K+-ATPase activities in embryos of S. purpuratus increased to 94 % of the maximum enzyme activity measured in vitro. Stimulation of in vivo Na+/K+-ATPase activity was also observed in the presence of dissolved alanine, presumably due to the requirement to remove the additional intracellular Na+ that was cotransported with alanine from sea water. The metabolic cost of maintaining the ionic balance was found to be high, with this process alone accounting for 40 % of the metabolic rate of sea urchin larvae (based on the measured fraction of total Na+/K+-ATPase that is physiologically active in larvae of S. purpuratus). Ontogenetic changes in pump activity and environmentally induced regulation of reserve Na+/K+-ATPase activity are important factors that determine a major proportion of the metabolic costs of sea urchin development.

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