scholarly journals K+-p-nitrophenylphosphatase activity in rat brain and liver

2009 ◽  
pp. 121-126
Author(s):  
M Ďurfinová ◽  
M Brechtlová ◽  
B Líška ◽  
Ž Barošková
Keyword(s):  
Rat Brain ◽  
Brain Activity ◽  
Brain Homogenate ◽  
Whole Brain ◽  
Pellet Fraction ◽  
Total Brain ◽  
Rat Brain And Liver ◽  
Protein Rich ◽  
The Brain

K+-p-nitrophenylphosphatase (K+pNPPase) is the enzyme, which is considered to be involved in K+-dependent hydrolysis of the phosphoenzyme in the reaction cycle of Na+, K+-ATPase. The aim of our present study was to characterize some features of K+pNPPase in homogenates of the rat brain and liver. We determined p-nitrophenylphosphatase (pNPPase) activity in the presence of various ion combinations (Mg2++K+, Mg2+, K+). We found a higher total pNPPase activity in the brain (0.8±0.079 nkat/mg protein) than in the liver (0.08±0.01 nkat/mg protein). Contrary to the liver, the main part of the total brain activity was K+-dependent. The activity of K+pNPPase was significantly higher in cerebral cortex homogenates (0.86±0.073 nkat/mg protein) in comparison to those of the whole brain (0.57±0.075 nkat/mg protein). The specific K+pNPPase activity was two times higher in the isolated pellet fraction (0.911±0.07 nkat/mg protein), rich in synaptosomes, compared to the whole brain homogenate (0.57±0.075 nkat/mg protein). Our results demonstrate the high activity of K+pNPPase in the brain tissue and its distribution mainly into the pellet fraction, what might indicate a possible role of K+pNPPase in specific structures of the brain, e.g. in synaptosomes.

scholarly journals Cholinergic neuromodulation of inhibitory interneurons facilitates functional integration in whole-brain models

2021 ◽  
Vol 17 (2) ◽  
pp. e1008737
Author(s):  
Carlos Coronel-Oliveros ◽  
Rodrigo Cofré ◽  
Patricio Orio
Keyword(s):  
Computational Models ◽  
Functional Organization ◽  
Brain Activity ◽  
Functional Integration ◽  
Whole Brain ◽  
Inhibitory Circuits ◽  
Inhibitory Feedback ◽  
Biophysical Mechanism ◽  
The Brain

Segregation and integration are two fundamental principles of brain structural and functional organization. Neuroimaging studies have shown that the brain transits between different functionally segregated and integrated states, and neuromodulatory systems have been proposed as key to facilitate these transitions. Although whole-brain computational models have reproduced this neuromodulatory effect, the role of local inhibitory circuits and their cholinergic modulation has not been studied. In this article, we consider a Jansen & Rit whole-brain model in a network interconnected using a human connectome, and study the influence of the cholinergic and noradrenergic neuromodulatory systems on the segregation/integration balance. In our model, we introduce a local inhibitory feedback as a plausible biophysical mechanism that enables the integration of whole-brain activity, and that interacts with the other neuromodulatory influences to facilitate the transition between different functional segregation/integration regimes in the brain.

scholarly journals Consciousness, decision making, and volition: freedom beyond chance and necessity

2021 ◽  
Author(s):  
Hans Liljenström
Keyword(s):  
Decision Making ◽  
Free Will ◽  
Brain Activity ◽  
Brain Structures ◽  
Complex Process ◽  
Neural Information ◽  
Neural Information Processing ◽  
Stochastic Population Model ◽  
The Brain

AbstractWhat is the role of consciousness in volition and decision-making? Are our actions fully determined by brain activity preceding our decisions to act, or can consciousness instead affect the brain activity leading to action? This has been much debated in philosophy, but also in science since the famous experiments by Libet in the 1980s, where the current most common interpretation is that conscious free will is an illusion. It seems that the brain knows, up to several seconds in advance what “you” decide to do. These studies have, however, been criticized, and alternative interpretations of the experiments can be given, some of which are discussed in this paper. In an attempt to elucidate the processes involved in decision-making (DM), as an essential part of volition, we have developed a computational model of relevant brain structures and their neurodynamics. While DM is a complex process, we have particularly focused on the amygdala and orbitofrontal cortex (OFC) for its emotional, and the lateral prefrontal cortex (LPFC) for its cognitive aspects. In this paper, we present a stochastic population model representing the neural information processing of DM. Simulation results seem to confirm the notion that if decisions have to be made fast, emotional processes and aspects dominate, while rational processes are more time consuming and may result in a delayed decision. Finally, some limitations of current science and computational modeling will be discussed, hinting at a future development of science, where consciousness and free will may add to chance and necessity as explanation for what happens in the world.

scholarly journals Neuronal spreading and plaque induction of intracellular Aβ and its disruption of Aβ homeostasis

2021 ◽  
Author(s):  
Tomas T. Roos ◽  
Megg G. Garcia ◽  
Isak Martinsson ◽  
Rana Mabrouk ◽  
Bodil Israelsson ◽  
...  
Keyword(s):  
Brain Homogenate ◽  
Fold Increase ◽  
Amyloid Beta Peptide ◽  
Intracellular Accumulation ◽  
Brain Areas ◽  
Cellular Models ◽  
Beta Peptide ◽  
The Brain

AbstractThe amyloid-beta peptide (Aβ) is thought to have prion-like properties promoting its spread throughout the brain in Alzheimer’s disease (AD). However, the cellular mechanism(s) of this spread remains unclear. Here, we show an important role of intracellular Aβ in its prion-like spread. We demonstrate that an intracellular source of Aβ can induce amyloid plaques in vivo via hippocampal injection. We show that hippocampal injection of mouse AD brain homogenate not only induces plaques, but also damages interneurons and affects intracellular Aβ levels in synaptically connected brain areas, paralleling cellular changes seen in AD. Furthermore, in a primary neuron AD model, exposure of picomolar amounts of brain-derived Aβ leads to an apparent redistribution of Aβ from soma to processes and dystrophic neurites. We also observe that such neuritic dystrophies associate with plaque formation in AD-transgenic mice. Finally, using cellular models, we propose a mechanism for how intracellular accumulation of Aβ disturbs homeostatic control of Aβ levels and can contribute to the up to 10,000-fold increase of Aβ in the AD brain. Our data indicate an essential role for intracellular prion-like Aβ and its synaptic spread in the pathogenesis of AD.

Is Artistic Composition in Abstract Art Detected Automatically?

2021 ◽  
pp. 102-106
Author(s):  
Claudia Menzel ◽  
Gyula Kovács ◽  
Gregor U. Hayn-Leichsenring ◽  
Christoph Redies
Keyword(s):  
Human Brain ◽  
Significant Role ◽  
Mismatch Negativity ◽  
Brain Activity ◽  
Perceptual Processing ◽  
Abstract Art ◽  
Electrical Brain Activity ◽  
Image Set ◽  
The Brain

Most artists who create abstract paintings place the pictorial elements not at random, but arrange them intentionally in a specific artistic composition. This arrangement results in a pattern of image properties that differs from image versions in which the same pictorial elements are randomly shuffled. In the article under discussion, the original abstract paintings of the author’s image set were rated as more ordered and harmonious but less interesting than their shuffled counterparts. The authors tested whether the human brain distinguishes between these original and shuffled images by recording electrical brain activity in a particular paradigm that evokes a so-called visual mismatch negativity. The results revealed that the brain detects the differences between the two types of images fast and automatically. These findings are in line with models that postulate a significant role of early (low-level) perceptual processing of formal image properties in aesthetic evaluations.

SUPER-SYNERGY IN THE BRAIN: THE GRANDMOTHER PERCEPT IS MANIFESTED BY MULTIPLE OSCILLATIONS

2004 ◽  
Vol 14 (02) ◽  
pp. 453-491 ◽  
Author(s):  
EROL BAŞAR ◽  
MURAT ÖZGÖREN ◽  
SIREL KARAKAŞ ◽  
CANAN BAŞAR-EROĞLU
Keyword(s):  
Experimental Work ◽  
Brain Function ◽  
Present Report ◽  
Whole Brain ◽  
Animal Brain ◽  
Oscillatory Dynamics ◽  
New Research ◽  
The Brain ◽  
Face Support

The present report describes the dynamic foundations of long-standing experimental work in the field of oscillatory dynamics in the human and animal brain. It aims to show the role of multiple oscillations in the integrative brain function, memory, and complex perception by a recently introduced conceptional framework: the super-synergy in the whole brain. Results of recent experiments related to the percept of the grandmother-face support our concept of super-synergy in the whole brain in order to explain manifestation of Gestalts and Memory-Stages. This report may also provide new research avenues in macrodynamics of the brain.

Subcellular Distribution of DNA Polymerase Activity in Newborn Rat Brain and Liver

1971 ◽  
Vol 49 (12) ◽  
pp. 1285-1291 ◽  
Author(s):  
M. R. V. Murthy ◽  
A. D. Bharucha
Keyword(s):  
Enzyme Activity ◽  
Rat Brain ◽  
Dna Polymerase ◽  
Subcellular Fraction ◽  
Polymerase Activity ◽  
Particulate Material ◽  
Newborn Rat ◽  
Newborn Brain ◽  
Rat Brain And Liver ◽  
The Brain

DNA polymerase activities were determined in the cytoplasmic soluble, the nuclear soluble, and the nuclear particulate fractions of newborn rat brain and liver. The results indicate that a majority of the brain nuclear enzyme may be bound to particulate material while a majority of the liver nuclear enzyme may be free or only loosely bound. Although the subcellular distributions of DNA polymerase activity are widely different in newborn brain and liver, the enzyme activity in any given subcellular fraction is higher in liver than in brain.

The Prognosis in Insanity

1883 ◽  
Vol 29 (126) ◽  
pp. 188-205
Author(s):  
D. G. Thomson
Keyword(s):  
Complete Resolution ◽  
Brain Activity ◽  
The State ◽  
Point Of View ◽  
Whole Brain ◽  
Increased Activity ◽  
The Brain ◽  
Abnormal Tissue

Mental Exaltation, Mania.—The question of the Prognosis in Mental Exaltation—Mania—in its various forms, is a far more debatable and uncertain matter than in melancholia. The symptoms in melancholia being of a negative character due to a lowering or suspension of brain activity, we do not look for all those diversities, endless varieties and aspects which we may find in mania, be it simple, acute, or chronic. Generally there is an increased vitality, a state of hyperæsthesia, an increase in the activity of the brain, generally of the whole brain, and we must believe that these states will not so easily end in complete resolution as the condition of merely depressed action, or rather no action, which obtains in melancholia—I mean in melancholia generally, and not those states of acute melancholia which are supposed to be closely allied to the state which in other brains and under other subjective circumstances would give rise to mania from a pathological point of view. If this increased activity does not rapidly terminate in resolution, one of two things must occur—either exhaustion or atrophy, resulting in death or dementia, will supervene, or abnormal tissue will invade or replace healthy nerve paths or areas, and chronic aberration of mind ensue.

scholarly journals The Retention Mechanism of Technetium-99m-HM-PAO: Intracellular Reaction with Glutathione

1988 ◽  
Vol 8 (1_suppl) ◽  
pp. S4-S12 ◽  
Author(s):  
Rudi D. Neirinckx ◽  
James F. Burke ◽  
Roger C. Harrison ◽  
Alan M. Forster ◽  
Allan R. Andersen ◽  
...  
Keyword(s):  
Steady State ◽  
Tissue Distribution ◽  
Rat Brain ◽  
Rate Constant ◽  
Conversion Rate ◽  
Brain Homogenate ◽  
Retention Mechanism ◽  
Technetium 99M ◽  
The Brain

Preparations of d,l- and meso-hexamethylpropyleneamine oxime (HM-PAO) labeled with technetium-99m were added to rat brain homogenates diluted with phosphate buffer (l: 10). The conversion of d,l-HM-PAO to hydrophilic forms took place with an initial rate constant of 0.12 min−1. Incubation of the brain homogenate with 2% diethyl maleate for 5 h decreased the homogenate's measured glutathione (GSH) concentration from 160 to 16 μ M and decreased the conversion rate to 0.012 min−1. Buffered aqueous solutions of glutathione rapidly converted the HM-PAO tracers to hydrophilic forms having the same chromatographic characteristics as found in the brain homogenates. The rate constant for the conversion reaction of d,l-HM-PAO in GSH aqueous solution was 208 and 317 L/mol/min in two different assay systems and for meso-HM-PAO the values were 14.7 and 23.2 L/mol/min, respectively. Rat brain has a GSH concentration of about 2.3 m M and the conversion of the d,l-HM-PAO due to GSH alone should proceed with a rate constant of 0.48 to 0.73 min−1 and be correspondingly 14-fold slower for meso-HM-PAO. In human brain, the in vivo data of Lassen et al. show a conversion rate constant of 0.80 min−1. This correspondence of values supports the notion that GSH may be important for the in vivo conversion of 99mTc-labeled HM-PAO to hydrophilic forms and may be the mechanism of trapping in brain and other cells. A kinetic model for the trapping of d,l- and meso-HM-PAO in tissue is developed that is based on data of GSH concentration in various organs. This model predicts that the d,l form rapidly reaches a steady state in tissue and the tissue distribution reflects a pattern dominated by blood flow. For the meso form, the model predicts that steady state is reached more slowly and the tissue distribution reflects a pattern dominated by glutathione concentration.

Role of Microsomal Oxidation in Regulation of Monoamine Oxidase Activity in Rat Brain and Liver

2016 ◽  
Vol 71 ◽  
pp. 50
Author(s):  
Olga Tseylikman ◽  
Vadim Tseilikman ◽  
Eugenia Manukhina ◽  
Fred Downey ◽  
Mariya Komelkova ◽  
...  
Keyword(s):  
Monoamine Oxidase ◽  
Rat Brain ◽  
Oxidase Activity ◽  
Monoamine Oxidase Activity ◽  
Microsomal Oxidation ◽  
Rat Brain And Liver

scholarly journals Curcumin Reduce Sodium Fluoride-Induced Oxidative Stress in Rat Brain

2018 ◽  
Vol 15 (1) ◽  
pp. 71-77 ◽  
Author(s):  
Nagapuri Kiran Kumar ◽  
Mesram Nageshwar ◽  
Karnati Pratap Reddy
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Oral Administration ◽  
Rat Brain ◽  
Sodium Fluoride ◽  
Oxidative Stress Markers ◽  
Stress Markers ◽  
The Brain

This study reports the ameliorative role of curcumin against sodium fluoride (NaF) induced oxidative stress in the brain of rats. The rats were divided into control, NaF (20 mg/kg), NaF+Curcumin (20mg/kg) and Curcumin (20mg/kg) groups respectively and treated at everyday interval for 60 consecutive days. Oxidative stress markers in the brain were measured at 60th day. NaF treatment significantly increased LPO content, but decreased the level of GSH and activities of SOD, GPx, and CAT the brain of rats in comparison to the control rats. Oral administration of curcumin to fluoride exposed rats significantly reversed the content of lipid peroxidation, as well as enhanced the level of GSH and SOD, GPx and CAT activities to normal compared to NaF exposed rats. Thus, curcumin showed the potential to prevent sodium fluoride induced oxidative damage in the brain of rats and curcumin may be useful agents against neurodegeneration in the brain.

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