GAMMA-AMINOBUTYRIC ACID LEVELS IN THE BRAIN OF RATS EXPOSED TO OXYGEN AT HIGH PRESSURES

1963 ◽  
Vol 41 (1) ◽  
pp. 1907-1913 ◽  
Author(s):  
J. D. Wood ◽  
W. J. Watson
Keyword(s):  
High Pressure ◽  
Recovery Time ◽  
High Pressures ◽  
No Reduction ◽  
Ambient Pressure ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Gaba Concentration ◽  
Short Period ◽  
The Brain

Rats were exposed to 100% oxygen at a pressure of 6 atmospheres absolute for 33 minutes. The surviving animals were assigned to one of three groups: (a) animals suffering severe convulsions during exposure, (b) animals suffering mild convulsions during exposure, (c) animals in which no convulsions were observed during exposure. The concentration of gamma-aminobutyric acid (GABA) in the brains of rats in all groups was lower than in unexposed rats, reductions of 35%, 27%, and 19% in GABA concentration being observed in groups (a), (b), and (c) respectively. Only a few minutes' exposure to oxygen at high pressure was necessary to cause a significant decrease in GABA concentration. Exposure either to air at high pressure or to 100% oxygen at ambient pressure produced no reduction in GABA levels. Although the GABA concentration in the brain increased markedly within 1 hour after the end of the 33-minute exposure to oxygen at 6 atm pressure it was still somewhat below the levels found in unexposed animals. No significant change in GABA levels was observed during a further 2 hours of recovery time. In the case of rats exposed for only a short period of time, however, a complete return to normal was observed within the first hour. The levels of glutamic acid, aspartic acid, and total α-amino acids in the brain were not altered by exposure to oxygen at high pressure.

GAMMA-AMINOBUTYRIC ACID LEVELS IN THE BRAIN OF RATS EXPOSED TO OXYGEN AT HIGH PRESSURES

1963 ◽  
Vol 41 (9) ◽  
pp. 1907-1913 ◽  
Author(s):  
J. D. Wood ◽  
W. J. Watson
Keyword(s):  
High Pressure ◽  
Recovery Time ◽  
High Pressures ◽  
No Reduction ◽  
Ambient Pressure ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Gaba Concentration ◽  
Short Period ◽  
The Brain

Rats were exposed to 100% oxygen at a pressure of 6 atmospheres absolute for 33 minutes. The surviving animals were assigned to one of three groups: (a) animals suffering severe convulsions during exposure, (b) animals suffering mild convulsions during exposure, (c) animals in which no convulsions were observed during exposure. The concentration of gamma-aminobutyric acid (GABA) in the brains of rats in all groups was lower than in unexposed rats, reductions of 35%, 27%, and 19% in GABA concentration being observed in groups (a), (b), and (c) respectively. Only a few minutes' exposure to oxygen at high pressure was necessary to cause a significant decrease in GABA concentration. Exposure either to air at high pressure or to 100% oxygen at ambient pressure produced no reduction in GABA levels. Although the GABA concentration in the brain increased markedly within 1 hour after the end of the 33-minute exposure to oxygen at 6 atm pressure it was still somewhat below the levels found in unexposed animals. No significant change in GABA levels was observed during a further 2 hours of recovery time. In the case of rats exposed for only a short period of time, however, a complete return to normal was observed within the first hour. The levels of glutamic acid, aspartic acid, and total α-amino acids in the brain were not altered by exposure to oxygen at high pressure.

scholarly journals Putrescine, a source of γ-aminobutyric acid in the adrenal gland of the rat

1988 ◽  
Vol 251 (2) ◽  
pp. 559-562 ◽  
Author(s):  
P C Caron ◽  
L J Cote ◽  
L T Kremzner
Keyword(s):  
Adrenal Gland ◽  
Diamine Oxidase ◽  
Cell Metabolism ◽  
Turnover Time ◽  
Oxidase Inhibitor ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Gaba Concentration ◽  
The Brain

Putrescine is the major source of gamma-aminobutyric acid (GABA) in the rat adrenal gland. Diamine oxidase, and not monoamine oxidase, is essential for GABA formation from putrescine in the adrenal gland. Aminoguanidine, a diamine oxidase inhibitor, decreases the GABA concentration in the adrenal gland by more than 70% after 4 h, and almost to zero in 24 h. Studies using [14C]putrescine confirm that [14C]GABA is the major metabolite of putrescine in the adrenal gland. Inhibition of GABA transaminase by amino-oxyacetic acid does not change the GABA concentration in the adrenal gland, as compared with the brain, where the GABA concentration rises. With aminoguanidine, the turnover time of GABA originating from putrescine in the adrenal gland is 5.6 h, reflecting a slower rate of GABA metabolism compared with the brain. Since GABA in the adrenal gland is almost exclusively derived from putrescine, the role of GABA may relate to the role of putrescine as a growth factor and regulator of cell metabolism.

Effect of adrenalectomy on convulsions induced by high-pressure oxygen

1979 ◽  
Vol 57 (7) ◽  
pp. 688-694 ◽  
Author(s):  
A. K. Singh ◽  
E. W. Banister
Keyword(s):  
High Pressure ◽  
Acid Level ◽  
Amino Acid Level ◽  
Aminobutyric Acid ◽  
Pressure Oxygen ◽  
Significant Difference ◽  
High Pressure Oxygen ◽  
Brain Gaba ◽  
The Brain ◽  
Adrenalectomized Rats

Adrenalectomized rats exposed to high pressure oxygen (OHP) until convulsion convulse much later than sham-operated or normal rats. No significant changes in the concentration of noradrenaline (NA) and total catecholamines (TC) in the brain were noted in sham-operated or adrenalectomized rats resulting from sham or real surgery and no change occurred in these variables in normal sham-operated or adrenalectomized animals after OHP leading to convulsion. Brain adrenaline (A) concentration, however, decreased significantly in all three groups following OHP-induced convulsions. Activity of catecholamine O-methyltransferase (COMT) decreased significantly only in adrenalectomized rats. Brain γ-aminobutyric acid (GABA), glutamate, and other amino acid level remained unchanged after adrenalectomy whereas the concentration of ammonia decreased significantly when normal rats were adrenalectomized. After OHP-induced convulsions, the concentrations of brain GABA and glutamate decreased and ammonia and glutamine plus asparagine increased significantly in normal, sham-operated, and adrenalectomized rats. In the blood no significant difference was noted in the concentration of the catecholamines, ammonia, and amino acids either in normal or sham-operated rats. In adrenalectomized rats, the blood A and NA concentrations decreased significantly and tyrosine increased significantly. The concentration of NA, ammonia, and glutamine plus asparagine in rats from all three groups increased after OHP-induced convulsions, whereas the concentration of glutamate decreased significantly. Since the concentration of A increased significantly after convulsions in normal and sham-operated rats but did not change in adrenalectomized rats, it might be proposed that adrenalectomy protects against OHP-induced convulsions by reducing the circulating concentration of A and ammonia.However, these are not the only factors involved in the protection since the sham-operated rats also convulsed much later than normal rats but had similar ammonia and A concentrations to normal animals.

scholarly journals Levels of biogenic amines in the brain of rats at experimental post-traumatic stress disorder development

2015 ◽  
Vol 96 (5) ◽  
pp. 806-810
Author(s):  
R V Deev ◽  
Yu M Shatrova ◽  
A I Sinitskiy ◽  
N S Molchanova ◽  
A K Yunusova ◽  
...  
Keyword(s):  
Post Traumatic Stress Disorder ◽  
Traumatic Stress ◽  
Acid Level ◽  
Stress Disorder ◽  
Aminobutyric Acid ◽  
Behavioral Activity ◽  
Gamma Aminobutyric Acid ◽  
Post Traumatic Stress ◽  
Post Traumatic ◽  
The Brain

Aim. To study the changes in levels of biogenic amines-neurotransmitters in the brain at experimental post-traumatic stress disorder development in rats. Methods. Post-traumatic stress disorder was modeled by keeping 48 outbred male rats in under constant and inescapable strong unconditioned stimulus. The control group included 16 intact animals, not exposed to stress influences. The levels of 3,4-dihydroxyphenylalanine, dopamine, norepinephrine, epinephrine and gamma-aminobutyric acid were determined by fluorometric methods. Behavioral activity of animals was evaluated on the day 3, 7, 10 and 14 by «open field» and «elevated plus maze» actinographs. Results. When comparing the concentrations of studied neurotransmitters in the brain of control animals with experimental groups, reflecting the development of post-traumatic stress disorder at the time, adrenaline and 3,4-dihydroxyphenylalanine levels were increased on the third day, level of norepinephrine was reduced on the seventh day, 3,4-dihydroxyphenylalanine, dopamine, norepinephrine levels were elevaled, gamma-aminobutyric acid level was reduced on the tenth day, gamma-aminobutyric acid level was increased on the fourteenth day after the stress. Conclusion. According to the results of the correlation analysis, the largest contribution to the development of behavioral disorders are made by altered brain level of gamma-aminobutyric acid at the time of post-traumatic stress disorder formation (tenth and fourteenth day). At the earlier stages (third and seventh day), the relationship of rats behavioral activity and altered 3,4-dihydroxyphenylalanine and norepinephrine brain levels was shown.

scholarly journals Pressure-Dependent Clustering in Ionic-Liquid-Poly (Vinylidene Fluoride) Mixtures: An Infrared Spectroscopic Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2099
Author(s):  
Teng-Hui Wang ◽  
Wei-Xiang Wang ◽  
Hai-Chou Chang
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Vinylidene Fluoride ◽  
Ambient Pressure ◽  
Infrared Spectroscopic Study ◽  
Research Attention ◽  
Nanoscale Structures ◽  
Local Structures ◽  
Poly Vinylidene Fluoride ◽  
Hydrogen Bonded

The nanostructures of ionic liquids (ILs) have been the focus of considerable research attention in recent years. Nevertheless, the nanoscale structures of ILs in the presence of polymers have not been described in detail at present. In this study, nanostructures of ILs disturbed by poly(vinylidene fluoride) (PVdF) were investigated via high-pressure infrared spectra. For 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([HEMIm][TFSI])-PVdF mixtures, non-monotonic frequency shifts of the C4,5-H vibrations upon dilution were observed under ambient pressure. The experimental results suggest the presence of microheterogeneity in the [HEMIm][TFSI] systems. Upon compression, PVdF further influenced the local structure of C4,5–H via pressure-enhanced IL–PVdF interactions; however, the local structures of C2–H and hydrogen-bonded O–H were not affected by PVdF under high pressures. For choline [TFSI]–PVdF mixtures, PVdF may disturb the local structures of hydrogen-bonded O–H. In the absence of the C4,5–H⋯anion and C2–H⋯anion in choline [TFSI]–PVdF mixtures, the O–H group becomes a favorable moiety for pressure-enhanced IL–PVdF interactions. Our results indicate the potential of high-pressure application for designing pressure-dependent electronic switches based on the possible changes in the microheterogeneity and electrical conductivity in IL-PVdF systems under various pressures.

The Effects of Agonists of Ionotropic GABAAand Metabotropic GABABReceptors on Learning

2009 ◽  
Vol 12 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Evgeniya A. Zyablitseva ◽  
Nikolay S. Kositsyn ◽  
Galina I. Shul'gina
Keyword(s):  
Affect Regulation ◽  
Gaba Receptors ◽  
Conditioned Inhibition ◽  
Early Stage ◽  
Dominant Role ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Internal Inhibition ◽  
Selective Agonist ◽  
The Brain

The research described here investigates the role played by inhibitory processes in the discriminations made by the nervous system of humans and animals between familiar and unfamiliar and significant and nonsignificant events. This research compared the effects of two inhibitory mediators of gamma-aminobutyric acid (GABA): 1) phenibut, a nonselective agonist of ionotropic GABAAand metabotropic GABABreceptors and 2) gaboxadol a selective agonist of ionotropic GABAAreceptors on the process of developing active defensive and inhibitory conditioned reflexes in alert non-immobilized rabbits. It was found that phenibut, but not gaboxadol, accelerates the development of defensive reflexes at an early stage of conditioning. Both phenibut and gaboxadol facilitate the development of conditioned inhibition, but the effect of gaboxadol occurs at later stages of conditioning and is less stable than that of phenibut. The earlier and more stable effects of phenibut, as compared to gaboxadol, on storage in memory of the inhibitory significance of a stimulus may occur because GABABreceptors play the dominant role in the development of internal inhibition during an early stage of conditioning. On the other hand this may occur because the participation of both GABAAand GABABreceptors are essential to the process. We discuss the polyfunctionality of GABA receptors as a function of their structure and the positions of the relevant neurons in the brain as this factor can affect regulation of various types of psychological processes.

PRESSURE-INDUCED ELECTRONIC PHASE TRANSITIONS AND SUPERCONDUCTIVITY IN TITANIUM

2009 ◽  
Vol 23 (05) ◽  
pp. 723-741 ◽  
Author(s):  
K. IYAKUTTI ◽  
C. NIRMALA LOUIS ◽  
S. ANURATHA ◽  
S. MAHALAKSHMI
Keyword(s):  
High Pressure ◽  
Band Structure ◽  
Fermi Surface ◽  
High Pressures ◽  
Ambient Pressure ◽  
Structural Phase ◽  
Normal Pressure ◽  
Orbital Method ◽  
Superconducting Transition ◽  
Electronic Band

The electronic band structure, density of states, structural phase transition, superconducting transition and Fermi surface cross section of titanium ( Ti ) under normal and high pressures are reported. The high pressure band structure exhibits significant deviations from the normal pressure band structure due to s → d transition. On the basis of band structure and total energy results obtained using tight-binding linear muffin-tin orbital method (TB LMTO), we predict a phase transformation sequence of α( hcp ) → ω (hexagonal) → γ (distorted hcp) → β (bcc) in titanium under pressure. From our analysis, we predict a δ (distorted bcc) phase which is not stable at any high pressures. At ambient pressure, the superconducting transition occurs at 0.354 K. When the pressure is increased, it is predicted that, Tc increases at a rate of 3.123 K/Mbar in hcp–Ti . On further increase of pressure, Tc begins to decrease at a rate of 1.464 K/Mbar. The highest value of Tc(P) estimated is 5.043 K for hcp–Ti , 4.538 K for ω– Ti and 4.85 K for bcc – Ti . From this, it is inferred that the maximum value of Tc(P) is rather insensitive to the crystal structure of Ti . The nonlinearities in Tc(P) is explained by considering the destruction and creation of new parts of Fermi surface at high pressure. At normal pressure, the hardness of Ti is in the following order: ω- Ti > hcp - Ti > bcc- Ti > γ- Ti .

scholarly journals Metabolomic changes in animal models of depression: a systematic analysis

2021 ◽  
Author(s):  
Juncai Pu ◽  
Yiyun Liu ◽  
Siwen Gui ◽  
Lu Tian ◽  
Yue Yu ◽  
...  
Keyword(s):  
Animal Models ◽  
Large Scale ◽  
Hippuric Acid ◽  
Aminobutyric Acid ◽  
Blood Metabolites ◽  
Pimelic Acid ◽  
Gamma Aminobutyric Acid ◽  
Systematic Analysis ◽  
Animal Models Of Depression ◽  
The Brain

AbstractExtensive research has been carried out on the metabolomic changes in animal models of depression; however, there is no general agreement about which metabolites exhibit constant changes. Therefore, the aim of this study was to identify consistently altered metabolites in large-scale metabolomics studies of depression models. We performed vote counting analyses to identify consistently upregulated or downregulated metabolites in the brain, blood, and urine of animal models of depression based on 3743 differential metabolites from 241 animal metabolomics studies. We found that serotonin, dopamine, gamma-aminobutyric acid, norepinephrine, N-acetyl-L-aspartic acid, anandamide, and tryptophan were downregulated in the brain, while kynurenine, myo-inositol, hydroxykynurenine, and the kynurenine to tryptophan ratio were upregulated. Regarding blood metabolites, tryptophan, leucine, tyrosine, valine, trimethylamine N-oxide, proline, oleamide, pyruvic acid, and serotonin were downregulated, while N-acetyl glycoprotein, corticosterone, and glutamine were upregulated. Moreover, citric acid, oxoglutaric acid, proline, tryptophan, creatine, betaine, L-dopa, palmitic acid, and pimelic acid were downregulated, and hippuric acid was upregulated in urine. We also identified consistently altered metabolites in the hippocampus, prefrontal cortex, serum, and plasma. These findings suggested that metabolomic changes in depression models are characterized by decreased neurotransmitter and increased kynurenine metabolite levels in the brain, decreased amino acid and increased corticosterone levels in blood, and imbalanced energy metabolism and microbial metabolites in urine. This study contributes to existing knowledge of metabolomic changes in depression and revealed that the reproducibility of candidate metabolites was inadequate in previous studies.

LEAD-CHALCOGENIDES UNDER PRESSURE: AB-INITIO STUDY

2013 ◽  
Vol 22 ◽  
pp. 612-618 ◽  
Author(s):  
DINESH C. GUPTA ◽  
IDRIS HAMID
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Ab Initio ◽  
Band Gap ◽  
Rock Salt ◽  
High Pressures ◽  
Ambient Pressure ◽  
High Pressure Phase ◽  
Lead Chalcogenides ◽  
Pressure Phase

ab-initio calculations using fully relativistic pseudo-potential have been performed to investigate the high pressure phase transition, elastic and electronic properties of lead-chalcogenides including the less known lead polonium. The calculated ground state parameters, for the rock-salt structure show good agreement with the experimental data. The enthalpy calculations show that these materials undergo a first-order phase transition from rock-salt to CsCl structure at 19.4, 15.5, 11.5 and 7.3 GPa for PbS, PbSe, PbTe and PbPo, respectively. Present calculations successfully predicted the location of the band gap at L-point of Brillouin zone as well as the value of the band gap in every case at ambient pressure. It is observed that unlike other lead-chalcogenides, PbPo is semi-metal at ambient pressure. The pressure variation of the energy gap indicates that these materials metalized under high pressures. For this purpose, the electronic structure of these materials has also been computed in parent as well as in high pressure phase.

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