Release of 3H-γ-Aminobutyric Acid from the Brain during Synaptic Inhibition

Nature ◽  
1969 ◽  
Vol 224 (5220) ◽  
pp. 663-666 ◽  
Author(s):  
J. F. MITCHELL ◽  
VASANTA SRINIVASAN
1986 ◽  
Vol 71 (6) ◽  
pp. 749-753 ◽  
Author(s):  
J. E. Maddison ◽  
D. Yau ◽  
P. Stewart ◽  
G. C. Farrell

1. Cerebrospinal fluid (CSF) γ-aminobutyric acid (GABA) levels were measured in a dog model of spontaneous chronic portosystemic encephalopathy. 2. Dogs with congenital portacaval shunts (intra- or extra-hepatic) develop neurological features of abnormal psychomotor behaviour and depressed consciousness that are consistent with the symptoms of chronic portosystemic encephalopathy in humans. In the five dogs studied, plasma ammonia was elevated, as was CSF tryptophan, both usual biochemical abnormalities in portosystemic encephalopathy. 3. CSF levels of GABA in five dogs with portosystemic encephalopathy (100 ± 13 pmol/ml) were not significantly different from those in five control dogs (96 ± 14 pmol/ml). CSF levels of GABA were not altered after ammonia infusion. 4. If enhanced GABA-ergic neurotransmission, due to influx of gut-derived GABA into the brain, is responsible for the pathophysiology of chronic portosystemic encephalopathy in this model, it is not reflected by increased levels of GABA in CSF.


Author(s):  
Yehezkel Ben-Ari ◽  
Enrico Cherubini ◽  
Massimo Avoli

After over seven decades of neuroscience research, it is now well established that γ-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain. In this paper dedicated to Krešimir Krnjević (1927–2021), a pioneer and leader in neuroscience, we briefly highlight the fundamental contributions he made in identifying GABA as an inhibitory neurotransmitter in the brain and our personal interactions with him. Of note, between 1972 and 1978 Dr. Krnjević was a highly reputed Chief Editor of the Canadian Journal of Physiology and Pharmacology.


2009 ◽  
Vol 55 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Kazuyo TUJIOKA ◽  
Miho OHSUMI ◽  
Kenji HORIE ◽  
Mujo KIM ◽  
Kazutoshi HAYASE ◽  
...  

1979 ◽  
Vol 57 (7) ◽  
pp. 688-694 ◽  
Author(s):  
A. K. Singh ◽  
E. W. Banister

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.


2015 ◽  
Vol 96 (5) ◽  
pp. 806-810
Author(s):  
R V Deev ◽  
Yu M Shatrova ◽  
A I Sinitskiy ◽  
N S Molchanova ◽  
A K Yunusova ◽  
...  

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.


1969 ◽  
Vol 47 (10) ◽  
pp. 994-997 ◽  
Author(s):  
J. D. Wood ◽  
W. J. Watson

In rats and guinea pigs exposed to hyperoxic conditions, the levels of both bound and free γ-aminobutyric acid in the brain were decreased, and under hypoxic conditions both were increased. A small but significant change in the proportion of γ-aminobutyric acid in the bound form was observed in the exposed animals. The significance of the findings is discussed.


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