scholarly journals Biochemical Markers of Excitability in Human Neocortex

1991 ◽  
Vol 18 (S4) ◽  
pp. 640-644 ◽  
Author(s):  
A.L. Sherwin ◽  
O. Vernet ◽  
F. Dubeau ◽  
A. Olivier
Keyword(s):  
Amino Acids ◽  
Tyrosine Hydroxylase ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Biochemical Markers ◽  
Excitatory Amino Acids ◽  
Inhibitory Neurotransmitters ◽  
Catecholamine Biosynthesis ◽  
Interictal Spike ◽  
Inhibitory Mechanisms

ABSTRACT:We measured biochemical markers of excitability in brain excised for neurosurgical therapy of epilepsy. Intraoperative electrocorticography was used to identify and compare samples from regions of persistent interictal spike discharges and areas of the cerebral convexity which were free of interictal piking. We found that interictal spiking was associated with elevated tissue levels of the excitatory amino acids glutamic acid (26%, p < 0.001) and aspartic acid (25%, p < 0.05). There was also a significant increase in the activity of the enzymes glutamic acid dehydrogenase (20%, p < 0.01) and aspartate acid aminotransferase (18%, p < 0.01) which are involved in their formation. There was no change in the levels of the inhibitory neurotransmitters GABA or taurine. We also found a significant increase in the activity of tyrosine hydroxylase (52%, p < 0.001), the rate controlling enzyme in catecholamine biosynthesis. There was a reduction in the density (Bmax) of cortical alpha-1 adrenoceptors (26%, p < 0.01) and a concommitant diminution of receptor coupled phosphatidylinositide metabolism (21%, p < 0.01). This blunting of inhibitory noradrenergic transmembrane signaling may contribute to a relative imbalance between excitatory and inhibitory mechanisms in epileptogenic neocortex.

Neuronal depressant effects of diethylester derivatives of excitatory amino acids

1977 ◽  
Vol 55 (6) ◽  
pp. 1387-1390 ◽  
Author(s):  
J. F. MacDonald ◽  
A. Nistri ◽  
A. L. Padjen
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Firing Rate ◽  
Aspartic Acid ◽  
Excitatory Amino Acids ◽  
Neuronal Firing ◽  
Field Stimulation ◽  
Spinal Interneurones ◽  
Depressant Action ◽  
Derivatives Of

The effect of iontophoretically applied kainic acid diethylester (KDEE) on the firing rate of feline spinal interneurones was investigated and compared with the action of glutamic acid diethylester (GDEE) and aspartic acid diethylester (ADEE). All these esters reversibly reduced spontaneous neuronal firing and increased spike height, KDEE being the most active of this group. KDEE decreased responses to glutamate, acetylcholine, and peripheral field stimulation, showing that its depressant action is not due to a selective antagonism of an excitatory putative transmitter.

scholarly journals Utilization in vivo of glucose and volatile fatty acids by sheep brain for the synthesis of acidic amino acids

1966 ◽  
Vol 101 (3) ◽  
pp. 591-597 ◽  
Author(s):  
R M O'Neal ◽  
R E Koeppe ◽  
E I Williams
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Specific Activity ◽  
Tricarboxylic Acid Cycle ◽  
Sheep Brain ◽  
The Brain

1. Free glutamic acid, aspartic acid, glutamic acid from glutamine and, in some instances, the glutamic acid from glutathione and the aspartic acid from N-acetyl-aspartic acid were isolated from the brains of sheep and assayed for radioactivity after intravenous injection of [2-(14)C]glucose, [1-(14)C]acetate, [1-(14)C]butyrate or [2-(14)C]propionate. These brain components were also isolated and analysed from rats that had been given [2-(14)C]propionate. The results indicate that, as in rat brain, glucose is by far the best precursor of the free amino acids of sheep brain. 2. Degradation of the glutamate of brain yielded labelling patterns consistent with the proposal that the major route of pyruvate metabolism in brain is via acetyl-CoA, and that the short-chain fatty acids enter the brain without prior metabolism by other tissue and are metabolized in brain via the tricarboxylic acid cycle. 3. When labelled glucose was used as a precursor, glutamate always had a higher specific activity than glutamine; when labelled fatty acids were used, the reverse was true. These findings add support and complexity to the concept of the metabolic; compartmentation' of the free amino acids of brain. 4. The results from experiments with labelled propionate strongly suggest that brain metabolizes propionate via succinate and that this metabolic route may be a limited but important source of dicarboxylic acids in the brain.

scholarly journals The Content of Non-essential Amino Acids in the Grains of Winter and Spring Varieties of Oats (Avena sativa L.) under the Conditions of Central Southern Bulgaria

2013 ◽  
Vol 14 (1) ◽  
pp. 105
Author(s):  
T. Georgieva ◽  
P. Zorovski
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
G Protein ◽  
Aspartic Acid ◽  
Avena Sativa ◽  
Essential Amino Acids

The purpose of this survey is to study the content of non-essential amino acids in four winter (Dunav 1, Ruse 8, Resor 1, Line M-K) and five spring (Obraztsov chiflik 4, Mina, HiFi, Novosadski golozarnest and Prista 2) cultivars of oats grown in Central Southern Bulgaria within the period from 2007 to 2009. The tested cultivars have different contents of non-essential amino acids. Dunav 1 has the highest quantity of glicine (5.12 g/100 g protein) of all the winter cultivars, Ruse 8 has the highest quantity of alanine (5.69 g/100 g protein) and Resor 1 – the highest quantity of arginine (6.14 g/100 g protein). Generally speaking, the spring cultivars have a larger quantity of glutamic acid (from 25.86 to 26.07 g/100 g protein) and proline (from 6.15 to 8.21 g/100 g protein) but a smaller quantity of glycine (from 4.68 to 4.99 g/100 g protein) compared to the winter cultivars. The naked cultivar Mina has the highest quantity of cystine (2.14 g/100 g protein), cultivar Prista 2 has the highest quantity of proline (8.21 g/100 g protein) and glutamic acid (26.07 g/100g protein) and HiFi ranks first in terms of aspartic acid (9.05 g/100 g protein), serine (5.02 g/100 g protein) and tyrosine (2.09 g/100 g protein). In the study we have also established certain relations between non-essential amino acids.

USE OF GLUTAMIC ACID-U-C14 TO DETERMINE NUTRITIONALLY ESSENTIAL AMINO ACIDS FOR LARVAE OF THE BLOW FLY, PHORMIA REGINA

1960 ◽  
Vol 38 (11) ◽  
pp. 1229-1234 ◽  
Author(s):  
R. Kasting ◽  
A. J. McGinnis
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Essential Amino Acids ◽  
Phormia Regina ◽  
Blow Fly ◽  
Isoleucine Leucine ◽  
Low Level ◽  
Third Instar Larvae

The production of C14O2 by third-instar larvae of the blow fly, Phormia regina Meig., after it was injected with glutamic acid-U-C14, indicates that this substrate was metabolized under these conditions. However, the nutritionally essential amino acids lysine, phenylalanine, valine, isoleucine, leucine, and threonine, isolated from the injected larvae, contained little radioactivity. A low level of radioactivity in arginine, histidine, and methionine suggests that they were slowly synthesized. The nutritionally non-essential amino acids alanine, serine, aspartic acid, and proline contained large quantities of radioactivity; tyrosine and glycine were exceptions. These results, in agreement with earlier work that used glucose-U-C14, show that radioactivity data are useful for determining certain of the nutritionally essential amino acids.

scholarly journals Tracer studies on the biosynthesis of amino acids from lactate by Peptostreptococcus elsdenii

1967 ◽  
Vol 105 (1) ◽  
pp. 299-310 ◽  
Author(s):  
H. J. Somerville ◽  
J. L. Peel
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Tricarboxylic Acid Cycle ◽  
Carbon Chain ◽  
Tricarboxylic Acid ◽  
Diaminopimelic Acid ◽  
Reaction Sequence ◽  
Tracer Studies ◽  
Cell Fractions

Peptostreptococcus elsdenii, a strict anaerobe from the rumen, was grown on a medium containing yeast extract and [1−14C]- or [2−14C]-lactate. Radioisotope from lactate was found in all cell fractions, but mainly in the protein. The label in the protein fraction was largely confined to a few amino acids: alanine, serine, aspartic acid, glutamic acid and diaminopimelic acid. The alanine, serine, aspartic acid and glutamic acid were separated, purified and degraded to establish the distribution of 14C from lactate within the amino acid molecules. The labelling patterns in alanine and serine suggested their formation from lactate without cleavage of the carbon chain. The pattern in aspartic acid suggested formation by condensation of a C3 unit derived directly from lactate with a C1 unit, probably carbon dioxide. The distribution in glutamic acid was consistent with two possible pathways of formation: (a) by the reactions of the tricarboxylic acid cycle leading from oxaloacetate to 2-oxoglutarate, followed by transamination; (b) by a pathway involving the reaction sequence 2 acetyl-CoA→crotonyl-CoA→glutaconate→glutamate.

The influence of diet on the nitrogenous components passing to the duodenum and through the lower ileum of sheep

1966 ◽  
Vol 166 (1002) ◽  
pp. 63-79 ◽  
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Nitrogen Content ◽  
Aspartic Acid ◽  
Total Nitrogen ◽  
Amino Nitrogen ◽  
Terminal Part ◽  
High Nitrogen ◽  
Low Nitrogen ◽  
Lower Ileum

Analyses of the alimentary contents flowing to the duodenum of sheep during 24 h show that when the sheep are consuming a low-nitrogen diet more total nitrogen and amino nitrogen pass to the duodenum than are eaten daily in the food whereas when the sheep are eating high nitrogen diets, less total nitrogen and less amino nitrogen pass to the duodenum. The disparity between the total nitrogen and amino nitrogen content of the diets largely disappeared by the time the alimentary contents reached the terminal part of the ileum. From 64 to 68% of the nitrogen entering the duodenum and 54 to 64% of the nitrogen in the ileal contents was in the form of amino nitrogen. Proportionately more of the amino nitrogen was in solution in the ileal contents than in the duodenal contents. Losses of amino acids in the stomach when a high-nitrogen diet was consumed were especially large for glutamic acid, aspartic acid, proline, arginine and leucine. They were least for cystine and threonine. Gains of amino acids in the stomach when low nitrogen diets were consumed were all substantial except for proline, where a loss was found when hay and flaked maize were given. When these changes are considered as proportions of the quantities eaten then trends are similar for all acids. Changes in the molar proportions of the amino acids present in hydrolysates of the duodenal and ileal contents are discussed together with the significance of these changes in relation to the nutrition of the sheep.

scholarly journals Strecker degradation products of aspartic and glutamic acids and their amides

2013 ◽  
Vol 19 (No. 2) ◽  
pp. 41-45 ◽  
Author(s):  
J. Rössner ◽  
J. Velíšek ◽  
F. Pudil ◽  
J. Davídek
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Aspartic Acid ◽  
Degradation Products ◽  
Dicarboxylic Acids ◽  
Reaction Products ◽  
Degradation Reactions ◽  
Strecker Aldehydes ◽  
Volatile Products ◽  
Acid Acid

Aspartic and glutamic acids, asparagine and glutamine were oxidised with either potassium peroxodisulphate or glyoxal. Nonvolatile products were derivatised and analysed by GC/FID and GC/MS. Volatile reaction products were isolated and analysed by the same methods. It was found that the degradation reactions of amino acids are complex. Amino acids are principally degraded via the corresponding a-keto acids to Strecker aldehydes (aspartic acid to oxalacetic and 3-oxopropionic acids and glutamic acid to a-ketoglutaric and 4-oxobutyric acids), which are unstable and decomposed by decarboxylation to the corresponding aldehydes. Aspartic acid also eliminates ammonia and yields fumaric acid whereas glutamic acid gives rise to an imine, pyroglutamic acid. A recombination of free radicals leads to dicarboxylic acids (succinic acid from aspartic acid, succinic, glutaric and adipic acids from glutamic acid). The major volatile products (besides the aldehydes) are lower carboxylic acids (acetic acid from aspartic acid and propionic acid acid from glutamic acid) that can at least partly arise by radical reactions. In both quality and quantity terms, a higher amount of degradation products arises by oxidation of amino acids by peroxodisulphate.

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