Blood-brain amino acid transport and content during anoxia and reoxygenation.

1977 ◽  
Vol 233 (4) ◽  
pp. E326
Author(s):  
L R Drewes ◽  
W P Conway ◽  
D D Gilboe

The isolated dog brain preparation was used to investigate the dynamics of cerebral amino acid metabolism during perfusion with anoxic blood (PO2 less than 10 mmHg). Significant uptake of histidine and lysine, as determined by arteriovenous (A-V) differences in whole blood samples, was observed during 30 min of cerebral anoxia. The A-V differences determined from plasma samples indicated that uptake of histidine and efflux of glutamic acid and proline had occurred. Nitrogen balance in the preparation appeared to be maintained. Thirty minutes of anoxic perfusion resulted in increased tissue concentrations of five essential amino acids (methionine, histidine, leucine, lysine, and valine) and a decreased tissue level of the essential amino acids threonine and phenylalanine. Taurine, gamma-aminobutyric acid, alanine, glycerophosphoethanolamine and phosphoethanolamine also increased, whereas the aspartic acid concentration declined. When aerobic perfusion was resumed, the total pool of essential amino acids continued to increase and was nearly twice normal after 120 min of reperfusion. The combined concentration of asparagine and glutamine, serine, alpha-aminobutyric acid, and cystathionine also increased during postanoxic perfusion. Only taurine and phenylalanine concentrations returned toward normal.

1964 ◽  
Vol 11 (01) ◽  
pp. 064-074 ◽  
Author(s):  
Robert H Wagner ◽  
William D McLester ◽  
Marion Smith ◽  
K. M Brinkhous

Summary1. The use of several amino acids, glycine, alpha-aminobutyric acid, alanine, beta-alanine, and gamma-aminobutyric acid, as plasma protein precipitants is described.2. A specific procedure is detailed for the preparation of canine antihemophilic factor (AHF, Factor VIII) in which glycine, beta-alanine, and gammaaminobutyric acid serve as the protein precipitants.3. Preliminary results are reported for the precipitation of bovine and human AHF with amino acids.


2020 ◽  
Vol 93 ◽  
pp. 102958
Author(s):  
Boonyote Kamjijam ◽  
Hanna Bednarz ◽  
Prisana Suwannaporn ◽  
Kriskamol Na Jom ◽  
Karsten Niehaus

1962 ◽  
Vol 202 (4) ◽  
pp. 695-698 ◽  
Author(s):  
S. A. Kaplan ◽  
C. S. Nagareda Shimizu

Concentrations of the following Ninhydrin-reacting substances (NRS) were determined in the unhydrolyzed protein-free fraction of mouse liver by column chromatography: phosphoethanolamine, taurine, urea, aspartic acid, threonine, serine, glutamine, proline, glutamic acid, glycine, alanine, valine, cystine, methionine, isoleucine, leucine, tyrosine, phenylalanine, ß-alanine, ß-aminoisobutyric acid, α-aminobutyric acid, ornithine, ethanolamine, lysine, histidine, and arginine. The NRS present in highest concentration was taurine. Adrenalectomy, fasting for 24 hr, and cortisol administration had little effect on the sum of NRS or individual amino acids. Administration of cortisol did, however, decrease the concentration of amino acids in fasted adrenalectomized animals but increased their concentration in nonfasted adrenalectomized animals. Since the concentration of amino acids was lowered or raised under circumstances known to increase protein synthesis, it is concluded that increased protein synthesis promoted by cortisol is independent of the total pool of amino acids in liver.


1996 ◽  
Vol 85 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Ken Nakashima ◽  
Michael M. Todd

Background Hypothermia and anesthetics may protect the brain during ischemia by blocking the release of excitatory amino acids. The effects of hypothermia (28 degrees C), pentobarbital, and isoflurane on postischemic excitatory amino acid concentrations were compared. Methods Rats were anesthetized with 0.8% halothane/50% N2O, vascular catheters were placed, and a glass microelectrode and microdialysis cannula were inserted into the cerebral cortex. Experimental groups were: (1) control, pericranial, t = 38 degrees C; (2) hypothermia, t = 28 degrees C; (3) pentobarbital, t = 38 degrees C; and (4) isoflurane, t = 38 degrees C. Halothane/N2O was continued in groups 1 and 2, whereas a deep burst-suppression or isoelectric electroencephalogram was achieved with the test drugs in groups 3 and 4. Cerebral metabolic rates were similar in groups 2, 3, and 4. After a baseline dialysis sample was collected, animals were killed with potassium chloride. The time to terminal depolarization was recorded, after which three consecutive 10-min dialysate samples were collected. Glutamate, aspartate, gamma-aminobutyric acid, and glycine concentrations were measured using high-performance liquid chromatography. Results Times to terminal depolarization were shorter in both pentobarbital and isoflurane groups than with hypothermia (103 +/- 15 and 127 +/- 10 vs. 195 +/- 20 s respectively, mean +/- SD). However, times to terminal depolarization in all three groups were longer than in control subjects (control = 70 +/- 9s). Postdepolarization concentrations of all compounds were lower in hypothermic animals (vs. normothermic control animals), but no reductions in glutamate, aspartate, or glycine concentrations were noted in pentobarbital or isoflurane groups. gamma-Aminobutyric acid concentrations were reduced by both anesthetics, but not to the same degree as with hypothermia. Conclusions Pentobarbital and isoflurane prolonged the time to terminal depolarization, but did not influence the rate at which the extracellular concentrations of glutamate, aspartate, or glycine increased. By contrast, hypothermia reduced the release of all excitatory amino acids. These differences may explain the greater protective efficacy of hypothermia in the face of cerebral ischemia.


1978 ◽  
Vol 44 (3) ◽  
pp. 333-339 ◽  
Author(s):  
J. Weyne ◽  
F. Van Leuven ◽  
H. Kazemi ◽  
I. Leusen

Glutamic, aspartic, and gamma-aminobutyric acid (GABA), glutamine, and ammonium were measured in the brains of unanesthetized normocapnic and hypercapnic (10% CO2; 5 min to 3 wk) rats. Hypercapnia increased glutamine and GABA and decreased glutamic and aspartic acids. Changes occurred within 1 h and were maintained during the observation period of 3 wk. On return to normocapnia amino acid concentrations were almost normal after 1 h. Based on the time course it is concluded that intracerebral hypercapnia is more likely the stimulus for change than acidosis. Ammonium content was unchanged for at least 1 h after the onset of hypercapnia but increased thereafter. Experiments in which glutamine synthesis by brain was impeded by inhibiting the enzyme glutamine synthetase favor the hypothesis that the rise of ammonium content in hypercapnia is initially not seen because of increased glutamine synthesis. The changes observed may have a role in metabolic pH homeostasis of brain tissue and may also be relevant to the modified brain excitability in hypercapnia.


2016 ◽  
Vol 5 (10) ◽  
pp. 4972
Author(s):  
Lata Birlangi

The date palm (Phoenix dactylifera L.) is one of mankind’s oldest cultivated plants. The fruit of the date palm is an important crop of the hot arid and semi-arid regions of the world. It has always played a genuine economic and social part in the lives of the people of these areas. The present objective in examining the amino acid content of different varieties of date palm fruits from Middle-East region; is to determine whether its protein could effectively supplement the nutritional value and it is also aimed in finding which variety is rich in number of amino acids. The phytochemical screening revealed the presence of eight essential amino acids and five non-essential amino acids in the date fruits. Among all the date fruit varieties taken as samples for the study, Dabbas cultivar of United Arab Emirates found to exhibit eight types of amino acids which includes five as non-essential ones. Total of thirteen amino acids were detected in the seven date cultivars. Determination of amino acid can serve as a guide to the possible nutritional value.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sonia Yun Liu ◽  
Shemil P. Macelline ◽  
Peter V. Chrystal ◽  
Peter H. Selle

AbstractThe prime purpose of this review is to explore the pathways whereby progress towards reduced-crude protein (CP) diets and sustainable chicken-meat production may be best achieved. Reduced-CP broiler diets have the potential to attenuate environmental pollution from nitrogen and ammonia emissions; moreover, they have the capacity to diminish the global chicken-meat industry’s dependence on soybean meal to tangible extents. The variable impacts of reduced-CP broiler diets on apparent amino acid digestibility coefficients are addressed. The more accurate identification of amino acid requirements for broiler chickens offered reduced-CP diets is essential as this would diminish amino acid imbalances and the deamination of surplus amino acids. Deamination of amino acids increases the synthesis and excretion of uric acid for which there is a requirement for glycine, this emphasises the value of so-called “non-essential” amino acids. Starch digestive dynamics and their possible impact of glucose on pancreatic secretions of insulin are discussed, although the functions of insulin in avian species require clarification. Maize is probably a superior feed grain to wheat as the basis of reduced-CP diets; if so, the identification of the underlying reasons for this difference should be instructive. Moderating increases in starch concentrations and condensing dietary starch:protein ratios in reduced-CP diets may prove to be advantageous as expanding ratios appear to be aligned to inferior broiler performance. Threonine is specifically examined because elevated free threonine plasma concentrations in birds offered reduced-CP diets may be indicative of compromised performance. If progress in these directions can be realised, then the prospects of reduced-CP diets contributing to sustainable chicken-meat production are promising.


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