Selected brain amino acids and ammonium during chronic hypercapnia in conscious rats

1978 ◽  
Vol 44 (3) ◽  
pp. 333-339 ◽  
Author(s):  
J. Weyne ◽  
F. Van Leuven ◽  
H. Kazemi ◽  
I. Leusen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamine Synthetase ◽  
Time Course ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Ph Homeostasis ◽  
Glutamine Synthesis ◽  
Amino Acid Concentrations ◽  
Observation Period

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.

Purification of Antihemophilic Factor (Factor VIII) by Amino Acid Precipitation*

1964 ◽  
Vol 11 (01) ◽  
pp. 064-074 ◽  
Author(s):  
Robert H Wagner ◽  
William D McLester ◽  
Marion Smith ◽  
K. M Brinkhous
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Factor Viii ◽  
Plasma Protein ◽  
Acid Precipitation ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Specific Procedure ◽  
Beta Alanine ◽  
Antihemophilic Factor

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.

Brain amino acid concentrations during diving and acid-base stress in turtles

1985 ◽  
Vol 58 (6) ◽  
pp. 1751-1754 ◽  
Author(s):  
B. M. Hitzig ◽  
M. P. Kneussl ◽  
V. Shih ◽  
R. D. Brandstetter ◽  
H. Kazemi
Keyword(s):  
Amino Acid ◽  
Aminobutyric Acid ◽  
Breath Hold ◽  
Gamma Aminobutyric Acid ◽  
Amino Acid Neurotransmitters ◽  
Acid Base ◽  
Ventilatory Drive ◽  
Amino Acid Concentrations ◽  
Brain Amino Acid

To assess the role of brain amino acid neurotransmitters in the breath hold of diving animals, concentrations of free amino acids present in the brains of turtles immediately after 2 h of apneic diving (at 20 degrees C) were measured. Additionally, the same measurements were performed on four other groups of animals subjected to 2 h of hypercapnia (8% CO2 in air), anoxia (N2 breathing), anoxia plus hypercapnia (8% CO2–92% N2), or air breathing (control). Significant changes in the concentrations of the inhibitory amino acid neurotransmitters known to affect respiration [gamma-aminobutyric acid (GABA) and taurine] were seen. GABA increased significantly in those animals subjected to anoxia, whereas taurine decreased significantly in the diving animals and increased significantly in those subjected to anoxia plus hypercapnia. These results suggest that the attenuated central ventilatory drive during diving in these animals may be related to alterations in brain concentrations of GABA and taurine.

Free Amino Acid Concentrations in Leaves of Sodium-Deficient C4 Plants

1986 ◽  
Vol 13 (3) ◽  
pp. 343 ◽  
Author(s):  
CPL Grof ◽  
M Johnston ◽  
PF Brownell
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Free Amino Acid ◽  
Free Amino ◽  
Aminobutyric Acid ◽  
Amaranthus Tricolor ◽  
Mature Leaves ◽  
C4 Species ◽  
Chloris Gayana ◽  
Amino Acid Concentrations

Consistent changes in the free amino acid concentrations in response to sodium nutrition were observed in mature leaves of the C4 species Amaranthus tricolor and Chloris gayana. The amino acids alanine, γ-aminobutyric acid and glycine were present in greater and aspartate and arginine in lower concentrations in mature leaves of sodium-deficient than in normal plants of both species.

Free amino acid concentrations in needles of Norway spruce and Scots pine trees on different sites in areas with two levels of nitrogen deposition

1990 ◽  
Vol 20 (8) ◽  
pp. 1132-1136 ◽  
Author(s):  
Ann-Britt Edfast ◽  
Torgny Näsholm ◽  
Anders Ericsson
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Nitrogen Deposition ◽  
Free Amino Acids ◽  
Free Amino ◽  
Aminobutyric Acid ◽  
Site Quality ◽  
Southern Sweden ◽  
Amino Acid Concentrations

The effects of nitrogen deposition and site quality on amino acid concentrations in needles of Piceaabies (L.) Karst. and Pinussylvestris L. trees were studied in two areas that represent different levels of nitrogen deposition: one area in southern Sweden and one area in northern Sweden receive, respectively, approximately 20–30 and 3 kg•ha−1•year−1 of nitrogen. On each area three site quality classes were chosen for each tree species. The site classes were chosen to represent poor, medium, and good sites typical for each area. Free amino acids in the needles were analyzed as 9-fluorenylmethyl formate derivatives by high-performance liquid chromatography. The total nitrogen was determined with a CHN elemental analyzer, and other mineral nutrients were determined with an inductively coupled plasma analyzer. Arginine, glutamic acid, glutamine, γ-aminobutyric acid, and aspartic acid were the quantitatively dominating amino acids in the needles of both species from all sites in both northern and southern Sweden. These amino acids represented 50–80% of the total concentration of free amino acids in the needles. The concentration of arginine in the needles of both spruce and pine increased with decreasing site index and showed high variations between individual trees. For both species, the highest concentrations of arginine were found in the southern area, which had the highest deposition of nitrogen. Concentrations of glutamic acid, glutamine, and γ-aminobutyric acid in the needles of both species showed significant differences between some of the sites on both areas, but these differences showed no general pattern that correlated with the site indexes. In relation to nitrogen, low concentrations of phosphorus and potassium were found in needles from the poorest spruce sites in both areas compared with corresponding values for the good spruce sites. The results are discussed in relation to nitrogen deposition and mineral nutrient imbalance.

Effects of Hypothermia, Pentobarbital, and Isoflurane on Postdepolarization Amino Acid Release during Complete Global Cerebral Ischemia

1996 ◽  
Vol 85 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Ken Nakashima ◽  
Michael M. Todd
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Cerebral Ischemia ◽  
Excitatory Amino Acids ◽  
High Performance ◽  
Excitatory Amino Acid ◽  
Protective Efficacy ◽  
Aminobutyric Acid ◽  
Global Cerebral Ischemia ◽  
Gamma Aminobutyric Acid

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.

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
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Essential Amino Acids ◽  
Tissue Level ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Tissue Concentrations ◽  
Dog Brain ◽  
Total Pool ◽  
Significant Uptake

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.

scholarly journals Rabbit Carcasses for Use in Feline Diets: Amino Acid Concentrations in Fresh and Frozen Carcasses With and Without Gastrointestinal Tracts

2021 ◽  
Vol 7 ◽  
Author(s):  
Tammy J. Owens ◽  
Andrea J. Fascetti ◽  
C. Christopher Calvert ◽  
Jennifer A. Larsen
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Crude Protein ◽  
Protein Body ◽  
National Research Council ◽  
Body Water ◽  
Taurine Supplementation ◽  
Frozen Ground ◽  
Taurine Deficiency ◽  
Amino Acid Concentrations

Whole-prey diets for exotic feline species are common, and this practice has also increased in popularity for domestic cats. However, prior analyses of prey indicate possible essential amino acid inadequacy, and dilated cardiomyopathy from taurine deficiency was reported in cats fed whole ground rabbit. Crude protein, body water, and amino acid concentrations were evaluated in fresh and frozen ground rabbits with (n=10) or without (n = 10) gastrointestinal tracts. Amino acids were greater in fresh samples without gastrointestinal tracts (p < 0.05) except taurine, glycine, and cysteine. When normalized for protein content, only glutamate, alanine, methionine, isoleucine, tyrosine, lysine, histidine, and arginine were greater in fresh rabbits without gastrointestinal tracts (g/16 g N basis; p < 0.05). Freezing at −18°C for 30 days had no effect on crude protein or body water content. After freezing, only methionine was lower and only proline was higher when gastrointestinal tracts were omitted (g/16 g N basis; p < 0.05). Regardless, all essential amino acids except taurine exceeded Association of American Feed Control Officials and National Research Council nutrient recommendations for all feline life stages. In contrast, there was minimal impact of treatment on taurine concentrations. However, although feline taurine requirements for prey and other raw or fresh food diets remain undefined, none of the rabbit samples met any recommendation for taurine concentrations for commercial canned or dry extruded diets, ranging from 20 to 90% of the minimum values. Taurine supplementation is recommended when feeding rabbit to cats. Determination of taurine requirements of cats fed whole-prey diets is warranted.

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