Intraneuronal effects of inhibitory amino acids

1980 ◽  
Vol 58 (2) ◽  
pp. 193-204 ◽  
Author(s):  
A. Constanti ◽  
K. Krnjević ◽  
A. Nistri
Keyword(s):  
Amino Acids ◽  
Transport Mechanism ◽  
Input Resistance ◽  
Aminobutyric Acid ◽  
Spinal Motoneurons ◽  
Gaba Transport ◽  
Aminoisobutyric Acid ◽  
Intracellular Release ◽  
Comparable Effect ◽  
Inhibitory Amino Acids

Injections of γ-aminobutyric acid (GABA) into spinal motoneurons (in cats under Dial) induce a small but relatively prolonged hyperpolarization (mean −1.7 mV, SD 2. 1; n = 25), which is associated with a rise in input resistance (mean 44%, SD 122; n = 34), is not reversed by hyperpolarization, and is not potentiated by intracellular release of benzodiazepines. Muscimol sometimes has a comparable effect, but α-aminoisobutyric acid and glycine do not. These observations are consistent with the possibility that motoneurons have a Na+-coupled GABA transport mechanism that is electrogenic and can be reversed by an excess of intracellular GABA.

Bicuculline, benzyl penicillin, and inhibitory amino acids in the spinal cord of the cat

1977 ◽  
Vol 55 (3) ◽  
pp. 670-680 ◽  
Author(s):  
K. Krnjević ◽  
E. Puil ◽  
R. Werman
Keyword(s):  
Spinal Cord ◽  
Input Resistance ◽  
Aminobutyric Acid ◽  
Membrane Properties ◽  
Gaba Uptake ◽  
Spinal Motoneurons ◽  
Benzyl Penicillin ◽  
Equal Chance ◽  
Conductance Increase ◽  
Inhibitory Amino Acids

Bicuculline methochloride (BMC), applied by microiontophoresis, tends to depolarize spinal motoneurons and lower their input resistance. With approximately equal iontophoretic currents of γ-aminobutyric acid (GABA) and BMC, there is an almost equal chance of observing no change, a potentiation, or a depression of the GABA-evoked conductance increase. A block of the GABA action is seen consistently only when the iontophoretic current of BMC is at least double that of GABA. Under these conditions BMC can selectively antagonize GABA without blocking the effects of glycine, though the latter can also be blocked by larger amounts of BMC. BMC also regularly eliminates the usual apparent desensitization to GABA. This may be due to depression of GABA uptake by BMC, which would also account for its potentiating action at lower relative doses. Comparable effects are observed with iontophoretic applications of benzyl penicillin (BP); but even large doses of BP produce no definite change in membrane properties or in conductance increase evoked by GABA or glycine.

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.

Nitrogen metabolism of Picea glauca. II. Diurnal changes of free amino acids, amides, and guanidino compounds in roots, buds, and leaves during the onset of dormancy of white spruce saplings

1968 ◽  
Vol 46 (7) ◽  
pp. 921-928 ◽  
Author(s):  
D. J. Durzan
Keyword(s):  
Amino Acids ◽  
Picea Glauca ◽  
Weight Basis ◽  
Aminobutyric Acid ◽  
Soluble Nitrogen ◽  
Diurnal Changes ◽  
Fresh Weight ◽  
Fresh Weight Basis ◽  
Plant Parts ◽  
Guanidino Compounds

In late August during the onset of dormancy in spruce, seasonal levels of soluble nitrogen, rich in arginine, were high. On a fresh weight basis, diurnal levels of total soluble nitrogen and most component amino acids in roots, buds, and leaves showed maxima, one at sunrise and another in the afternoon or near sunset.Arginine and glutamine in the different plant parts contributed 44 to 83% to the alcohol-soluble nitrogen. In buds and leaves, percentage of arginine remained high and decreased slightly at midday, whereas in roots a continual drop occurred. In all organs examined, changes in glutamine reflected the double maxima of total soluble nitrogen and were greatest in roots.On a fresh weight basis, most amino acids accumulated at sunrise and near sunset; however a few especially in leaves, increased at midday, e.g. glutamic and aspartic acid, lysine, γ-aminobutyric acid, and serine.Comparison of levels of free guanidino compounds in different organs showed remarkable out-of-phase patterns. Levels of these compounds are known from 14C-arginine studies to be closely related to the metabolism of arginine.

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