A New Procedure for the Measurement of Acid‐soluble Glutamine of Tissue With Particular Reference to the Brain

Dobkin, J.; Marton, M

doi:10.1111/j.1471-4159.1970.tb02205.x

Cited by 11 publications

(11 citation statements)

References 6 publications

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“…In this approach, we observed a transient disappearance of myelinated fibers in the affected regions. Experimentally induced excessive neuronal activity (electroconvulsion, kainic acid, pilocarpine, pentylenetetrazole) is known to lead to glial activation and increased glutamate levels [24,70,71]. These events also affect and destroy myelin-forming oligodendrocytes through excitatory cell stress, a phenomenon which might be mirrored by the decrease in Black Gold staining [25 -27].…”

Section: Myelination In the Hippocampus Following Lesion And Seizurementioning

confidence: 99%

Myelination in the hippocampus during development and following lesion

Meier

Bräuer

Heimrich

et al. 2004

Cellular and Molecular Life Sciences (CMLS)

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Myelin is crucial for the stabilization of axonal projections in the developing and adult mammalian brain. However, myelin components also act as a non-permissive and repellent substrate for outgrowing axons. Therefore, one major factor which accounts for the lack of axonal regeneration in the mature brain is myelin. Here we report on the appearance of mature, fully myelinated axons during hippocampal development and following entorhinal lesion with the myelin-specific marker Black Gold. Although entorhinal axons enter the hippocampal formation at embryonic day 17, light and ultrastructural analysis revealed that mature myelinated fibers in the hippocampus occur in the second postnatal week. During postnatal development, increasing numbers of myelinated fibers appear and the distribution of myelinated fibers at postnatal day 25 was similar to that found in the adult. After entorhinal cortex lesion, a specific anterograde denervation in the hippocampus takes place, accompanied by a long-lasting loss of myelin. Quantitative analysis of myelin and myelin breakdown products at different time points after lesion revealed a temporally close correlation to the degeneration and reorganization pha-ses in the hippocampus. In contrast, electroconvulsive seizures resulted in brief demyelination and a faster recovery time course. In conclusion, we could show that the appearance of mature axons in the hippocampus is temporally regulated during development. In the adult hippocampus, demyelination was found after anterograde degeneration and also following seizures, suggesting that independent types of insult lead to demyelination. Reappearing mature axons were found in the hippocampus following axonal sprouting. Therefore, our quantitative analysis of mature axons and myelination effectively reflects the readjusted axonal density and possible electrophysiological balance following lesion.

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Section: Myelination In the Hippocampus Following Lesion And Seizurementioning

confidence: 99%

Myelination in the hippocampus during development and following lesion

Meier

Bräuer

Heimrich

et al. 2004

Cellular and Molecular Life Sciences (CMLS)

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“…Determination ofglutamine andglutamic acid. Samples of frozen brain tissue were extracted with 10% TCA, and glutamine was estimated on a portion of the extract by the procedure described in the preceding paper (DOBKIN and MARTON, 1969). The Dow 1-X8 resin 200-400 mesh was used to separate glutamic acid.…”

Section: Methodsmentioning

confidence: 99%

Reversible Changes in Glutamine Levels in the Cat Cerebral Cortex Evoked by Afferent Electrical Stimulation and by Administration of Pentamethylenetetrazole (Pentylenetetrazol)

Dobkin¹

1970

Journal of Neurochemistry

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1. Levels of glutamine and glutamate were measured in cat cerebral cortex rapidly frozen in situ after 30 sec of afferent electrical stimulation (AES) of the contralateral brachial plexus. A substantial decrease in glutamine and a minor one in glutamate were found as compared to the ipsilateral cortex. The fall in glutamine was found to be reversed very shortly after break of the current.2. Glutamine levels of the cortex determined after rapid freezing in situ were found to fluctuate with the diverse stages of periodic convulsions induced by pentylenetetrazol (PTZ): glutamine was substantially decreased during the initial part of the first clonictonic convulsion, it returned to the normal value in its termination stage and remained so at the commencement of the interictal recovery period, dropping again shortly before the onset and in the course of the second convulsion. The second drop in glutamine was accompanied by a decrease of glutamate. In the comatose state which followed convulsions, both glutamine and glutamate were again at their original concentrations. 3.The results suggest that the view of the metabolic stability of brain glutamine under cerebral stimulation-based on past reports-should be modified in the sense that glutamine is labilized by excitation, but this effect is obscured by the counteracting process of synthesis de novo.4. The significance of the data reported here, in relation to the incidence and termination of convulsions, as well as the mechanisms which may be involved in the observed fall and restitution of the level of cerebral glutamine, are discussed. THE FREE (acid-soluble) glutamine present in the brain has generally been classed among the most physiologically active cerebral amino acids, not only because of its high concentration, but also because of the important role played by the glutamineglutamic acid system in the mechanism of ammonia removal in the brain (WEIL-MALHERBE, 1950) and furthermore, because of the significance of glutamine as the main nitrogenous nutrient passing the blood-brain barrier (SCHWERIN, BESSMANN and WAELSCH, 1950).Several authors who studied glutamine levels in the brain of experimental animals, using the technique of rapid freezing, reported data obtained under electrical stimulation and drug-induced convulsions. Glutamine in the brain of rats and mice was found to be either unchanged ( RICHTER and DAWSON, 1948;DAWSON, 1951) or increased (KAMRIN and KAMRIN, 1961) by electroshock-produced seizures. On application of current to the extremities of rats in a procedure not evoking convulsions, an increase was observed by VLADIMIROVA (1954) after 1-2 min and by TSUKADA, TAKAGAKI, SUGIMOTO and HIRANO (1958) only after at least half an hour. No significant changes were observed in the cerebral glutamine level after brief (20-30 sec) pentylenetetrazol (PTZ)-induced seizures (KAMRIN and KAMRIN, 1961 ; TEWS, CARTER, ROA and STONE, 1963) nor after a longer (30-40 min) convulsive activity Abbreviations used: AES, afferent electrical stimulation; PTZ, pentamethylen...

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“…The steady-state level of glutamine in hypothalamus and hippocampus was estimated spectrophotometrically by the method of Dobkin and Marton [25]. The levels of brain regional GABA, glutamate and glutamine were expressed as lg/mg protein.…”

Section: Estimation Of Biochemical Parametersmentioning

confidence: 99%

Long-term Exposure of Variable Dietary Protein-to-Carbohydrate Ratio: Effect on Brain Regional Glutamatergic Activity with Age

Pal

Poddar

2007

Neurochem Res

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Glutamatergic activity of hypothalamus and hippocampus of young (3 months) male albino rats having normal diet [protein (20%)-carbohydrate (68%)] was increased with the increase of age. Long-term (60 consecutive days) feeding of low protein (8%)-high carbohydrate (80%) diet (LP-HC) increased glutamatergic activity in these brain regions of young rats and decreased that in aged (18 months). On the contrary, supplementation of high protein (50%)-low carbohydrate (38%) diet (HP-LC) under similar condition decreased glutamatergic activity in those brain regions of young and increased that in aged brain regions. Thus, prolonged exposure of LP-HC diet may damage young brain; whereas, HP-LC diet under similar condition causes excitotoxicity to aged brain. Therefore, considering the present scenario in relation to metabolism and receptor activity of glutamatergic system, it may be suggested that long-term consumption of LP-HC and HP-LC diets modulate the brain regional glutamatergic activity reversibly with age.

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A New Procedure for the Measurement of Acid‐soluble Glutamine of Tissue With Particular Reference to the Brain

Cited by 11 publications

References 6 publications

Myelination in the hippocampus during development and following lesion

Myelination in the hippocampus during development and following lesion

Reversible Changes in Glutamine Levels in the Cat Cerebral Cortex Evoked by Afferent Electrical Stimulation and by Administration of Pentamethylenetetrazole (Pentylenetetrazol)

Long-term Exposure of Variable Dietary Protein-to-Carbohydrate Ratio: Effect on Brain Regional Glutamatergic Activity with Age

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