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Rowley NM, Madsen KK, Schousboe A, Steve White H. Glutamate and GABA synthesis, release, transport and metabolism as targets for seizure control. Neurochem Int 2012; 61:546-58. [PMID: 22365921 DOI: 10.1016/j.neuint.2012.02.013] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 02/09/2012] [Indexed: 11/17/2022]
Abstract
The synthesis, release, reuptake, and metabolism of the excitatory and inhibitory neurotransmitters glutamate and GABA, respectively, are tightly controlled. Given the role that these two neurotransmitters play in normal and abnormal neurotransmission, it is important to consider the processes whereby they are regulated. This brief review is focused entirely on the metabolic aspects of glutamate and GABA synthesis and neurotransmission. It describes in limited detail the synthesis, release, reuptake, metabolism, cellular compartmentation and pharmacology of the glutamatergic and GABAergic synapse. This review also provides a summary and brief description of the pathologic and phenotypic features of the various genetic animal models that have been developed in an effort to provide a greater understanding of the role that each of the aforementioned metabolic processes plays in controlling excitatory and inhibitory neurotransmission and how their use will hopefully facilitate the development of safer and more efficacious therapies for the treatment of epilepsy and other neurological disorders.
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Affiliation(s)
- Nicole M Rowley
- Department of Pharmacology and Toxicology, Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, USA
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Salazar P, Tapia R. Seizures induced by intracerebral administration of pyridoxal-5'-phosphate: effect of GABAergic drugs and glutamate receptor antagonists. Neuropharmacology 2001; 41:546-53. [PMID: 11587709 DOI: 10.1016/s0028-3908(01)00110-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pyridoxal-5'-phosphate (PLP), the cofactor of glutamate decarboxylase, paradoxically induces convulsions when injected intracranially in adult mammals. We have tested the effect of some GABAergic and antiglutamatergic drugs on the behavioral and electroencephalographic (EEG) seizures produced by intracerebroventricular (i.c.v.) microinjection of 1 micromol PLP in the rat. PLP induced barrel turning, running fits and tonic-clonic convulsions, which started 5-10 min after recovery from the anesthesia (halothane), peaked at 20 min and disappeared at about 50 min. These symptoms were accompanied by frequent high amplitude EEG spike burst discharges. Pyridoxal, pyridoxamine-5'-phosphate or deoxypyridoxine were ineffective. The i.c.v. microinjection of the GABAergic compounds muscimol, isoguvacine, aminooxyacetic acid or GABA itself, significantly protected against PLP effects. In contrast, the NMDA receptor antagonists MK-801 and the non-NMDA receptor antagonist NBQX, failed to protect and induced motor alterations and mortality. We conclude that a temporary decrease of the GABA(A) receptor function is involved in the convulsant effect of PLP. This decrease might be due to the formation of a Schiff base between the carbonyl group of PLP and the epsilon-amino group of a functionally crucial lysine residue located in one extracellular loop of the GABA(A) receptor.
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Affiliation(s)
- P Salazar
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, 04510, Mexico, DF, Mexico.
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Labiner DM, Yan CC, Weinand ME, Huxtable RJ. Disturbances of amino acids from temporal lobe synaptosomes in human complex partial epilepsy. Neurochem Res 1999; 24:1379-83. [PMID: 10555778 DOI: 10.1023/a:1022528522373] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have studied the levels of neuroactive amino acids in synaptosomes (P2 fraction) isolated from brain tissue of ten patients with medically intractable epilepsy who were undergoing temporal lobectomy. First, lateral temporal tissue (nonfocal) was removed followed by medial temporal tissue (focal). A synaptosomal fraction (P2) was immediately prepared from each tissue and analyzed for free amino acid concentrations. Statistically significant reductions were seen in glutamine and GABA concentrations in focal tissue compared to nonfocal tissue. The ratio of excitatory amino acids (aspartate and glutamate) to inhibitory amino acids (taurine and GABA) was significantly higher in focal tissue compared to nonfocal. The glutamine/glutamate ratio was significantly reduced. These data support the hypothesis that alterations in the balance between excitatory and inhibitory amino acids may be involved in the expression of epilepsy.
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Affiliation(s)
- D M Labiner
- Department of Neurology, University of Arizona Tucson, 85724, USA
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Saxena AK, Saxena M. Developments in anticonvulsants. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1995; 44:185-291. [PMID: 7644666 DOI: 10.1007/978-3-0348-7161-7_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- A K Saxena
- Division of Medicinal Chemistry, Central Drug Research Institute, Lucknow, India
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Tapia R, Salazar P. Glutamate decarboxylase activity in the substantia nigra and the hippocampus of rats microinjected with inhibitors of the enzyme. Neurochem Res 1991; 16:263-7. [PMID: 1780027 DOI: 10.1007/bf00966089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Three inhibitors of glutamate decarboxylase (GAD), acting through different mechanisms, as well as pyridoxal phosphate (PLP), were microinjected unilaterally by stereotaxic procedures into the substantia nigra reticulata or the CA1 area of the hippocampus of the rat. The inhibitors used were thiosemicarbazide (TSC), gamma-glutamyl hydrazide and the PLP-glutamyl-hydrazone (PLPGH) formed by the combination of the latter with PLP. No behavioral alterations were observed after the administration of any of the drugs used, in any of the two brain regions studied. When measured in the absence of exogenous PLP, GAD activity in the substantia nigra injected with TSC was diminished by about 35%, and no changes were observed with the other drugs. In the CA1 hippocampal area both TSC and PLPGH inhibited GAD by more than 50%, and this inhibition was not reversed by PLP added in vitro. The results are discussed in terms of the possible explanation for the differences between the drugs used and for the lack of effects of GAD inhibition on the behavior of the animals.
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Affiliation(s)
- R Tapia
- Departamento de Neurociencias, Universidad Nacional Autónoma de México
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Abdul-Ghani AS, Ghneim H, el-Lati S, Saca'an A. Changes in the activity of glutamate related enzymes in cerebral cortex, during insulin-induced seizures. Int J Neurosci 1989; 44:67-74. [PMID: 2577218 DOI: 10.3109/00207458908986184] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The activity of glutamate related enzymes and the concentration of glutamine, glutamate and gamma-amino n-butyric acid (GABA) were investigated in the cerebral cortex of rats, in different stages of insulin-induced hypoglycemia. Hypoglycemia was produced by intraperitoneal injection of insulin 0.05-100 units per kg body weight. The minimum required dose to produce irreversible severe hypoglycemia was 0.5 units/kg. In 85% of the cases an insulin induced hypoglycemic convulsion, was achieved 130-150 minutes after injection. Blood glucose levels during insulin induced seizures ranged between 8-15 mg%. In the range of 0.5-100 u insulin/kg the degree of hypoglycemia and the onset of convulsions were identical. The concentration of glutamine was significantly reduced during convulsive and postconvulsive stages. Glutamate and GABA concentrations were reduced significantly in all stages of insulin-induced hypoglycemia. The decrease in glutamine concentration was concurrent with an increase in the activity of its degradative enzyme, glutaminase. This was apparent at the preconvulsive, convulsive and postconvulsive stages. The activity of other enzymes related to energy production such as glutamate dehydrogenase (GDH), glutamate transaminase (GPT) and aspartate aminotransferase (AAT) were also increased. The activity of glutamine synthase (GS) was unaffected by hypoglycemia. Insulin induced changes in glutamine, glutamate and their related enzymes could not be attributed to convulsion since a similar pattern of changes was observed in the preconvulsive and postconvulsive stages, and no changes were detected following picrotoxin-induced seizures.
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Affiliation(s)
- A S Abdul-Ghani
- Biology and Biochemistry Department, Faculty of Science, Birzeit University, Occupied West Bank
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Löscher W. gamma-Acetylenic GABA antagonizes the decrease in synaptosomal GABA concentrations but not the seizures induced by 3-mercaptopropionic acid in rats. Biochem Pharmacol 1986; 35:3176-80. [PMID: 3753526 DOI: 10.1016/0006-2952(86)90408-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Iadarola MJ, Gale K. Cellular compartments of GABA in brain and their relationship to anticonvulsant activity. Mol Cell Biochem 1981; 39:305-29. [PMID: 6273710 DOI: 10.1007/bf00232582] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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9
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Toth J, Lajtha A. Drug-induced changes in the composition of the cerebral free amino acid pool. Neurochem Res 1981; 6:3-12. [PMID: 7012655 DOI: 10.1007/bf00963900] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The effects of insulin, hydroxybutyrate, deoxypyridoxine, chlorpromazine, codeine, morphine, puromycin, and cycloheximide on the composition of the free amino acids in mouse and rat brain were tested. Significant changes occurred in a number of amino acids with most compounds tested; the largest was of alanine (a 50% increase with glucose, a 50% decrease with drugs); histidine was often increased, and the nonessential amino acids were mostly decreased. The pattern of changes was somewhat different in the mouse brain from that in the rat brain. Changes of amino acid levels may participate in the pharmacological action of a number of compounds.
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Abstract
The hypothesis that certain amino acid analogues possessing a five-membered ring structure or amino acid analogues that can be viewed as fragments derived from such a ring would have anticonvulsant activity was proposed and tested. The compounds 1-aminocyclopentane carboxylic acid, 1-amino-3-methylcyclopentane carboxylic acid, 3-aminotetrahydrothiophene carboxylic acid, and alpha-aminoisobutyric acid were found to protect rats against seizures in the maximal electroshock test but offered no protection against metrazol- (pentylenetetrazol) induced seizures in mice. The structural feature of this class of anticonvulsants that allows for hydrophobic interactions at the receptor site is considered to be a major physical factor necessary in promoting the activity of this class of anticonvulsants.
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Abstract
Experimental procedures are described which are believed to yield results that reflect, within certain limits, the in vivo changes of the size of the GABA pool in nerve endings in comparison with those of all other GABA pools. Two irreversible GABA-T inhibitors, vinyl GABA and acetylenic GABA, two GAD inhibitors, 3-mercaptopropionic acid and pyridoxal phosphate glutamyl-gamma-hydrazone, and di-n propylacetate, a clinically useful anticonvulsant, have been studied to determine their effects on GABA compartmentalization in mouse brain cortex. The changes elicited by these drugs in subcellular fractions of brain cortex homogenates support the notion that measurement of amino acid concentrations in crude synaptosomal fractions and in supernatant fractions under controlled conditions allow one to draw conclusions about relative changes of pool sizes in vivo. In particular this work showed that a specific increase in the concentration of GABA within the nerve endings is more important than a large increase of total brain GABA as a means of decreasing susceptibility to a variety of chemically or physically induced seizures.
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Abstract
The biochemical and behavioral effects of the anticonvulsant amino-oxyacetic acid (AOAA) have been studied in a model of focal penicillin seizures in rats. At 20 mg/Kg AOAA treatment results in a progressive 11 fold increase in GABA levels in cortex over three hours. There is a decrease in aspartate, ketoglutarate, alanine and glutamine, and an initial decrease followed by an increase in pyruvate and glutamate. These results reflect a functional inhibition of several B-6 dependent aminotransferase enzymes. When rats are pretreated 30 min before the onset of focal penicillin seizures there is a 60% reduction in the number of discharges and a 34% reduction in seizure duration. Pretreatment beyond 75 min results in progressively less anticonvulsant effect, such that seizures eventually become more severe than control. There is an increase in the number and duration of discharges, seizure spikes become complex, and tonic-clonic events develop. Penicillin seizures do not cause a change in levels of GABA, but result in a decrease in glutamate within the focus. AOAA pretreatment initially prevents this decrease in glutamate but later accentuates it. The biochemical effects of AOAA are complex, but biphasic anticonvulsant properties coincide in time with a change in the balance of excitatory and inhibitory amino acids in the seizure focus.
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Stone WE, Javid MJ. Effects of prior administration of methionine sulfoximine on the thresholds of seizures induced in mice by 3-mercaptopropionic acid or pentylenetetrazol. Biochem Pharmacol 1978; 27:2972-3. [PMID: 736990 DOI: 10.1016/0006-2952(78)90221-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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15
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Löscher W, Frey HH. Aminooxyacetic acid: correlation between biochemical effects, anticonvulsant action and toxicity in mice. Biochem Pharmacol 1978; 27:103-8. [PMID: 619891 DOI: 10.1016/0006-2952(78)90263-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Matin MA, Kar PP, Hasan MZ, Anand M. Comparison of the chronic effects of alpha-chlordane and pp' DDT on the level of cerebral amino acids and free ammonia in mice. PHARMACOLOGICAL RESEARCH COMMUNICATIONS 1977; 9:613-9. [PMID: 896901 DOI: 10.1016/s0031-6989(77)80091-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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17
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Gaitonde MK, Festing MF. Brain glutamic acid decarboxylase and open field activity in ten inbred strains of mice. Brain Res 1976; 103:617-21. [PMID: 1252948 DOI: 10.1016/0006-8993(76)90465-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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18
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Tapia R. Evidence for a synthesis-dependent release of GABA. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1976; 69:385-94. [PMID: 941743 DOI: 10.1007/978-1-4684-3264-0_28] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Tapia R, Sandoval ME, Contreras P. Evidence for a role of glutamate decarboxylase activity as a regulatory mechanism of cerebral excitability. J Neurochem 1975; 24:1283-5. [PMID: 1127441 DOI: 10.1111/j.1471-4159.1975.tb03915.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Tapia R, Pasantes-Morales H, Taborda E, Pérez de la Mora M. Seizure susceptibility in the developing mouse and its relationship to glutamate decarboxylase and pyridoxal phosphate in brain. JOURNAL OF NEUROBIOLOGY 1975; 6:159-70. [PMID: 171340 DOI: 10.1002/neu.480060204] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The relationship between the susceptibility to convulsions, the content of pyridoxal 5'-phosphate and the activity of pyridoxal kinase (EC 2.7.1.35) and glutamate decarboxylase (EC 4.1.1.15) in brain, was studied in the developing mouse. Seizures were induced by pyridoxal phosphate-gamma-glutamyl hydrazone (PLPGH), a drug previously reported to reduce the levels of pyridoxal 5'-phosphate and as a consequence to inhibit the activity of glutamate decarboxylase in brain of adult mice. It was found that the seizure pattern, as well as the time of appearance of convulsions, differed between 2- and 5-day old mice and 10-day old or older mice, indicating a progressive increase in seizure susceptibility during development. In brain, pyridoxal kinase activity and pyridoxal 5'-phosphate levels were decreased by the administration of PLPGH at all ages studied, whereas glutamate decarboxylase activity was inhibited less than 25% in 2- and 5-day old mice, and about 50% thereafter. Parallelly, the activation of glutamate decarboxylase by pyridoxal 5'-phosphate added in vitro to control homogenates was less in 2- and 5-day old mice than in older animals. It is concluded that the increase in the susceptibility to seizures induced by PLPGH during development is probably related to the increase observed in the sensitivity of glutamate decarboxylase in vivo to a decrease of pyridoxal 5'-phosphate levels. The correlation between pyridoxal 5'-phosphate, glutamate decarboxylase, and seizure susceptibility seems to be established at about 10 days of age.
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Abstract
The knowledge that GABA is an inhibitory neurotransmitter substance in brain has spurred a prodigious research effort to implicate GABA in the etiology of seizures. Such an involvement for GABA can occur theoretically at either of two levels, at the level of its metabolism or at the level of its functioning. Convulsant agents such as picrotoxin and bicuculline appear to act by impairing the functioning of GABA at the postsynaptic receptor site, but virtually nothing is known about the attendant molecular events although a major expansion of knowledge in this area may be expected within the next decade. In contrast, a vast amount of data has accumulated with respect to changes in GABA metabolism induced by convulsant agents such as the hydrazines, hydrazides, and hyperbaric oxygen. The problem in this case lies in the interpretation of the data. Are the changes in GABA metabolism the cause of the seizures? There is clearly no simple relationship between seizure activity and any single parameter of GABA metabolism, be it the GABA content of the brain, or the rate of uptake of GABA by cellular components, or the activity of the GABA-synthesizing and degrading enzyme systems, GAD and GABA-T respectively. This finding may, however, be illusory since the parameters of GABA metabolism were in most cases measured using preparations from intact brain tissue. Observed changes in the parameters may not accurately reflect events at a critical subcellular location such as the synaptic cleft. Thus there may well be a simple relationship between the concentration of GABA in the synaptic cleft and seizure activity. Unfortunately the limitations of current technology preclude the testing of this possibility. The author has, however, developed an equation on an empirical basis which provides an excellent relationship between the excitable state of the brain and a function of GABA metabolism which incorporates both changes in GABA level and changes in GAD activity. This equation has been used successfully to explain and rationalize previously anomalous results with respect to changes in GABA metabolism associated with the action of both convulsant and anticonvulsant agents. The concept embodied in the equation is that the excitable state of brain is determined primarily by the rate of synthesis of GABA but that reflects changes in the concentration of GABA in the synaptic cleft has been suggested.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J D Wood
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Canada
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Bell JA, Anderson EG. Dissociation between amino-oxyacetic acid-induced depression of spinal reflexes and the rise in cord GABA levels. Neuropharmacology 1974; 13:885-94. [PMID: 4154420 DOI: 10.1016/0028-3908(74)90044-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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23
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Tapia R, Sandoval ME. Possible participation of gamma-aminobutyric acid in the regulation of protein synthesis in brain, in vivo. Brain Res 1974; 69:255-63. [PMID: 4823094 DOI: 10.1016/0006-8993(74)90005-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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24
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Kar PP, Matin MA. Possible role of cerebral amino acids in acute neurotoxic effects of DDT in mice. Eur J Pharmacol 1974; 25:36-9. [PMID: 4154845 DOI: 10.1016/0014-2999(74)90091-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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25
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Fischer MH, Harm JW, Waisman HA. A preliminary biochemical examination of micrencephalic rat brains. Biochem Pharmacol 1973; 22:267-71. [PMID: 4763254 DOI: 10.1016/0006-2952(73)90279-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Wood JD, Peesker SJ. A correlation between changes in GABA metabolism and isonicotinic acid hydrazide-induced seizures. Brain Res 1972; 45:489-98. [PMID: 4634321 DOI: 10.1016/0006-8993(72)90477-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Abstract
1. The effects of amino-oxyacetic acid (AOAA) on the central nervous system and on skeletal muscle have been examined in the chicken.2. AOAA had both anticonvulsant and convulsant effects, depending on the dose, as in other species.3. The convulsant effect, accompanied by EEG spiking, decreased rapidly with increase in age of young chicks.4. The convulsant effect was exerted primarily through supraspinal centres.5. Of control depressants tested, only troxidone and small doses of AOAA afforded significant protection against AOAA seizures.
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Meldrum BS, Horton RW. Convulsive effects of 4-deoxypyridoxine and of bicuculline in photosensitive baboons (Papio papio) and in rhesus monkeys (Macaca mulatta). Brain Res 1971; 35:419-36. [PMID: 5002707 DOI: 10.1016/0006-8993(71)90485-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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29
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Tapia R, Sandoval ME. Study on the inhibition of brain glutamate decarboxylase by pyridoxal phosphate oxime-O-acetic acid. J Neurochem 1971; 18:2051-9. [PMID: 4942967 DOI: 10.1111/j.1471-4159.1971.tb05064.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Tapia R, Pasantes H. Relationships between pyridoxal phosphate availability, activity of vitamin B 6 -dependent enzymes and convulsions. Brain Res 1971; 29:111-22. [PMID: 5564253 DOI: 10.1016/0006-8993(71)90421-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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31
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Wood JD, Abrahams DE. The comparative effects of various hydrazides on -aminobutyric acid and its metabolism. J Neurochem 1971; 18:1017-25. [PMID: 5567895 DOI: 10.1111/j.1471-4159.1971.tb12031.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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32
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Leonard BE, Tonge SR. Some effects of an hallucinogenic drug (phencyclidine) on neurohumoral substances. LIFE SCIENCES. PT. 1: PHYSIOLOGY AND PHARMACOLOGY 1970; 9:1141-52. [PMID: 5481738 DOI: 10.1016/0024-3205(70)90147-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Sze PY, Lovell RA. A reexamination of the effect of thiosemicarbazide on brain GABA and glutamic decarboxylase in vivo. LIFE SCIENCES. PT. 1: PHYSIOLOGY AND PHARMACOLOGY 1970; 9:889-99. [PMID: 5478396 DOI: 10.1016/0024-3205(70)90051-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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34
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Tapia R, Pasantes H, Massieu G. Some properties of glutamate decarboxylase and the content of pyridoxal phosphate in brains of three vertebrate species. J Neurochem 1970; 17:921-5. [PMID: 5426680 DOI: 10.1111/j.1471-4159.1970.tb02245.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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35
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Ghittoni NE, Sellinger OZ. Cerebral methionine and cysteine levels in rats after injection of the convulsant methionine sulfoximine. ACTA ACUST UNITED AC 1970. [DOI: 10.1016/s0031-6989(70)80018-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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36
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Tapia R, Pérez de la Mora M, Massieu GH. Correlative changes of pyridoxal kinase pyridoxal-5'-phosphate and glutamate decarboxylase in brain, during drug-induced convulsions. Ann N Y Acad Sci 1969; 166:257-66. [PMID: 5262020 DOI: 10.1111/j.1749-6632.1969.tb54276.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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38
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Baxter CF. Changes in gamma-aminobutyric-acid-shunt enzymes and substrates after administration of carbonyl reagents and vitamin B6 in vivo: an apparent discrepancy in assay techniques. Ann N Y Acad Sci 1969; 166:267-80. [PMID: 5262021 DOI: 10.1111/j.1749-6632.1969.tb46395.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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39
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Baxter CF. CHANGES IN GAMMA-AMINOBUTYRIC-ACID-SHUNT ENZYMES AND SUBSTRATES AFTER ADMINISTRATION OF CARBONYL REAGENTS AND VITAMIN B 6IN VIVO: AN APPARENT DISCREPANCY IN ASSAY TECHNIQUES. Ann N Y Acad Sci 1969. [DOI: 10.1111/j.1749-6632.1969.tb54277.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Tews JK. PYRIDOXINE DEFICIENCY AND BRAIN AMINO ACIDS. Ann N Y Acad Sci 1969. [DOI: 10.1111/j.1749-6632.1969.tb54258.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Tapia R, Awapara J. Effects of various substituted hydrazones and hydrazines of pyridoxal-5'-phosphate on brain glutamate decarboxylase. Biochem Pharmacol 1969; 18:145-52. [PMID: 5780984 DOI: 10.1016/0006-2952(69)90019-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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