%0 Journal Article
%~ Pubmed
%A Nasrallah, Fatima A
%A Balcar, Vladimir J
%A Rae, Caroline D
%T Activity-dependent ?-aminobutyric acid release controls brain cortical tissue slice metabolism.
%B Journal of neuroscience research
%D 2011
%V 89
%N 12
%P 1935-45
%@ 1097-4547
%X Vigabatrin (?-vinyl-GABA) is an irreversible inhibitor of the enzyme ?-aminobutyric acid (GABA) transaminase. It has been shown to increase levels of GABA in brain and result in increased release of GABA from nonsynaptic sources following activation. Here, we use a guinea pig cortical tissue slice model to identify the metabolic sequelae of vigabatrin when incubated with tissue slices alone or when the tissue slices were activated by ligands with targeted activating mechanisms. We show that incubation of slices with AMPA, the group II metabotropic glutamate antagonist EGLU [(2S)-?-ethylglutamic acid], or the GABA(B) R antagonist CGP 52432 in the presence of vigabatrin produces very similar metabolic profiles, consistent with the large-scale turning off of metabolic activity. This effect is blocked by the GABA(Arho) antagonist TPMPA [(1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid]. Taken together, these results suggest that GABA, released following activation, acts on extrasynaptic receptors consistent with GABA(Arho) and that these receptors act as a kind of "master switch" that is capable of turning off a range of differently induced activities.
%Z FOR Codes: 110901



%0 Journal Article
%~ Pubmed
%A Ser?, Omar
%A S?astn?, Franti?ek
%A Zvolsk?, Petr
%A Hlinomazov?, Zuzana
%A Balcar, Vladimir J
%T Association between Val66Met polymorphism of Brain-Derived Neurotrophic Factor (BDNF) gene and a deficiency of colour vision in alcohol-dependent male patients.
%B Neuroscience Letters
%D 2011
%V 499
%N 3
%P 154-7
%@ 1872-7972
%X Brain-derived neurotrophic factor (BDNF) is a protein encoded, in humans, by BDNF gene on chromosome 11. BDNF protects adult neurons and promotes growth and differentiation during ontogenetic development but the nature and magnitude of its effects could be influenced by functional polymorphisms. The BDNF polymorphism Val66Met (rs6265) has been studied in the context of etiology of mental diseases including alcoholism. Alcoholism - a complex disorder known to be linked to several genes - has multiple manifestations, including sensory deficits such as those affecting vision. In the present study we examined a relationship between the Val66Met polymorphism, alcohol dependence and colour vision deficiency (CVD) in 167 alcohol-dependent men and 289 control male subjects. Statistical analysis revealed that almost half (about 48%) of the alcohol dependent men had a CVD. In addition we found that CVD was significantly associated (P=0.005) with the Val66Met polymorphism. The A allele containing 66Met promotes BDNF expression and this may protect humans against CVD induced by long-term excessive alcohol intake. The present findings indicate that alcohol-induced CVD does not depend solely on excessive alcohol consumption but is significantly influenced by genetic predisposition in the form of a specific BDNF polymorphism.
%Z FOR Codes: 110902



%0 Journal Article
%~ Pubmed
%A Nasrallah, Fatima A
%A Maher, Anthony D
%A Hanrahan, Jane R
%A Balcar, Vladimir J
%A Rae, Caroline D
%T ??-Hydroxybutyrate and the GABAergic footprint: a metabolomic approach to unpicking the actions of GHB.
%B Journal of Neurochemistry
%D 2010
%V 115
%N 1
%P 58-67
%@ 1471-4159
%X J. Neurochem. (2010) 115, 58-67. ABSTRACT: Gamma-hydroxybutyrate is found both naturally in the brain and self-administered as a drug of abuse. It has been reported to act at endogenous ??-hydroxybutyrate (GHB) receptors and GABA(B) receptors [GABA(B)R], and may also be metabolized to GABA. Here, the metabolic fingerprints of a range of concentrations of GHB were measured in brain cortical tissue slices and compared with those of ligands active at GHB and GABA-R using principal components analysis (PCA) to identify sites of GHB activity. Low concentrations of GHB (1.0?????M) produced fingerprints similar to those of ligands active at GHB receptors and ??4-containing GABA(A)R. A total of 10?????M GHB clustered proximate to mainstream GABAergic synapse ligands, such as 1.0?????M baclofen, a GABA(B)R agonist. Higher concentrations of GHB (30?????M) clustered with GABA(C)R agonists and the metabolic responses induced by blockade of the GABA transporter-1 (GAT1). The metabolic responses induced by 60 and 100?????M GHB were mimicked by simultaneous blockade of GAT1 and GAT3, addition of low concentrations of GABA(C)R antagonists, or increasing cytoplasmic GABA concentrations by incubation with the GABA transaminase inhibitor vigabatrin. These data suggest that at concentrations >???30?????M, GHB may be active via metabolism to GABA, which is then acting upon an unidentified GABAergic master switch receptor (possibly a high-affinity extrasynaptic receptor), or GHB may itself be acting directly on an extrasynaptic GABA-R, capable of turning off large numbers of cells. These results offer an explanation for the steep dose-response curve of GHB seen in vivo, and suggest potential target receptors for further investigation.
%Z FOR Codes: 110903 110903



%0 Journal Article
%~ Pubmed
%A Nguyen, Khoa T D
%A Buljan, Vlado
%A Else, Paul L
%A Pow, David V
%A Balcar, Vladimir J
%T Cardiac glycosides ouabain and digoxin interfere with the regulation of glutamate transporter GLAST in astrocytes cultured from neonatal rat brain.
%B Neurochemical research
%D 2010
%V 35
%N 12
%P 2062-9
%@ 1573-6903
%X Glutamate transport (GluT) in brain is mediated chiefly by two transporters GLT and GLAST, both driven by ionic gradients generated by (Na(+), K(+))-dependent ATPase (Na(+)/K(+)-ATPase). GLAST is located in astrocytes and its function is regulated by translocations from cytoplasm to plasma membrane in the presence of GluT substrates. The phenomenon is blocked by a naturally occurring toxin rottlerin. We have recently suggested that rottlerin acts by inhibiting Na(+)/K(+)-ATPase. We now report that Na(+)/K(+)-ATPase inhibitors digoxin and ouabain also blocked the redistribution of GLAST in cultured astrocytes, however, neither of the compounds caused detectable inhibition of ATPase activity in cell-free astrocyte homogenates (rottlerin inhibited app. 80% of Pi production from ATP in the astrocyte homogenates, IC50 = 25 ??M). Therefore, while we may not have established a direct link between GLAST regulation and Na(+)/K(+)-ATPase activity we have shown that both ouabain and digoxin can interfere with GluT transport and therefore should be considered potentially neurotoxic.
%Z FOR Codes: 1109



%0 Journal Article
%A Nasrallah, Fatima A
%A Balcar, Vladimir
%A Rae, Caroline
%T A metabonomic study of inhibition of GABA uptake in the cerebral cortex
%B Metabolomics
%D 2010
%C United States
%I Springer New York LLC
%V 6
%N 
%P 66-67
%@ 1573-3882
%X 
%Z FOR Codes: 110904



%0 Journal Article
%~ Pubmed
%A Shin, Jae-Won
%A Nguyen, Khoa
%A Pow, David
%A Knight, Toby
%A Buljan, Vlado
%A Bennett, Maxwell
%A Balcar, Vladimir
%T Distribution of glutamate transporter GLAST in membranes of cultured astrocytes in the presence of glutamate transport substrates and ATP.
%B Neurochemical research
%D 2009
%V 34
%N 10
%P 1758-66
%@ 1573-6903
%X Neurotransmitter L-glutamate released at central synapses is taken up and "recycled" by astrocytes using glutamate transporter molecules such as GLAST and GLT. Glutamate transport is essential for prevention of glutamate neurotoxicity, it is a key regulator of neurotransmitter metabolism and may contribute to mechanisms through which neurons and glia communicate with each other. Using immunocytochemistry and image analysis we have found that extracellular D-aspartate (a typical substrate for glutamate transport) can cause redistribution of GLAST from cytoplasm to the cell membrane. The process appears to involve phosphorylation/dephosphorylation and requires intact cytoskeleton. Glutamate transport ligands L-trans-pyrrolidine-2,4-dicarboxylate and DL-threo-3-benzyloxyaspartate but not anti,endo-3,4-methanopyrrolidine dicarboxylate have produced similar redistribution of GLAST. Several representative ligands for glutamate receptors whether of ionotropic or metabotropic type, were found to have no effect. In addition, extracellular ATP induced formation of GLAST clusters in the cell membranes by a process apparently mediated by P2 receptors. The present data suggest that GLAST can rapidly and specifically respond to changes in the cellular environment thus potentially helping to fine-tune the functions of astrocytes.
%Z FOR Codes: 60105



%0 Journal Article
%~ Pubmed
%A Rae, Caroline
%A Nasrallah, Fatima A
%A Griffin, Julian L
%A Balcar, Vladimir J
%T Now I know my ABC. A systems neurochemistry and functional metabolomic approach to understanding the GABAergic system.
%B Journal of Neurochemistry
%D 2009
%V 109 Suppl 1
%N 
%P 109-16
%@ 1471-4159
%X Here, we describe use of a reductionist brain model, the brain tissue slice, to generate snapshots of functional metabolism in response to a pharmacological (GABAergic) perturbation. Tissue slices prepared from Guinea pig cerebral cortex were incubated for 1 h in the presence of [3-13C]-pyruvate and ligands with affinity for GABA receptors. The resultant patterns of 13C flux and metabolite levels were measured by 13C/1H NMR spectroscopy, generating 'metabolic fingerprints' for each ligand. Effects of agonists and effectors at GABA receptors (A, B, and C types) were examined, compared to those of exogenous GABA and evaluated using multivariate statistical models. Data clusterings did not directly correlate with GABA receptor types but produced at least five distinct groups ranked according to their affinity for GABA. As our experimental model retains, to a large extent, the structure and function of normal brain tissue, the generated database can be used to assess GABAergic ligands and make unique inferences relevant to their modes of action in brain.
%Z FOR Codes: 60105



%0 Journal Article
%~ Pubmed
%A Nasrallah, Fatima A
%A Griffin, Julian L
%A Balcar, Vladimir J
%A Rae, Caroline
%T Understanding your inhibitions: effects of GABA and GABAA receptor modulation on brain cortical metabolism.
%B Journal of Neurochemistry
%D 2009
%V 108
%N 1
%P 57-71
%@ 1471-4159
%X A targeted neuropharmacological, (1)H/(13)C NMR spectroscopy and multivariate statistical approach was used to examine the effects of exogenous GABA and ligands at the GABA(A) receptor family on brain metabolism in the Guinea pig cortical tissue slice. All ligands at GABA(A) receptors generated metabolic patterns which were distinct from one another with the major variance in the data arising because of metabolic work (shown by net flux into Krebs cycle byproducts and increased metabolic pool sizes). Three major clusters of metabolic signatures were identified which corresponded to: (i) activity at phasic (synaptic) GABA(A) receptors, dominated by alpha1-containing receptors and responsive to GABA at 10 micromol/L; (ii) activity at perisynaptic receptors, dominated by response to high (40 micromol/L) GABA and the superagonist 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-3-ol hydrochloride, and C, activity at extrasynaptic receptors, dominated by response to low (0.1-1.0 micromol/L) GABA, zolpidem (400 nmol/L) and the non-specific allosteric modulator RO19-4603 (1 nmol/L). These results highlight the utility of a different but robust approach to study of the GABAergic system using metabolic systems analysis.
%Z FOR Codes: 110999



%0 Journal Article
%A Beart, P M
%A Balcar, Vladimir
%T Graham Johnston: bringing success to neuroscience through medicinal chemistry.
%B Neurochemical Research
%D 2009
%C United States
%I Springer
%V 34
%N 
%P 1696-1697
%@ 0364-3190
%X 
%Z FOR Codes: 110999



%0 Journal Article
%~ Pubmed
%A Nguyen, Khoa
%A Shin, Jae-Won
%A Rae, Caroline
%A Nanitsos, Ellas
%A Acosta, Gabriela
%A Pow, David
%A Buljan, Vlado
%A Bennett, Maxwell
%A Else, Paul
%A Balcar, Vladimir
%T Rottlerin inhibits (Na+, K+)-ATPase activity in brain tissue and alters D-aspartate dependent redistribution of glutamate transporter GLAST in cultured astrocytes.
%B Neurochemical research
%D 2009
%V 34
%N 10
%P 1767-74
%@ 1573-6903
%X The naturally occurring toxin rottlerin has been used by other laboratories as a specific inhibitor of protein kinase C-delta (PKC-delta) to obtain evidence that the activity-dependent distribution of glutamate transporter GLAST is regulated by PKC-delta mediated phosphorylation. Using immunofluorescence labelling for GLAST and deconvolution microscopy we have observed that D-aspartate-induced redistribution of GLAST towards the plasma membranes of cultured astrocytes was abolished by rottlerin. In brain tissue in vitro, rottlerin reduced apparent activity of (Na+, K+)-dependent ATPase (Na+, K+-ATPase) and increased oxygen consumption in accordance with its known activity as an uncoupler of oxidative phosphorylation ("metabolic poison"). Rottlerin also inhibited Na+, K+-ATPase in cultured astrocytes. As the glutamate transport critically depends on energy metabolism and on the activity of Na+, K+-ATPase in particular, we suggest that the metabolic toxicity of rottlerin and/or the decreased activity of the Na+, K+-ATPase could explain both the glutamate transport inhibition and altered GLAST distribution caused by rottlerin even without any involvement of PKC-delta-catalysed phosphorylation in the process.
%Z FOR Codes: 60105



%0 Journal Article
%~ Pubmed
%A Getts, Daniel R
%A Balcar, Vladimir J
%A Matsumoto, Izuru
%A M?ller, Marcus
%A King, Nicholas J C
%T Viruses and the immune system: their roles in seizure cascade development.
%B Journal of Neurochemistry
%D 2008
%V 104
%N 5
%P 1167-76
%@ 1471-4159
%X Viral encephalitis affects approximately 7.5 people/100 000 and carries a high rate of morbidity and mortality. Most patients with viral encephalitis will develop some form of seizure during the infectious process, and of those who survive encephalitic disease, approximately 4-20% will develop epilepsy. Arthropod-borne (arbo)viruses are the leading cause of viral encephalitis in the world today, with between 10% and 35% of patients infected with these viruses displaying some form of seizure. Several neurotropic DNA viruses, including Herpes and cytomegalovirus also commonly cause seizures in infected patients. In the clinical setting, the cause of seizures seen during viral encephalitis is usually attributed to acute febrile responses. However, it has become apparent that the mechanisms behind seizure generation during viral encephalitis are likely to be much more complicated. For example, CD4(+) and CD8(+) T cells possibly through their secretion of interferon-gamma, appear to play an important role in determining neuronal responses when challenged with kainic acid. In addition, the ability of the human immunodeficiency virus, transactivating protein to modulate NMDA signaling possibly triggering seizures, highlights the fact that elements of the antiviral response and even virally derived proteins are capable of directly manipulating neuronal function. Understanding the complex relationships between the CNS, the immune system, and invading pathogens is a critical step in understanding the pathogenesis of seizures seen during viral infections and informing the development of novel therapies.
%Z FOR Codes: 110804 110903 110704



%0 Journal Article
%~ Pubmed
%A Br?er, Stefan
%A Br?er, Angelika
%A Hansen, Jonas T
%A Bubb, William A
%A Balcar, Vladimir J
%A Nasrallah, Fatima A
%A Garner, Brett
%A Rae, Caroline
%T Alanine metabolism, transport, and cycling in the brain.
%B Journal of Neurochemistry
%D 2007
%V 102
%N 6
%P 1758-70
%@ 0022-3042
%X Brain glutamate/glutamine cycling is incomplete without return of ammonia to glial cells. Previous studies suggest that alanine is an important carrier for ammonia transfer. In this study, we investigated alanine transport and metabolism in Guinea pig brain cortical tissue slices and prisms, in primary cultures of neurons and astrocytes, and in synaptosomes. Alanine uptake into astrocytes was largely mediated by system L isoform LAT2, whereas alanine uptake into neurons was mediated by Na(+)-dependent transporters with properties similar to system B(0) isoform B(0)AT2. To investigate the role of alanine transport in metabolism, its uptake was inhibited in cortical tissue slices under depolarizing conditions using the system L transport inhibitors 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid and cycloleucine (1-aminocyclopentanecarboxylic acid; cLeu). The results indicated that alanine cycling occurs subsequent to glutamate/glutamine cycling and that a significant proportion of cycling occurs via amino acid transport system L. Our results show that system L isoform LAT2 is critical for alanine uptake into astrocytes. However, alanine does not provide any significant carbon for energy or neurotransmitter metabolism under the conditions studied.



%0 Journal Article
%~ Pubmed
%A Nasrallah, Fatima A
%A Griffin, Julian L
%A Balcar, Vladimir J
%A Rae, Caroline
%T Understanding your inhibitions: modulation of brain cortical metabolism by GABA(B) receptors.
%B Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
%D 2007
%V 27
%N 8
%P 1510-20
%@ 0271-678X
%X Although the impact of neuronal excitation on the functional activity of brain is well understood, the nature of functional responses to inhibitory modulation is far from clear. In this work, we investigated the effects of modulation of the metabotropic GABA(B) receptor on brain metabolism using a targeted neuropharmacological, (1)H/(13)C nuclear magnetic resonance spectroscopy, and metabolomic approach. While agonists at GABA(B) receptors (Baclofen and SKF 97541) generally decreased metabolic activity, mild agonist action could also stimulate metabolism. Less potent antagonists (CGP 35348, Phaclofen) significantly decreased metabolic activity, while more potent antagonists (CGP 52432 and SCH 50911) had opposite, stimulatory, effects. Examination of the data by principal components analysis showed clear divisions of the effects into excitatory and inhibitory components. GABAergic modulation can, therefore, have stimulatory, inhibitory, or even neutral net effects on metabolic activity in brain tissue. This is consistent with GABAergic activity being context dependent, and this conclusion should be taken into account when evaluating functional imaging data involving modulation of neuronal inhibition.
%Z FOR Codes: 110903 110101 110502



%0 Journal Article
%~ Pubmed
%A Moussa, Charbel E-H
%A Rae, Caroline
%A Bubb, William A
%A Griffin, Julian L
%A Deters, Natasha A
%A Balcar, Vladimir J
%T Inhibitors of glutamate transport modulate distinct patterns in brain metabolism.
%B Journal of neuroscience research
%D 2006
%V 85
%N 2
%P 342-50
%@ 0360-4012
%X High affinity uptake of glutamate plays a major role in the termination of excitatory neurotransmission. Identification of the ramifications of transporter function is essential to understand the diseases in which defective excitatory amino acid transporters (EAAT) have been implicated. In this work we incubated Guinea pig cortical tissue slices with [3-(13)C]pyruvate and major currently available glutamate uptake inhibitors and studied the resultant metabolic sequelae by (13)C and (1)H NMR spectroscopy using a multivariate statistical approach. Perturbation of glutamate uptake produced significant effects on metabolic flux through the Krebs cycle, and on glutamate/glutamine cycling rates, with this effect accounting for 76% of the variation in the total data set. The effects of all inhibitors were separable from each other along three major principal components. The competitive inhibitor L-CCG III ((2S,1'S,2'R)-2-carboxycyclopropyl)glycine) differed most from the other inhibitors, showing negative weightings on both the first and second principal components, whereas the EAAT2-specific inhibitor dihydrokainate (DHK) showed metabolic patterns similar to that of anti-endo-3,4-methanopyrolidine dicarboxylate but separate from those of DL-threo-beta-benzyloxyaspartate (TBOA) and L-trans-pyrrolidine-2,4-dicarboxylate (L-tPDC). This indicates that different inhibition mechanisms or different colocalisation of the separate transporter subtypes with glutamate receptors can produce significantly different metabolic and functional outcomes for the brain.
%Z FOR Codes: 110902 111505



%0 Journal Article
%~ Isi
%A Kaiser, M.
%A Mares, V.
%A Stastny, F.
%A Bubenikova-Valesova, V.
%A Lisa, V.
%A Suchomel, P.
%A Balcar, V. J.
%T The influence of interleukin-1 beta on gamma-glutamyl transpeptidase activity in rat hippocampus.
%B Physiological Research
%D 2006
%C Czech Republic
%I Akademie Ved Ceske Republiky
%V 55
%N 4
%P 461-465
%@ 0862-8408
%X 
%Z FOR Codes: 110903



%0 Journal Article
%~ Isi
%A Bubenikova-Valesova, V.
%A Balcar, V. J.
%A Tejkalova, H.
%A Langmeier, M.
%A St'astny, F.
%T Neonatal administration of N-acetyl-L-aspartyl-L-glutamate induces early neurodegeneration in hippocampus and alters behaviour in young adult rats.
%B Neurochemistry International
%D 2006
%C UK
%I Elsevier Ltd
%V 48
%N 6-7
%P 515-522
%@ 0197-0186
%X 
%Z FOR Codes: 110903



%0 Journal Article
%~ Isi
%A Balcar, V. J.
%A Nanitsos, E. K.
%T Autoradiography of H-3 aspartate and glutamate transport in chizophrenia.
%B Neuropsychopharmacology
%D 2006
%C UK, US
%I Nature Publishing Group
%V 31
%N 3
%P 685-686
%@ 0893-133X
%X 
%Z FOR Codes: 110903



%0 Journal Article
%A Stastny, F
%A Vrajov?, M
%A Tejkalova, H
%A Pekov?, S
%A Mare?, V
%A Kozmikov?, I
%A Jir?skov?, J
%A H?schl, C
%A Balcar, Vladimir
%T Composition and function of NMDA receptors in schizophrenia: from animal models to patients
%B Psychiatrie
%D 2006
%C Czech Republic
%I Tigis s. r. o.
%V 6
%N Suppl2
%P 7-14
%@ 1211-7579
%X 
%Z FOR Codes: 170101



%0 Journal Article
%~ Pubmed
%A Rae, Caroline
%A Moussa, Charbel El-Hajj
%A Griffin, Julian L
%A Bubb, William A
%A Wallis, Trent
%A Balcar, Vladimir J
%T Group I and II metabotropic glutamate receptors alter brain cortical metabolic and glutamate/glutamine cycle activity: a 13C NMR spectroscopy and metabolomic study.
%B Journal of Neurochemistry
%D 2005
%V 92
%N 2
%P 405-16
%@ 0022-3042
%X Metabotropic glutamate receptors (mGluR) modulate neuronal function. Here, we tested the effect on metabolism of a range of Group I and II mGluR ligands in Guinea pig brain cortical tissue slices, applying 13C NMR spectroscopy and metabolomic analysis using multivariate statistics. The effects of Group I agonists (S)-3,5-dihydroxyphenylglycine (DHPG) and (RS)-2-chloro-5-hydroxyphenylglycine (CHPG) depended upon concentration and were mostly stimulatory, increasing both net metabolic flux through the Krebs cycle and glutamate/glutamine cycle activity. Only the higher (50 microm) concentrations of CHPG had the opposite effect. The Group I antagonist (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA), consistent with its neuroprotective role, caused significant decreases in metabolism. With principal components analysis of the metabolic profiles generated by these ligands, the effects could be separated by two principal components. Agonists at Group II mGluR [(2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG IV) and 2R,4R-4-aminopyrrolidine-2,4-dicarboxylate (APDC)] generally stimulated metabolism, including glutamate/glutamine cycling, although this varied with concentration. The antagonist (2S)-alpha-ethylglutamic acid (EGLU) stimulated astrocyte metabolism with minimal impact on glutamate/glutamine cycling. (RS)-1-Aminophosphoindan-1-carboxylic acid (APICA) decreased metabolism at 5 microm but had a stimulatory effect at 50 microm. All ligand effects were separated from control and from each other using two principal components. The ramifications of these findings are discussed.
%Z FOR Codes: 110902



%0 Journal Article
%~ Pubmed
%A Nanitsos, Ellas K
%A Nguyen, Khoa T D
%A St'astn?, Frantisek
%A Balcar, Vladimir J
%T Glutamatergic hypothesis of schizophrenia: involvement of Na(+)/K(+)-dependent glutamate transport.
%B Journal of biomedical science
%D 2005
%V 12
%N 6
%P 975-84
%@ 1021-7770
%X Hypothetical model based on deficient glutamatergic neurotransmission caused by hyperactive glutamate transport in astrocytes surrounding excitatory synapses in the prefrontal cortex is examined in relation to the aetiology of schizophrenia. The model is consistent with actions of neuroleptics, such as clozapine, in animal experiments and it is strongly supported by recent findings of increased expression of glutamate transporter GLT in prefrontal cortex of patients with schizophrenia. It is proposed that mechanisms regulating glutamate transport be investigated as potential targets for novel classes of neuroactive compounds with neuroleptic characteristics. Development of new efficient techniques designed specifically for the purpose of studying rapid activity-dependent translocation of glutamate transporters and associated molecules such as Na(+), K(+)-ATPase is essential and should be encouraged.
%Z FOR Codes: 110999



%0 Journal Article
%~ Pubmed
%A Kaiser, M
%A Mare?, V
%A S?astn?, F
%A Buben?kov?, V
%A Lis?, V
%A Suchomel, P
%A Balcar, V
%T The influence of interleukin-1beta on gamma-glutamyl transpepidase activity in rat hippocampus.
%B Physiological research / Academia Scientiarum Bohemoslovaca
%D 2005
%V 55
%N 4
%P 461-5
%@ 0862-8408
%X Brain infections as well as peripheral challenges to the immune system lead to an increased production of interleukin-1beta (IL-1beta), a cytokine involved in leukocyte-mediated breakdown of the blood-brain barrier. The effects of IL-1beta have been reported to depend on whether the route of administration is systemic or intracerebral. Using 50-day-old male rats, we compared the effects of IL-1beta on brain gamma-glutamyl transpeptidase (GGT; an enzymatic marker of brain capillary endothelium) at 2, 24 and 96 h after either an intravenous (i.v.) injection of 5 microg IL-1beta or an intracerebroventricular (i.c.v. - lateral ventricle) infusion of 50 ng IL-1beta. When the i.v. route was used, the GGT activity underwent small but significant changes; decreasing in the hippocampus 2 h after the i.v. injection, increasing 24 h later and returning to control levels at 96 h. No significant changes in the hippocampal GGT activity were observed at 2 and 24 h following the i.c.v. infusion. The GGT activity in the hypothalamus remained unchanged regardless of the route of IL-1beta administrations. Similar changes in GGT activity were revealed histochemically. The labeling was found mainly in the capillary bed, the changes being most evident in the hippocampal stratum radiatum and stratum lacunosum-moleculare. A transient increase in GGT activity at 24 h, together with a less sharp delineation of GGT-stained vessels, may reflect IL-1beta induced increased turnover of glutathione and/or oxidative stress, that may in turn, be related to altered permeability of the blood-brain barrier in some neurological and mental disorders, including schizophrenia.
%Z FOR Codes: 110903



%0 Journal Article
%~ Pubmed
%A Rae, Caroline
%A Moussa, Charbel El-Hajj
%A Griffin, Julian L
%A Parekh, Sapan B
%A Bubb, William A
%A Hunt, Nicholas H
%A Balcar, Vladimir J
%T A metabolomic approach to ionotropic glutamate receptor subtype function: a nuclear magnetic resonance in vitro investigation.
%B Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
%D 2005
%V 26
%N 8
%P 1005-17
%@ 0271-678X
%X A range of behaviours are elucidated via ionotropic glutamate receptors (iGluR). In this work, we examined the acute activation of iGluRs by a range of receptor ligands and effectors to see whether distinguishable metabolic sequelae were elucidated by the activity. We used a guinea-pig brain cortical tissue slice model using targeted receptor ligands ((RS)-(tetrazol-5-yl)glycine (TZG), (5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate (MK-801, dizocilpine), cis-4-[phosphomethyl]-piperidine-2-carboxylic acid (CGS 19755), (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, (2S, 3S, 4S)-2-carboxy-4-(1-methylethenyl)-3-pyrrolidineacetic acid (kainate) and D-serine (D-Ser), as well as compounds (quinolinic acid and kynurenic acid (KynA)) involved in some neuroinflammatory responses. The data were derived using 13C and 1H NMR spectroscopy, and analysed by metabolomic approaches and multivariate statistics. The metabolic effects of agonists at the three major classes of iGluR were easily separated from each other using this method. The classical N-methyl-D-aspartate receptor agonist TZG and the antagonist CGS 19755 produced excitatory and inhibitory metabolic responses, respectively, while the blocker MK-801 resulted in a significant decrease in net metabolism and produced the largest decrease in all metabolite pool sizes seen by any glutamatergic ligand we have studied. Quinolinic acid and KynA produced similar acute metabolic responses, which were unlike those to TZG or CGS 19755, but similar to that of D-Ser. D-Ser was highly stimulatory of net flux into the Krebs cycle. These data show that the metabolic response to iGluR perturbation in vitro is a sensitive discriminator of function.
%Z FOR Codes: 110902



%0 Journal Article
%~ Isi
%A Parekh, S. B.
%A Moussa, C. E.
%A Balcar, V. J.
%A Hunt, N. H.
%A Bubb, W. A.
%A Rae, C.
%T Quinolinic acid, kynurenic acid and dserine stimulate brain metabolism.
%B Journal of Neurochemistry
%D 2005
%C United Kingdom
%I Blackwell Publishing Ltd.
%V 94
%N 
%P 58-58
%@ 0022-3042
%X 
%Z FOR Codes: 110902



%0 Journal Article
%~ Pubmed
%A Kuramoto, Nobuyuki
%A Kubo, Keita
%A Ogita, Kiyokazu
%A Pl?ten?k, Jan
%A Balcar, Vladimir J
%A Takarada, Takeshi
%A Nakamichi, Noritaka
%A Yoneda, Yukio
%T Nuclear condensation of cyclic adenosine monophosphate responsive element-binding protein in discrete murine brain structures.
%B Journal of neuroscience research
%D 2005
%V 80
%N 5
%P 667-76
%@ 0360-4012
%X We have directed a polyclonal antibody against an oligo-peptide (123-136) of the transcription factor cyclic AMP responsive element-binding protein (CREB) including the serine residue at 133. Rabbit sera were purified by ammonium sulfate precipitation, followed by affinity chromatography to homogeneity on one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified antibody not only induced marked supershift of CREB binding, without affecting binding of activator protein-1 on gel retardation electrophoresis, but also differentiated between CREB and CREB phosphorylated at serine133 in brain nuclear fractions on Western blotting. Immunoreactive CREB was detected in both cytosolic and nuclear fractions of discrete murine brain structures but was more highly condensed in cerebellum than in neocortex and hippocampus. Incubation of brain nuclear fractions led to a marked export of immunoreactive CREB in a temperature-dependent manner, whereas the temperature-dependent export activity was significantly lower in cerebellum than in other brain structures. Suppression of general new protein synthesis by cycloheximide (500 mg/kg, i.p.) in vivo resulted in a significant decrease in the nuclear CREB level, with a concomitant increase in the cytosolic level in hippocampus, but not in cerebellum. These results suggest that the nuclear export activity might vary from region to region in murine brains through a hitherto unidentified mechanism other than the nuclear localization signal, to result in different nuclear condensation ratios for subsequent elicitation of differential transcriptional activities by the constitutive transcription factor CREB in the nucleus.
%Z FOR Codes: 110903



%0 Journal Article
%~ Pubmed
%A Pl?ten?k, Jan
%A Balcar, Vladim?r J
%A Yoneda, Yukio
%A Mioduszewska, Barbara
%A Buchal, Richard
%A Hynek, Radovan
%A Kilianek, Lukasz
%A Kuramoto, Nobuyuki
%A Wilczynski, Grzegorz
%A Ogita, Kiyokazu
%A Nakamura, Yoichi
%A Kaczmarek, Leszek
%T Apparent presence of Ser133-phosphorylated cyclic AMP response element binding protein (pCREB) in brain mitochondria is due to cross-reactivity of pCREB antibodies with pyruvate dehydrogenase.
%B Journal of Neurochemistry
%D 2005
%V 95
%N 5
%P 1446-60
%@ 0022-3042
%X Cyclic AMP response element binding protein (CREB) is a constitutive transcription factor that activates transcription following stimulus-dependent phosphorylation at Ser133, implicated in synaptic plasticity and neuronal survival pathways. The prevailing view that CREB is exclusively nuclear has been questioned by several studies, and, for example, mitochondrial localization has been reported. Using subcellular fractionation of rat brain cortex coupled with western immunoblotting with Ser133-phospho-CREB (pCREB) antibodies, we found a robust pCREB immunoreactivity (IR) in mitochondria-enriched fractions. The pCREB antibodies also stained the mitochondria, in addition to nuclei, of glial cells in primary cortical cultures. However, two CREB antibodies against different epitopes and gel shift assay detected the CREB protein mainly in the nuclear fraction. The two-dimensional electrophoretic mobility of mitochondrial pCREB IR differed markedly from the nuclear CREB/pCREB IR, indicating that the pCREB antibody cross-reacts with another mitochondrial protein. Immunoprecipitation of the mitochondrial pCREB IR produced three bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as E2, E1 alpha-subunit, and E1 beta-subunit of pyruvate dehydrogenase complex. The cross-reacting epitope was identified as phospho-Ser300 of the alpha-subunit. In conclusion, this study confirms the presence of pCREB-like IR in brain mitochondria that, after careful scrutiny, turned out to be pyruvate dehydrogenase rather than authentic CREB.
%Z FOR Codes: 110903



%0 Journal Article
%A Balcar, Vladimir
%A Nanitsos, EK
%T Glutamate transport - target for the next generation of neuroleptics?
%B Psychiatrie
%D 2005
%C Czech Republic
%I Tigis s. r. o.
%V 9: Suppl2
%N 
%P 19-23
%@ 
%X 
%Z FOR Codes: 110106



%0 Journal Article
%~ Pubmed
%A Wallis, Trent
%A Bubb, William A
%A McQuillan, James A
%A Balcar, Vladimir J
%A Rae, Caroline
%T For want of a nail. ramifications of a single gene deletion, dystrophin, in the brain of the mouse.
%B Frontiers in bioscience : a journal and virtual library
%D 2004
%V 9
%N 
%P 74-84
%@ 1093-4715
%X Lack of expression of a single gene, dystrophin, causes the severe, progressive muscle wasting and mental deficits characteristic of Duchenne muscular dystrophy. In this work, we investigated the impact of dystrophin deletion on expression of other genes in the brain cortex, hippocampus and cerebellum using the murine homologue, the mdx mouse, and RT-PCR. Expression of the brain glucose transporters GLUT1 and GLUT2 was found to be decreased, as were some subunits of the GABAA and nicotinic acetylcholine receptors. Genes involved in bioenergetic homeostasis, such as the mitochondrial creatine kinase and the gamma subunit of ATP synthase were also found to be abnormally expressed, while expression of the structural proteins beta-dystrobrevin and rapsyn was also significantly affected. We relate these findings to known functional deficits and discuss the possible mechanisms behind the altered gene expression.



%0 Journal Article
%~ Pubmed
%A Nanitsos, Ellas K
%A Acosta, Gabriela B
%A Saihara, Yukiko
%A Stanton, David
%A Liao, Lee P
%A Shin, Jae W
%A Rae, Caroline
%A Balcar, Vladimir J
%T Effects of glutamate transport substrates and glutamate receptor ligands on the activity of Na-/K(+)-ATPase in brain tissue in vitro.
%B Clinical and Experimental Pharmacology & Physiology
%D 2004
%V 31
%N 11
%P 762-9
%@ 0305-1870
%X 1. It has been suggested that Na+/K(+)-ATPase and Na(+)-dependent glutamate transport (GluT) are tightly linked in brain tissue. In the present study, we have investigated Na+/K(+)-ATPase activity using Rb+ uptake by 'minislices' (prisms) of the cerebral cortex. This preparation preserves the morphology of neurons, synapses and astrocytes and is known to possess potent GluT that has been well characterized. Uptake of Rb+ was determined by estimating Rb+ in aqueous extracts of the minislices, using atomic absorption spectroscopy. 2. We determined the potencies of several known substrates/inhibitors of GluT, such as L-trans-pyrrolidine-2,4-dicarboxylate (LtPDC), DL-threo-3-benzyloxyaspartic acid, (2S,3S,4R)-2-(carboxycyclopropyl)-glycine (L-CCG III) and L-anti,endo-3,4-methanopyrrolidine dicarboxylic acid, as inhibitors of [3H]-L-glutamate uptake by cortical prisms. In addition, we established the susceptibility of GluT, measured as [3H]-L-glutamate uptake in brain cortical prisms, to the inhibition of Na+/K(+)-ATPase by ouabain. Then, we tested the hypothesis that the Na+/K(+)-ATPase (measured as Rb+ uptake) can respond to changes in the activity of GluT produced by using GluT substrates as GluT-specific pharmacological tools. 3. The Na+/K(+)-ATPase inhibitor ouabain completely blocked Rb+ uptake (IC50 = 17 micromol/L), but it also potently inhibited a fraction of GluT (approximately 50% of [3H]-L-glutamate uptake was eliminated; IC50 < 1 micromol/L). 4. None of the most commonly used GluT substrates and inhibitors, such as L-aspartate, D-aspartate, L-CCG III and LtPDC (all at 500 micromol/L), produced any significant changes in Rb+ uptake. 5. The N-methyl-D-aspartate (NMDA) receptor agonists (R,S)-(tetrazol-5-yl)-glycine and NMDA decreased Rb+ uptake in a manner compatible with their known neurotoxic actions. 6. None of the agonists or antagonists for any of the other major classes of glutamate receptors caused significant changes in Rb+ uptake. 7. We conclude that, even if a subpopulation of glutamate transporters in the rat cerebral cortex may be intimately linked to a fraction of Na+/K(+)-ATPase, it is not possible, under the present experimental conditions, to detect regulation of Na+/K(+)-ATPase by GluT.



%0 Journal Article
%~ Pubmed
%A St'astn?, Frantisek
%A Lis?, V?clav
%A Mares, Vladislav
%A Lis?, Vera
%A Balcar, Vladimir J
%A Santamar?a, Abel
%T Quinolinic acid induces NMDA receptor-mediated lipid peroxidation in rat brain microvessels.
%B Redox report : communications in free radical research
%D 2004
%V 9
%N 4
%P 229-33
%@ 1351-0002
%X Quinolinic acid increased the generation of lipid peroxidation products by isolated rat brain microvessels in vitro. The effect was inhibited both by a specific NMDA receptor antagonist D-2-amino-5-phosphonovaleric acid and by reduced glutathione (GSH). Furthermore, quinolinic acid displaced specific binding of [(3)H]-L-glutamate by cerebral microvessel membranes, particularly in the presence of NMDA receptor co-agonist (glycine) and modulator (spermidine). We conclude that quinolinic acid can cause potentially cytotoxic lipid peroxidation in brain microvessels via an NMDA receptor mediated mechanism.



%0 Journal Article
%~ Pubmed
%A Takarada, T
%A Hinoi, E
%A Balcar, V J
%A Taniura, H
%A Yoneda, Y
%T Possible expression of functional glutamate transporters in the rat testis.
%B The Journal of endocrinology
%D 2004
%V 181
%N 2
%P 233-44
%@ 0022-0795
%X Neither expression nor functionality is clear in peripheral tissues with the molecular machineries required for excitatory neurotransmitter signaling by L-glutamate (Glu) in the central nervous system, while a recent study has shown that several Glu receptors are functionally expressed in the rat testis. This fact prompted us to explore the possible functional expression in the rat testis of the Glu transporters usually responsible for the regulation of extracellular Glu concentrations in the brain. RT-PCR revealed the expression, in the rat testis, of mRNA for five different subtypes of Glu transporters, in addition to that for particular subtypes of ionotropic and metabotropic Glu receptors. Glutamate transporter-1 (GLT-1) was different in the brain from that in the testis in terms of molecular sizes on Northern and Western blot analyses. In situ hybridization as well as immunohistochemical analysis showed localized expression of glutamate aspartate transporter at interstitial spaces and GLT-1 at elongated spermatids in the rat testis respectively. The expression of mRNA was localized for excitatory amino acid transporter-5 at the basal compartment of the seminiferous tubule in the rat testis. [(3)H]Glu was accumulated in testicular crude mitochondrial fractions in a temperature- and sodium-dependent saturable manner with pharmacological profiles similar to those shown in brain crude mitochondrial fractions. These results suggested that particular subtypes of central Glu transporters for the regulation of extracellular Glu concentrations in the rat testis could be constitutively and functionally expressed.



%0 Journal Article
%A Balcar, Vladimir
%A Stastny, Frantisek
%A Tejkalova, Hana
%A Skuba, Irina
%A Palenicek, Tomas
%A Pliss, Lioudmila
%A Mares, Vladislav
%A Kristofikova, Zdena
%A Kaiser, Miroslav
%A Bubenikova, Vera
%A Balcar, Vladimir
%T Interactions of Dopamine D1/D2 Receptor with Glutamate Receptor of NMDA type: from Molecules to Animal Models of Schizophrenia (in Czech)
%B Psychiatrie (Prague)
%D 2004
%C Prague
%I Tigis
%V 8
%N 
%P 26-35
%@ 1211-7579
%X 



%0 Journal Article
%A Balcar, Vladimir
%A Stastny, Frantisek
%A Tejkalova, Hana
%A Skuba, Irina
%A Palenicek, Tomas
%A Pliss, Lioudmila
%A Mares, Vladislav
%A Kristofikova, Zdena
%A Kaiser, Miroslav
%A Bubenikova, Vera
%A Balcar, Vladimir
%T Interactions of Dopamine D1/D2 Receptor with Glutamate Receptor of NMDA type: from Molecules to Animal Models of Schizophrenia (in Czech)
%B Psychiatrie (Prague)
%D 2004
%C Prague
%I Tigis
%V 8
%N 
%P 26-35
%@ 1211-7579
%X 



%0 Journal Article
%~ Pubmed
%A Rae, Caroline
%A McQuillan, James A
%A Parekh, Sapan B
%A Bubb, William A
%A Weiser, Silvia
%A Balcar, Vladimir J
%A Hansen, Anna M
%A Ball, Helen J
%A Hunt, Nicholas H
%T Brain gene expression, metabolism, and bioenergetics: interrelationships in murine models of cerebral and noncerebral malaria.
%B The FASEB journal : official publication of the Federation of American Societies for Experimental Biology
%D 2004
%V 18
%N 3
%P 499-510
%@ 1530-6860
%X Malaria infection can cause cerebral symptoms without parasite invasion of brain tissue. We examined the relationships between brain biochemistry, bioenergetics, and gene expression in murine models of cerebral (Plasmodium berghei ANKA) and noncerebral (P. berghei K173) malaria using multinuclear NMR spectroscopy, neuropharmacological approaches, and real-time RT-PCR. In cerebral malaria caused by P. berghei ANKA infection, we found biochemical changes consistent with increased glutamatergic activity and decreased flux through the Krebs cycle, followed by increased production of the hypoxia markers lactate and alanine. This was accompanied by compromised brain bioenergetics. There were few significant changes in expression of mRNA for metabolic enzymes or transporters or in the rate of transport of glutamate or glucose. However, in keeping with a role for endogenous cytokines in malaria cerebral pathology, there was significant up-regulation of mRNAs for TNF-alpha, interferon-gamma, and lymphotoxin. These changes are consistent with a state of cytopathic hypoxia. By contrast, in P. berghei K173 infection the brain showed increased metabolic rate, with no deleterious effect on bioenergetics. This was accompanied by mild up-regulation of expression of metabolic enzymes. These changes are consistent with benign hypermetabolism whose cause remains a subject of speculation.



%0 Journal Article
%~ Pubmed
%A Jeffrey, Peter L
%A Balcar, Vladimir J
%A Tolhurst, Ornella
%A Weinberger, Ron P
%A Meany, Jenny A
%T Avian Purkinje neuronal cultures: extrinsic control of morphology by cell type and glutamate.
%B Methods in cell biology
%D 2003
%V 71
%N 
%P 89-109
%@ 0091-679X
%X An in vitro coculture system is described to study the avian Purkinje neuron and the interactions occurring with astrocytes and granule cells during development in the cerebellum. Astrocytes initially and granule cells later regulate Purkinje neuron morphology. The coculture system presented here provides an excellent system for investigating the morphological, immunocytochemical, and electrophysiological differentiation of Purkinje neurons under controlled conditions and for studying cell-cell interactions and extrinsic factors, e.g., glutamate in normal and neuropathological conditions.
%Z FOR Codes: 110199



%0 Journal Article
%A Stanton, D
%A Liao, LP
%A Moussa, CE-H
%A Bubb, WA
%A Rae, CD
%A Balcar, VJ
%T Can inhibition of glutamate transport contribute to the actions of neuroleptics?
%B Psychiatrie
%D 2003
%C France
%I Medica-Press International
%V 7
%N 
%P 6-11
%@ 1211-7579
%X 



%0 Conference Proceedings
%A Bubenikova, V
%A Balcar, VJ
%A Tejkalova, H
%A Horacek, J
%A St'astny, F
%T Significance of neonatal excitotoxic brain lesions in a neurodevelopmental model of schizophrenia
%B Psychiatrie
%D 2003
%C 
%I Medica-Press International, France
%V 7(S2)
%N 
%P 19-20
%@ 1211-7579
%X 



%0 Journal Article
%A Rae, CD
%A McQuillan, JA
%A Parekh, S
%A Bubb, WA
%A Weiser, S
%A Balcar, VJ
%A Hansen, AM
%A Ball, HJ
%A Hunt, NH
%T Brain gene expression, metabolism, and bioenergetics: interrelationships in murine models of cerebral and noncerebral malaria
%B Faseb Journal
%D 2003
%C 9650 ROCKVILLE PIKE, BETHESDA, USA, MD, 20814-399
%I Federation Amer Soc Exp Biol
%V 18
%N 
%P 499-510
%@ 0892-6638
%X 



%0 Journal Article
%A Wallis, T
%A Bubb, WA
%A McQuillan, JA
%A Balcar, VJ
%A Rae, CD
%T For want of a nail. Ramifications of a single gene deletion, dystrophin, in the brain of the mouse
%B Frontiers In Bioscience
%D 2003
%C C/O NORTH SHORE UNIV HOSPITAL, BIOMEDICAL RESEARCH CENTER, 350 COMMUNITY DR, MANHASSET, USA, NY, 1103
%I Frontiers In Bioscience Inc
%V 9
%N 
%P 74-84
%@ 1093-9946
%X 



%0 Journal Article
%A Stasny, F
%A Lisy, V
%A Mares, V
%A Jezova, D
%A Santamaria, A
%A Balcar, VJ
%T Functional glutamate resceptors are expressed in rat brain capillary barrier
%B Psychiatrie
%D 2003
%C France
%I Medica-Press International
%V 7 (2)
%N 
%P 127-128
%@ 1211-7579
%X 



%0 Journal Article
%A St Asny, F
%A Tejkalova, H
%A Hoschel, C
%A Balcar, VJ
%T Viral infection, glutamatergic deficit and behavioural changes in animal model of schizophrenia
%B Psychiatrie
%D 2003
%C France
%I Medica-Press International
%V 7
%N 
%P 128-130
%@ 1211-7579
%X 



%0 Journal Article
%A Pliss, L
%A Balcar, VJ
%A Bubenikova, V
%A Pokorny, J
%A Fitzgibbon, T
%A St'astny, F
%T Morphology and ultrastructure of rat hippocampal formation after I.C.V administration of N-ACETYL-l-ASPARTYL-l-GLUTAMATE
%B Neuroscience
%D 2003
%C THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD, ENGLAND, OX5 1G
%I Pergamon-Elsevier Science Ltd
%V 122(2003)
%N 
%P 93-101
%@ 0306-4522
%X 



%0 Journal Article
%~ Pubmed
%A Rae, Caroline
%A Hare, Nathan
%A Bubb, William A
%A McEwan, Sally R
%A Br?er, Angelika
%A McQuillan, James A
%A Balcar, Vladimir J
%A Conigrave, Arthur D
%A Br?er, Stefan
%T Inhibition of glutamine transport depletes glutamate and GABA neurotransmitter pools: further evidence for metabolic compartmentation.
%B Journal of Neurochemistry
%D 2003
%V 85
%N 2
%P 503-14
%@ 0022-3042
%X The role of glutamine and alanine transport in the recycling of neurotransmitter glutamate was investigated in Guinea pig brain cortical tissue slices and prisms, and in cultured neuroblastoma and astrocyte cell lines. The ability of exogenous (2 mm) glutamine to displace 13C label supplied as [3-13C]pyruvate, [2-13C]acetate, l-[3-13C]lactate, or d-[1-13C]glucose was investigated using NMR spectroscopy. Glutamine transport was inhibited in slices under quiescent or depolarising conditions using histidine, which shares most transport routes with glutamine, or 2-(methylamino)isobutyric acid (MeAIB), a specific inhibitor of the neuronal system A. Glutamine mainly entered a large, slow turnover pool, probably located in neurons, which did not interact with the glutamate/glutamine neurotransmitter cycle. This uptake was inhibited by MeAIB. When [1-13C]glucose was used as substrate, glutamate/glutamine cycle turnover was inhibited by histidine but not MeAIB, suggesting that neuronal system A may not play a prominent role in neurotransmitter cycling. When transport was blocked by histidine under depolarising conditions, neurotransmitter pools were depleted, showing that glutamine transport is essential for maintenance of glutamate, GABA and alanine pools. Alanine labelling and release were decreased by histidine, showing that alanine was released from neurons and returned to astrocytes. The resultant implications for metabolic compartmentation and regulation of metabolism by transport processes are discussed.
%Z FOR Codes: 110199



%0 Journal Article
%~ Pubmed
%A Moussa, Charbel El-Hajj
%A Mitrovic, Ann D
%A Vandenberg, Robert J
%A Provis, Tanya
%A Rae, Caroline
%A Bubb, William A
%A Balcar, Vladimir J
%T Effects of L-glutamate transport inhibition by a conformationally restricted glutamate analogue (2S,1'S,2'R)-2-(carboxycyclopropyl)glycine (L-CCG III) on metabolism in brain tissue in vitro analysed by NMR spectroscopy.
%B Neurochemical research
%D 2002
%V 27
%N 1-2
%P 27-35
%@ 0364-3190
%X (2S,1'S,2'R)-2-(Carboxycyclopropyl)glycine (L-CCG III) was a substrate of Na(+)-dependent glutamate transporters (GluT) in Xenopus laevis oocytes (IC50 to approximately 13 and to approximately 2 microM for, respec tively, EAAT 1 and EAAT 2) and caused an apparent inhibition of [3H]L-glutamate uptake in "mini-slices" of guinea pig cerebral cortex (IC50 to approximately 12 microM). In slices (350 microM) of guinea pig cerebral cortex, 5 microM L-CCG III increased both the flux of label through pyruvate carboxylase and the fractional enrichment of glutamate, GABA, glutamine and lactate, but had no effect on total metabolite pool sizes. At 50 microM L-CCG III decreased incorporation of 13C from [3-13C]-pyruvate into glutamate C4, glutamine C4, lactate C3 and alanine C3. The total metabolite pool sizes were also decreased with no change in the fractional enrichment. Furthermore, L-CCG III was accumulated in the tissue, probably via GluT. At lower concentration, L-CCG III would compete with L-glutamate for GluT and the changes probably reflect a compensation for the "missing" L-glutamate. At 50 microM, intracellular L-CCG III could reach > 10 mM and metabolism might be affected directly.
%Z FOR Codes: 110199



%0 Journal Article
%A Takamoto, A
%A Quiggin, LB
%A Lieb, I
%A Shave, E
%A Balcar, VJ
%A Yoneda, Y
%T Differences between D- and L-aspartate binding to the Na+-dependent binding sites on glutamate transporters in frozen sections of rat brain
%B Life Sciences
%D 2002
%C The Boulevard, Langford Lane,Kidlington, Oxford, England, Ox5 1Gb
%I Pergamon-Elsevier Science Ltd
%V 70
%N 
%P 991-1001
%@ 0024-3205
%X 



%0 Journal Article
%A Hinoi, E
%A Balcar, VJ
%A Kuramoto, N
%A Nakamichi, N
%A Yoneda, Y
%T Nuclear transcription factors in the hippocampus
%B Progress In Neurobiology
%D 2002
%C The Boulevard, Langford Lane,Kidlington, Oxford, England, Ox5 1Gb
%I Pergamon-Elsevier Science Ltd
%V 68
%N 
%P 145-165
%@ 0301-0082
%X 



%0 Journal Article
%A Hinoi, E
%A Fujimori, S
%A Balcar, VJ
%A Kubo, K
%A Ogita, K
%A Yoneda, Y
%T Constitutive expression of heterologous N-Methyl-D-aspartate receptor subunits in rat adrenal medulla
%B Journal Of Neuroscience Research
%D 2002
%C Div John Wiley & Sons Inc,605 Third Ave, New York, Ny, 10158-0012
%I Wiley-Liss
%V 68
%N 
%P 36-45
%@ 0360-4012
%X 



%0 Journal Article
%A Balcar, VJ
%T Molecular pharmacology of the Na+-dependent transport of acidic amino acids in the mammalian central nervous system
%B Biological & Pharmaceutical Bulletin
%D 2002
%C 2-12-15-201 Shibuya,Shibuya-Ku, Tokyo, Japan, 150
%I Pharmaceutical Soc Japan
%V 25 (3)
%N 
%P 291-301
%@ 0918-6158
%X 



%0 Journal Article
%A Hirai, T
%A Kuramoto, N
%A Maruyama, H
%A Balcar, VJ
%A Nakamura, Y
%A Yoneda, Y
%T Petentiation of Nuclear Activator Protein-1 DNA binding following brief exposure to N-Methly-D-Aspartate in immature cultured rat hippocampal neurons
%B Journal Of Neuroscience Research
%D 2002
%C Div John Wiley & Sons Inc,605 Third Ave, New York, Ny, 10158-0012
%I Wiley-Liss
%V 67
%N 
%P 523-532
%@ 0360-4012
%X 



%0 Journal Article
%A Pliss, L
%A Jezova, D
%A Mares, V
%A Balcar, VJ
%A Stastny, F
%T N-Acetyl-L-aspartyl-L-glutamate changes functional & structural properties of rat blood-brain barrier
%B Neuroscience Letters
%D 2002
%C Customer Relations Manager,Bay 15, Shannon Industrialestate Coclare, Ireland
%I Elsevier Sci Ireland Ltd
%V 317
%N 
%P 85-88
%@ 0304-3940
%X 



%0 Journal Article
%A Balcar, VJ
%A Takamoto, A
%A Yonida, Y
%T Neurochemistry of L-glutamiate transport in the CNS: A review of the thirty years of progress
%B Collection of Czechoslovak Chemical Communications
%D 2001
%C 84 Theobalds Rd, London, England, Wc1X 8Rr
%I Lancet Ltd
%V 358
%N 
%P 1941-1945
%@ 0140-6736
%X 



%0 Journal Article
%A Shave, E
%A Pliss, L
%A Lawrence, M
%A Fitzgibbon, T
%A Stastny, F
%A Balcar, VJ
%T Regional distribution and pharmacological characteristics of [3H]N-acetyle-aspartyl-glutamate (NAAG) binding sites in rat brain
%B Neurochemistry International
%D 2001
%C Po Box 319, Curtin, Australia, 2600
%I Public Health Assoc Australia Inc
%V 25 (3)
%N 
%P 203-211
%@ 1326-0200
%X 



%0 Journal Article
%A Shave, E
%A Pliss, L
%A Lawrence, M
%A FitzGibbon, T
%A Stastny, F
%A Balcar, VJ
%T Regional distribution & pharmacological characteristics of [3H]n-acetyl-aspartyl-glutamate (NAAG) binding sites in rat brain
%B Neurochemistry International
%D 2000
%C 
%I Pergamon-Elsevier Science Ltd
%V 38 (1)
%N 
%P 53-62
%@ 0197-0186
%X 



%0 Journal Article
%A Rae, CD
%A Lawrence, M
%A Dias, LS
%A Provis, T
%A Bubb, WA
%A Balcar, VJ
%T Strategies for studies of neurotoxic mechanisms involving deficient transport of L-glutamate: antisense knockout in rat brain in vivo and changes in the neurotransmitter metabolism following inhibition of glutamate transport in guinea pig brain slices
%B Brain Research Bulletin
%D 2000
%C 
%I Elsevier Science
%V 53
%N 
%P 373-381
%@ 0361-9230
%X 



%0 Journal Article
%A Berry, DA
%A Balcar, VJ
%A Barden, JA
%A Keogh, A
%A dos Remedios, CG
%T Determination of P2X1 (alpha)-sarcoglycan (adhalin) expression levels in failing human dilated cardiomyopathic left ventricles
%B Electrophoresis
%D 2000
%C 
%I Wiley-Vch
%V 21 (170
%N 
%P 3857-3862
%@ 0173-0835
%X 



%0 Journal Article
%A Pliss, L
%A FitzGibbon, T
%A Balcar, VJ
%A St'astny, F
%T Neurotoxicity of NAAG in vivo is sensitive to NMDA antagonists and mGluR II ligands
%B NeuroReport
%D 2000
%C 
%I Lippincott Williams & Wilkins
%V 11 (16)
%N 
%P 3651-3654
%@ 0959-4965
%X 



%0 Journal Article
%A Lieb, I
%A Collins, M
%A Cooper, B
%A Dias, LS
%A Balcar, VJ
%T Quantitative autoradiography of Na+ -dependent [3H]L-aspartate binding to L-glutamate transporters in rat brain: structure-activity studies using L-trans-pyrrolidine-2, 4-dicarboxylate (L-t-PDC) and 2-(carboxycyclopropyl)-glycine (CCG)
%B Neurochemistry International
%D 2000
%C 
%I Pergamon-Elsevier Science Ltd
%V 36 (4-5)
%N 
%P 319-327
%@ 0197-0186
%X 



%0 Journal Article
%A Duke, RK
%A Collins, M
%A Balcar, VJ
%A Allan, RD
%A Mewett, KN
%A Johnston, GAR
%T (+) and (-)-cis-2-Aminomethylcyclopropanecarboxylic Acids show opposite Pharmacology at recombinant p1 and p2 GABAc receptors
%B Journal of Neurochemistry
%D 2000
%C 
%I Lippincott Williams & Wilkins, Inc
%V 75 (6)
%N 
%P 2602-2610
%@ 0022-3042
%X