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l-glutamate (Glu) is the main excitatory neurotransmitter in the central nervous system (CNS) and is associated with motor behavior and sensory perception. While microdialysis methods have been used to record tonic levels of Glu, little is known about the more rapid changes in Glu signals that may be observed in awake rats. We have reported acute recording methods using enzyme-based microelectrode arrays (MEA) with fast response time and low detection levels of Glu in anesthetized animals with minimal interference. The current paper concerns modification of the MEA design to allow for reliable measures in the brain of conscious rats. In this study, we characterized the effects of chronic implantation of the MEA into the brains of rats. We were capable of measuring Glu levels for 7 days without loss of sensitivity. We performed studies of tail-pinch induced stress, which caused a robust biphasic increase in Glu. Histological data show chronic implantation of the MEAs caused minimal injury to the CNS. Taken together, our data show that chronic recordings of tonic and phasic Glu can be carried out in awake rats for up to 17 days in vivo allowing longer term studies of Glu regulation in behaving rats.

The article presents an abstract of the research paper "Diet, lipids and brain development." Formation of a myelin sheath is one of the fundamental and necessary events in the normal development of the central nervous system in vertebrates. Myelinogenesis is basically a postnatal process in rodents.

The article presents an abstract of the medical research paper "Gene Transfer in CNS," which will be discussed in the Seventeenth Biennial Meeting of the International Society for Neurochemistry and the Thirteenth General Meeting of the European Society for Neurochemistry, to be held during August 8-14, 1999 in Berlin, Germany. The paper demonstrates the improved efficacy of gene transfer via cationic cholesterol-containing liposomes in the central nervous system of a rat.

The article presents an abstract of the paper "Nicotine Induced Changes in Gene Expression in the Central Nervous System," which will be presented at the 30th annual meeting of the American Society for Neurochemistry to be held from March 14-17, 1999 in New Orleans, Louisiana. The paper discusses the changes in gene expression associated with addiction to nicotine in the central nervous system.

The mechanisms underlying developmental myelination have therapeutic potential following CNS injury and degeneration. We report that transplanted central glial (CG)-4 cells had a diminished myelinating capacity in myelin-deficient ( md) rats when cells express a mutated form of Tau (Tau [688]), which binds Fyn but not the microtubules. In the brain of the md rats, Tau [688]-transfected CG-4 cells displayed a decrease in cellular process outgrowth and myelination; in the spinal cord the extent of myelination rostral and caudal to the injection site was decreased. In contrast, control Tau [605]-transfected CG-4 cells formed long cellular processes and substantial areas of myelin both in the brain and spinal cord. In culture, Tau [688]-transfected CG-4 cells displayed a decrease in cellular process outgrowth, and Fyn localized largely in the cell body, not the processes. Thus, Tau in oligodendrocytes plays a key role in myelination, and a functional Tau-Fyn interaction might have therapeutic potential during demyelination and myelin repair following CNS injury and degeneration. [ABSTRACT FROM AUTHOR]

Repulsive guidance molecule A (RGM A) was recently described as a potent inhibitor of neuroregeneration in a rat spinal cord injury model. The receptor mediating RGM A’s repulsive activity was shown to be Neogenin, a member of the Deleted in Colorectal Cancer (DCC) family of netrin receptors. Binding of RGM A to Neogenin induces activation of the small GTPase RhoA and of its effector Rho-kinase by an unknown mechanism. Here we show, that the cytoplasmic tail of Neogenin interacts directly with the transcriptional coactivator LIM domain only 4 (LMO4) in human SH-SY5Y cells, human Ntera neurons, and in embryonic rat cortical neurons. RGM A binding to Neogenin but not binding of Netrin-1, induces release of LMO4 from Neogenin. Down-regulation of LMO4 neutralizes the repulsive activity of RGM A in neuronal cell lines and embryonic rat cortical neurons and prevents RhoA activation. These results show for the first time that an interaction of Neogenin with LMO4 is involved in the RGM A – Neogenin signal transduction pathway for RhoA activation. [ABSTRACT FROM AUTHOR]

The peptide transmitter N-acetylaspartylglutamate (NAAG) is present in millimolar concentrations in mammalian spinal cord. Data from the rat peripheral nervous system suggest that this peptide is synthesized enzymatically, a process that would be unique for mammalian neuropeptides. To test this hypothesis in the mammalian CNS, rat spinal cords were acutely isolated and used to study the incorporation of radiolabeled amino acids into NAAG. Consistent with the action of a NAAG synthetase, inhibition of protein synthesis did not affect radiolabel incorporation into NAAG. Depolarization of spinal cords stimulated incorporation of radiolabel. Biosynthesis of NAAG by cortical astrocytes in cell culture was demonstrated by tracing incorporation of [3H]-glutamate by astrocytes. In the first test of the hypothesis that NAA is an immediate precursor in NAAG biosynthesis, [3H]-NAA was incorporated into NAAG by isolated spinal cords and by cell cultures of cortical astrocytes. Data from cerebellar neurons and glia in primary culture confirmed the predominance of neuronal synthesis and glial uptake of NAA, leading to the hypothesis that while neurons synthesize NAA for NAAG biosynthesis, glia may take it up from the extracellular space. However, cortical astrocytes in serum-free low-density cell culture incorporated [3H]-aspartate into NAAG, a result indicating that under some conditions these cells may also synthesize NAA. Pre-incubation of isolated spinal cords and cultures of rat cortical astrocytes with unlabeled NAA increased [3H]-glutamate incorporation into NAAG. In contrast, [3H]-glutamine incorporation in spinal cord was not stimulated by unlabeled NAA. These results are consistent with the glutamate–glutamine cycle greatly favoring uptake of glutamine into neurons and glutamate by glia and suggest that NAA availability may be rate-limiting in the synthesis of NAAG by glia under some conditions. [ABSTRACT FROM AUTHOR]

The article presents an abstract of the research paper "Qualitative and Quantitative Changes in a ß-Trace Protein in Cerebrospinal Fluid of Patients with Degenerative and Other Neurological Disorders." ß-Trace Protein is the most abundant component among human cerebrospinal fluid proteins. It is a glycoprotein which has got a potent affinity to lipophilic small molecules and works as their transporter in the central nervous system.

The article presents an abstract of the research paper "Mitochondrial Respiratory Chain Complex Deficiency in Human Epileptic Hippocampus." The research determines that selective changes in the activity of complex 1 of mitochondrial oxidative phosphorylation occur in epileptogenic human central nervous system tissue. The research shows that the local functional impairment of mitochondria in human hippocampus can be a novel pathomechanism in temporal lobe epilepsy.

The article presents an abstract of the research paper "Mechanisms of Gene Regulation by NF-B and Stress in the Central Nervous System." Cumulative oxidative damage may lead to increased apoptosis. This may be due to chronic exposure to the reactive oxygen species byproducts of oxidative metabolism and neurotransmitter signaling pathways.

The article presents an abstract of the research paper "Pathways Underlying the Disposal of H2O2 in the Mitochondria of the Central Nervous System." The findings indicate that isocitrate dehydrogenase, malic enzyme and nicotinamide nucleotide transhydrogenase contribute to the regeneration of mitochondrial NAPDH required for the reduction of oxidized glutathione, which in turn is produced during elimination of H2O2 by the glutathione system.

The article presents an abstract of the research paper "L-Glutamic Acid - Endogenic Differentiation Factor of HL-60 Cells." The research shows that L-Glutamic acid (L-Glu) is known to be the important neuromediator in the central nervous system and is acting through different types of glutamate receptors. The research finds that L-Glu decreased the expression level of mRNA of IL-1 and IL-6, and increased the expression of mRNA of TNF-a.

The article presents an abstract of the research paper "Expression of the Glycoprotein AN2 on Early Progenitor Cells of the Central Nervous System." Researchers in the study determine the developmental properties of AN2+ cells in vitro and after transplantation. They characterize the developmental pattern of AN2 expression on brain sections.

The article presents an abstract of the research paper "A Role for Pax6 in Rhombic Lip Derived Neurons." The study shows that Pax6 is a key regulator in central nervous system, and eye development. The study determines that Pax6 plays a strong role during hindbrain migration processes. According to the study, neurons of the precerebellar nuclei are generated at the lower rhombic lip.

The article presents an abstract of the research paper "Expression of CD137, a Member of the Tumour Necrosis factor Receptor Superfamily, in the Developing Human Brain." The study findings suggest that CD137 can play a role in cell-cell interaction during the human brain development and in central nervous system diseases.

The article presents an abstract of the research paper "Characterization of Verotoxin Receptors and its Distribution in Central Nervous System." The research study examined the binding of verotoxin to several receptor glycolipids. The immunohistochemical studies on antibodies demonstrated the existence of verotoxin receptor in small sensory neurons in dorsal root ganglia of human, rabbit, rat and mouse.

The article presents an abstract of the research paper "Effect of Acute Prenatal Hypoxic Hypoxia on the GABAA Receptor Complex in Developing CNS." The work found that hypoxic conditions modify CNS neurotransmission. It will be presented in the joint meeting of the International Society for Neurochemistry and the European Society of Neurochemistry that will be held in Berlin, Germany from August 8-14, 1999.

The article presents an abstract of the research paper "Effects of Endogenous Neurosteroid Chronic Administration on the GABAA-receptor in avian CNS." The data indicate that chronic epipregnanolone treatment in ovo produces homologous uncoupling between the neurosteroid modulatory site and the GABA-benzodiazepine receptor sites.

The article presents an abstract of the research paper "Effects of Ammonia on Glutamate (glt-1 and glast) Transporter Expression in Cultured Astrocytes." It concludes that pathogenesis of central nervous system dysfunction in hyperammonemic disorders such as urea cycle enzymopathies and HE may act as factor in increasing extracellular concentrations of glutamate.

The article presents an abstract of the research paper "Vinpocetine Inhibits Glutamate and Aspartate Release Evoked by the Elevation of Internal Sodium." The study was aimed at understanding the mechanism understanding underlying mechanism for neuroprotective action of vinpocetine in the Central Nervous System.

The article presents an abstract of the research paper "Microglia-Dependent Neurodegeneration: An In Vitro Model." It will be presented in the joint meeting of the International Society for Neurochemistry and the European Society of Neurochemistry that will be held in Berlin, Germany from August 8-14, 1999. Microglial cells adopt an activated phenotype when a pathological situation arises in the central nervous system.

The article presents an abstract of the research paper "Potassium Potentiates Nitric Oxide Production by Cultured Microglia." It will be presented in the joint meeting of the International Society for Neurochemistry and the European Society of Neurochemistry that will be held in Berlin, Germany from August 8-14, 1999. In some diseases of central nervous system, a key role is played by the activation of microglia.

The article presents an abstract of the research paper "The Accumulation And Differentiation Of Oligodendrocyte Progenitors Following Mature Oligodendrocyte Apoptosis." The model of cuprizone intoxication to induce synchronous demyelination of the corpus callosum is utilized to examine mature oligodendrocytes during demyelination. Oligodendrocyte progenitors cells are responsible for remyelinating demyelinated lesions within the central nervous system.

The article presents an abstract of the research paper "Function Of Na+-K+-2CL- Cotransporter in Astrocytes." The role played by Na+-K+-2CL- Cotransporter in astrocytes is important as it helps in the regulation of ion homeostasis in the central nervous system. It is found that differentiated astrocytes changed from a polygonal to process-bearing morphology, showing alike a characteristic of matured and reactive astrocytes in situ.

The article presents an abstract of the research paper "Mechanism of α- Ketoisocaproate Accumulation in Rat Cerebral Cortical Neurons." It will be presented in the joint meeting of the International Society for Neurochemistry and the European Society of Neurochemistry that will be held in Berlin, Germany from August 8-14, 1999. The main excitatory neurotransmitter of the central nervous system, glutamate, is produced in neurons with the help of glutamine sysnthesized in glial cells.

The article presents an abstract of the study "Lipid Signal Molecules and their Regulation During Oxidative Stress in the Developing Brain." The research paper for the study would be presented in the 30th Annual Meeting of the American Society for Neurochemistry, on March 14-17, 1999, in New Orleans, Louisiana.