bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of glycine and glyoxylate on cerebral glucose oxidation in vitro
Authors: Dennis M. J. , Clarke J. T. R. 
Published: October 2006

In Patients with nonketotic hyperglycinemia (NKHG), the principal route of glycine catabolism in the CNS is interrupted by an hereditary defect in the glycine cleavage reaction [5, 10‐methylenetetrahydrofolate: ammonia hy‐droxymethyltransferase (decarboxylating, oxidizing); EC 2.1.2.10] (ANDO el al, 1968; Perryet al, 1975). The resulting accumulation of glycine in cerebral tissue of affected infants is invariably associated with the development of severe brain damage, though the mechanism of the damage is still unknown.The rapidity of onset of the condition, which often occurs within a few hours after birth, along with the severity and irreversibility of the cerebral damage, suggests that some critical metabolic process is affected by the accumulation of glycine or one of its normally minor metabolites. The study reported here was undertaken to determine the effects of glycine and its α‐ketoacid metabolite, glyoxylate, on glucose oxidation in immature rat brain slices, and whether glyoxylate accumulation in NKHG might account for the severe brain damage occurring with the disease. The results showed that although glyoxylate markedly inhibited cerebral glucose oxidation in vitro, excess amounts of the compound could not be demonstrated in NKHG brain.
Subcellular Distribution of Glutamate Decarboxylase in Rat Olfactory Bulb: High Content in Dendrodendritic Synaptosomes
Authors: Quinn Michael R. , Cagan Robert H. 
Published: October 2006

Abstract: The olfactory bulbs in the CNS contain reciprocal dendrodendritic synapses between the granule cells and the secondary dendrites of mitral cells. Based on pharmacologic and electrophysiologic evidence, these synapses are believed to utilize GABA as an inhibitory neurotransmitter. A dendrodendritic synaptosomal fraction has been isolated from rat olfactory bulbs. The upper portion (PB) of the crude nuclear pellet contains 30–40% of the GAD (glutamate decarboxylase) activity of the olfactory bulb homogenate. When PB is purified on a discontinuous sucrose density gradient, 78–85% of the GAD activity is localized to the region containing the dendrodendritic synaptosomes, which were identified by transmission electron microscopy. The presence of a substantial proportion of GAD, the enzyme that catalyzes synthesis of GABA, in the DDS provides neurochemical support for the hypothesis that GABA functions at the reciprocal dendrodendritic synapses in the olfactory bulb.
α‐Guanidinoglutaric Acid in Cobalt‐Induced Epileptogenic Cerebral Cortex of Cats
Authors: Mori Akitane , Akagi Masayuki , Katayama Yasuto , Watanabe Yoko 
Published: October 2006

Abstract: Guanidino compounds in the cobalt‐induced epileptogenic cerebral cortex of cats were fluorometrically analysed by a JASCO G‐520 guanidino compounds analyser, and an unknown high peak was observed in the chromatogram that was identical to the peak of authentic α‐guanidinoglutaric acid. In another experiment, the substance was extracted from the cobalt focus tissue, converted into dimethylpyrimidyl derivative‐butylester, and analysed by a GC/MS technique. The mass spectrum of the substance was identical to the dimethylpyrimidyl derivative of α‐guanidinoglutaric acid butylester (M+= 365).
Choline High‐Affinity Uptake and Metabolism and Choline Acetyltransferase Activity in the Striatum of Rats Chronically Treated with Neuroleptics
Authors: Pedata F. , Sorbi S. , Pepeu G. 
Published: October 2006

Abstract: High‐affinity uptake of choline and choline acetyltransferase activity (ChAT) were measured in the striatum of rats treated for 45–60 days with haloperidol (1 mg/kg per os) and pimozide (1 mg/kg per os) daily and with fluspirilene (1 mg/kg i.m.) twice a week. Haloperidol and fluspirilene caused a 29%, and pimozide a 38%, increase in high‐affinity uptake of choline. They also caused a significant decrease in ChAT activity: haloperidol, 20%; pimozide, 27%; and fluspirilene, 42%. In rats treated with fluspirilene for 65–80 days the metabolism of [3H]choline taken up by striatal synaptosomes was investigated. A 33% increase in total radioactivity, a significant increase in labelled acetylcholine (ACh), a relative decrease in labelled choline, and no change in labelled phosphorylcholine and betaine were found. It is concluded that the increase in high‐affinity choline uptake caused by chronic administration of neuroleptic drugs is associated with a parallel increase in choline utilization for ACh formation. On the other hand, the decrease in ChAT activity does not appear to influence ACh formation.
l‐Pipecolate Formation in the Mammalian Brain. Regional Distribution of Δ1Pyrroline‐2‐carboxylate Reductase Activity
Authors: Garweg G. , Rehren D. Von , Hintze U. 
Published: October 2006

Abstract: lPipecolate formation exhibits considerable regional differences in the central nervous system of the mouse, dog, and monkey, as reflected in measurements of the activity of Δ1‐pyrroline‐2‐carboxylate reductase (E.C. 1.5.1.1). The rate of reduction of Δ1‐piperidine‐2‐carboxylate was high in certain telencephalic and diencephalic regions, lower in the brain stem, and not measurable in the cerebellum and spinal cord. In addition to Δ1‐piperidine‐2‐carboxylate, Δ1‐pyrroline‐2‐carboxylate was also found to be a substrate for the same enzyme in homogenates of mouse forebrain. Enzyme kinetic data for both substrates and, in addition, for NADH were derived from determinations using enzyme fractions of mouse telencephalon. The discussion is based on earlier findings concerning the utilisation of d‐proline in the neuronal protein synthesis of mouse brain.
Turnaround of Axoplasmic Transport of Selected Particle‐Specific Enzymes at an Injury in Control and Diisopropylphosphorofluoridate‐Treated Rats
Authors: Schmidt Robert E. , C. Yu Margaret J. , McDougal, David B. 
Published: October 2006

Abstract: Reversal of direction (turnaround) of axonal transport of particle specific enzyme activities was studied at a ligature placed on rat sciatic nerve. In the principal experiment, the ligature remained on the nerve in vivo several hours, allowing enzyme activities (acetylcholinesterase, acid phosphatase, and monoamine oxidase) to accumulate immediately proximal to the tie. The nerve was then tied a second time, proximal to the first tie, and incubated in vitro for several more hours. Accumulation of enzyme activities just distal to the second tie was measured. This second accumulation, of activities traveling in the retrograde direction, was shown to be the result of turnaround in several ways. (1) The increase in activity distal to the second tie was equal to the decrease in activity proximal to the first. (2) The increase in enzyme activities distal to the second tie was greatly reduced when the accumulation proximal to the first tie was trapped by placing a third tie between the first and second ties. (3) It was shown that the activity that accumulated distal to the second tie could not have been in retrograde motion at the time of the first tie. (4) Accumulation distal to the second tie was not a function of the length of nerve segment included between the two ties. In contrast to the consistent occurrence of turnaround of orthograde flow, turnaround of retrograde flow could not be demonstrated. Turnaround transport was blocked by incubation in the cold and in the presence of NaCN or vinblastine. The turnaround process operated on all three enzymes studied, suggesting that it operates on lysosomes and mitochondria, as well as on the endoplasmic reticulum‐like material bearing acetylcholinesterase. Evidence for the participation of the transport process in the renewal of AChE in the distal portions of the axon was obtained in experiments using diisopropylphosphorofluoridate and cycloheximide.
Effects of N‐Ethylmaleimide Treatment on the Action Potential Na+‐Ionophore of Cultured Neuroblastoma Cells
Authors: Panini Aruna , Blumenthal Kenneth 
Published: October 2006

Abstract: Treatment of murine neuroblastoma N18 cells with N‐ethylmaleimide under conditions that favor diminution of membrane potential leads to a 65% increase in the rate of veratridine‐stimulated, tetrodotoxin‐sensitive Na+ uptake and to a 50% decrease in the concentration of veratridine required for half‐maximal stimulation. This modification does not appear to occur in N18 cells having a normal membrane potential of approx. ‐40 mV. The data are consistent with the involvement of a sulfhydryl group in the Na+ channel inactivation gate and in the conformational change in this gate which results in closing of the channel.
Lack of Effect of Repeated Electroconvulsive Shock on [3H]Spiroperidol and [3H]5‐Hydroxytryptamine Binding and Cholinergic Parameters in Rat Brain
Authors: Atterwill C. K. 
Published: October 2006

Abstract: Repeated electroconvulsive shock (ECS) administered on alternate days for 10 days produced no changes in rat striatal [3H]spiroperidol binding measured 24 h after the last shock compared to anaesthetised controls. Similarly, there was no change in whole brain specific [3H]5‐HT binding. Sodiumdependent high affinity [3H]choline uptake (HAUC) and ChAT were also unaltered in striatal and hippocampal samples following repeated ECS. Acute administration of Pentylenetetrazol did produce an increase in hippocampal HAUC immediately postictally. However, ECS (XI) did not change HAUC measured 1 h postictally. An effect of halothane on HAUC was noted in these experiments indicating the importance of an evaluation of anaesthetic effects in ECS studies.
No Evidence for Lateral Asymmetry of Neurotransmitters in Post‐Mortem Human Brain
Authors: Rossor M. , Garrett N. , Iversen L. 
Published: October 2006

Abstract: A study of post‐mortem human brain was undertaken to establish whether there is any evidence for lateral asymmetry of neurotransmitters. Choline acetyltransferase, glutamic acid decarboxylase, α‐aminobutyric acid, dopamine and noradrenaline were measured in nine comparable areas from the left and right hemispheres of normal post‐mortem human brain. Only nigral GABA showed a left‐right difference at a significance level of 5%. These negative post‐mortem findings suggest that chemical laterality is unlikely to be an important source of error in human post‐mortem studies.
Cyclic AMP‐Generating Systems in Cell‐Free Preparations from Guinea Pig Cerebral Cortex: Loss of Adenosine and Amine Responsiveness Due to Low Levels of Endogenous Adenosine
Authors: McNeal E. T. , Creveling C. R. , Daly J. W. 
Published: October 2006

AbstractThe accumulations of radioactive cyclic AMP elicited by adenosine, norepinephrine, and histamine in adenine‐labeled vesicular entities of a particulate fraction from guinea pig cerebral cortex are greatly reduced as a result of prolonged preincubation. The presence of adenosine deaminase during preincubations largely prevents the loss of adenosine, norepinephrine and histamine responses. Adenosine deaminase was inactivated by deoxycoformycin prior to stimulation of cyclic AMP accumulation by adenosine or amines. If adenosine deaminase is not inactivated, responses to norepinephrine are not significant and histamine responses are reduced by 50%. Adenosine deaminase cannot restore responsiveness of the cyclic AMP‐generating systems. It is proposed that, in participate fractions of guinea pig cerebral cortex, low levels of adenosine cause a slow loss of receptors and/or of coupling of receptors to cyclic AMP‐generating systems.
Bovine Peripheral Nervous System Myelin P2 Protein: Chemical and Immunological Characterization of the Cyanogen Bromide Peptides
Authors: Weise M. J. , Hsieh D. , Hoffman P. M. , Powers J. M. , Brostoff S. W. 
Published: October 2006

AbstractCleavage of bovine P2 protein by cyanogen bromide (CNBr) produced peptide fractions CN1, CN2, and CN3 which were isolated by gel filtration chromatography. CN2 was found to contain two NH2‐terminals (lysine and valine) and accounted for both of the cysteine residues of P2. When reduced carboxymethylated P2 (RCM‐P2) was digested with CNBr, peptides CN1 and CN3 were obtained as were (1) a peptide with NH2‐terminal lysine (Lys) that contained no homoserine and only one cysteine residue and (2) a peptide with NH‐2‐terminal valine (Val) that was co‐eluted with CN3. These data and the chemical characterization of all the CNBr peptides obtained from P2 and RCM‐P2 suggest that isolated P2 protein has a structure composed of the CNBr peptides in the order CN3‐CN1‐CN2(Val)‐CN2(Lys) with an intrachain disulfide bond between the cysteine residues located in the two constituent peptides of CN2, CN2(Lys) and CN2(Val), To locate the neuritogenic region(s) within the P2 protein structure, CN1, CN2, and CN3 were tested for the ability to induce experimental allergic neuritis (EAN) in Lewis rats. The disease‐inducing sites of P2 protein were found only in CN1; neither CN2 nor CN3 produced disease. EAN induced by CN1 was comparable to that induced with P2 protein as determined by disease onset, clinical symptoms, and histologic lesions.
Axonal Transport of [3H]Fucose‐Labeled Glycoproteins in Two Intra‐Brain Tracts of the Rat
Authors: Padilla Stephanie S. , Morell Pierre 
Published: October 2006

Abstract[3H]Fucose was stereotaxically injected into the dorsalateral geniculate body (DLGB) of adult male rats, and 1 h to 10 days post‐injection the DLGB and projection site (striate cortex) were dissected out and solubilized in 1% sodium dodecyl sulfate. Each sample was analyzed for acid‐precipitable radioactivity, and radioactivity in different molecular weight classes was determined following discontinuous gel electrophoresis in cylindrical gels. The specificity of transport of radioactive glycoprotein to the striate cortex was determined by autoradiography of brain sections. Acid‐precipitable radioactivity in the DLGB peaked at 5 to 6 h, plateaued, and then declined over the time course studied. The electrophoretic distribution pattern was complex, five bands containing fucosylated protein being initially prominent, as a percentage of radioactivity on the gel, and then decreasing with time. Two discrete waves of glycoproteins arriving at the visual cortex (between 3 and 4 h and between 12 and 48 h) were observed. Quantitative differences in distribution of molecular weight classes were noted between glycoproteins transported in these two waves. Of particular interest were rapidly turning‐over proteins of molecular weights of 110,000 and 120,000 (half‐time of less than 1 day). A study of the hippocampal commissural pathway, following introduction of radioactivity into one hippocampal formation, was also conducted. The electrophoretic distribution patterns of proteins, and the changes in distribution with time, were similar to the situation in the DLGB. However, in the contralateral hippocampus three discrete waves of transport were resolved (2 to 3 h, 4 to 5 h, and then a continued gradual increase followed by another prominent rise between 1 and 2 days). Relative turnover times of different protein peaks in the hippocampal and DLGB‐cortical system were also different.
Activity of Pyridoxamine as a Substrate for Brain Pyridoxal Kinase
Authors: Gregory Jesse F. 
Published: October 2006

AbstractThe substrate activity of pyridoxamine (PM) for brain pyridoxal (PL) kinase was examined in view of a recent report which indicated that PM was a poor substrate for this enzyme. Bovine brain PL kinase was shown by liquid chromatography to catalyze the phosphorylation of PM (Km= 65 μm). The identity of the reaction product, pyridoxamine 5′‐phosphate, was confirmed by its ability to act as a substrate for liver pyridoxine (pyridoxamine) 5′‐phosphate oxidase. These results, which indicate that PM is a good substrate for brain PL kinase, are consistent with the proposed role of intracellular phosphorylation in the uptake of vitamin B‐6 brain tissue.
Purification and Subunit Structure of DNA‐dependent RNA Polymerase BII from Rat Brain Nuclei1
Authors: Yamamoto H. , Takahashi Y. 
Published: October 2006

Abstract:DNA‐dependent RNA polymerase BII from rat brain nuclei was purified by ammonium sulphate fractionation, successive chromatography on ion‐exchange resins, and glycerol density gradient centrifugation. The purified enzyme was resolved into two components (BIIa and BIIb) on native polyacrylamide gel electrophoresis. The subunit compositions of these enzymes were analysed on SDS‐polyacrylamide gel. BIIa enzyme consisted of nine subunits: BII1 (215,000), BII3 (150,000), BII4 (35,000), BII5 (25,000), BII6 (21,500), BII7 (17,500), BII8 (15,500), BII9 (14,500), and BII10 (11,500); in BIIb enzyme, which also contained nine subunits, BII1 was replaced by a BII2 (180,000) subunit. Addition of both 30% glycerol and dithiothreitol to the preparation medium was essential for stabilizing the enzyme.
Lipid Labeling After Intracerebral Injection of Radioactive Malonic Acid
Authors: Koeppen Arnulf H. , Mitzen Edward J. , Papandrea John D. 
Published: October 2006

Abstract:Growing albino rats between the ages of birth and 50 days received single intracranial injections of either [2‐14C]malonate or [1‐14C]malonate. After 1 h, 90% of the nonmalonate radioactivity was recovered in the free amino acids. Fatty acids and sterols accounted for the remainder. Most of the fatty acid radioactivity resided in palmitate and stearate. The label of the polar lipid fraction was concentrated in choline phosphoglyceride (CPG) (65%).Over half of the CPG‐fatty acid radioactivity was present in the 2‐acyl group. Fatty acid biosynthesis occurred predominantly by a de novo mechanism although some elongation was also present. The incorporation of the precursor into amino acids increased rapidly after birth and reached stable levels at 14 days. Fatty acid labeling also increased with brain growth but the fatty acid‐amino acid ratio declined steadily from birth to 50 days. Synthesis of malonyl‐CoA is the rate‐limiting step in the biosynthesis of amino acids, fatty acids, and sterols from free malonic acid.
An Improved DEAE‐Cellulose Filter Assay for Colchicine Binding Protein (During Mouse Brain Development)
Authors: Tse C. , Doherty R. A. 
Published: October 2006

Abstract:A DEAE‐cellulose filter assay for colchicine binding protein (CBP) has been modified to include 1 m‐sucrose in the incubation medium (single‐point assay). Due to the much greater stability of colchicine binding capacity under the conditions described, multiple time‐point assays (time‐decay method) were not necessary for accurate determination of CBP in brain samples, as shown by the agreement of results obtained using the two methods to measure CBP in C129F1 hybrid mouse brains at different stages of development. In this study, the highest concentrations of CBP (millimoles of colchicine bound per milligram of total protein) were observed in the 160,000g supernatant and pellet of newborn‐brain homogenate. The CBP concentrations in these two fractions were approximately twice those observed in the earliest stage measured (13.5 days gestation) and in the 11‐month‐old adult. However, CBP concentration, in terms of millimoles of colchicine bound per gram of brain wet weight, reached a maximum at the end of the 1st week after birth. Between 17.5 days gestation and the end of the 1st postnatal week, more CBP accumulated in the pellet fraction than in the supernatant. Tse C. and Doherty R. A. An improved DEAE‐cellulose filter assay for colchicine binding protein (during mouse brain development). J. Neurochem.35, 767–774 (1980).
The Effects of Various Incubation Temperatures, Particulate Isolation, and Possible Role of Calmodulin on the Activity of the Base Exchange Enzymes of Rat Brain
Authors: Buchanan Alfred G. , Kanfer J. N. 
Published: October 2006

Abstract:The involvement of calmodulin in the choline, ethanolamine, and serine exchange activities of rat brain microsomes was investigated. Calmodulin stimulated choline exchange activity to a greater extent than ethanolamine and serine exchange activities. The three base exchange activities were inhibited by antipsychotic drugs believed to prevent calmodulin interaction, but not by calmodulin‐binding protein. The solutions employed for tissue homogenization and subsequent isolation of microsomes greatly influenced the base exchange activites. The process of resuspending isolated microsomes and recentrifugation, or “washing,” produced major losses of detectable activity. The base exchange enzyme activities were maximal at 45°, and Arrhenius plots revealed a common transition temperature of 31°. The activation energies for the base exchange reactions decreased at temperatures above the observed transition temperature. Kinetic data, Km and Vmax, for the base exchange activities at 27, 37, and 45° are presented. Buchanan A. G. and Kanfer J. N. The effects of various incubation temperatures, particulate isolation, and possible role of calmodulin on the activity of the base exchange enzymes of rat brain. J. Neurochem.35, 814–822 (1980).
Comparative Analysis of Rapidly Transported Axonal Proteins in Sensory Neurons of the Frog and Rat
Authors: Neale Joseph H. , Formant David S. , Shibla Deborah B. , Shortell Sheryl A. 
Published: October 2006

Abstract: 35S‐labeled proteins carried by fast axonal transport in sciatic sensory axons of bullfrog and rat were separated electrophoretically on discontinuous polyacrylamide gradient slab gels. In contrast to the previously reported similarity in the electrophoretic profiles of rapidly transported proteins from functionally different neurons, we have found that there is very little correspondence in the profiles of these proteins in functionally similar neurons from two widely studied species. We also found very little correspondence between the two species in the profiles of locally synthesized sciatic nerve protein. The results demonstrate the difficulty inherent in comparing the electrophoretic profiles obtained using these two model systems for the study of rapidly transported axonal proteins. In particular, relationships between the major rapidly transported proteins in the two species could_not be analyzed with this technique.
The Response of Ornithine Decarboxylase During Neuronal Degeneration and Regeneration in Olfactory Epithelium
Authors: Rochel S. , Margolis F. L. 
Published: October 2006

Abstract:Mature olfactory neurons are continually replaced from a population of progenitor cells. Olfactory nerve section, bulbectomy, or treatment with certain chemicals induces degeneration of olfactory neurons followed in some cases by regeneration. Ornithine decarboxylase (ODC) activity was measured in mouse olfactory tissues as an indicator of cellular regeneration. ODC activity in olfactory tissue (0.2–0.4 nmol/mg protein/h) is 10‐30 times higher than in a variety of other cerebral tissues. Within 3 h after unilateral olfactory nerve section, ODC activity in the epithelium declines to 50% of control followed by a slow return to basal activity by 6 days. In the same animals, ODC activity increases severalfold in bulb (1 day) with a gradual decline to normal (9 days). Except for an early transient increase, the effects of unilateral bulbectomy on epithelial ODC activity are similar to those seen after nerve section. The changes in ODC activity following intranasal irrigation with 10 mm‐colchicine also closely mimic those seen after nerve section. The effects of intranasal irrigation on ODC activity with 0.5% Triton X‐100 or 0.17 m‐ZnSO4 are more complex. Thus, when the mature neuronal population is degenerating after surgery or chemical treatments, ODC activity decreases in the epithelium. The subsequent increase of ODC activity prior to reconstitution of the mature neuronal population probably reflects the regeneration mechanism of the olfactory epithelium. The increase of ODC activity in the olfactory bulb after nerve section is best interpreted as a cellular injury response. These alterations in ODC activity in olfactory tissues after chemical and surgical treatments constitute the earliest biochemical events observed in these tissues in response to cellular damage.