bluuebunny/crossref_metadata_2025_split huggingface dataset:
INTRACELLULAR LOCALIZATION OF PHENOL SULPHOTRANSFERASE IN RAT BRAIN
Authors: Jansen G. S. I. M. , Vrensen G. F. J. M. , Van Kempen G. M. J. 
Published: October 2006

Abstract—The intracellular localization of phenol sulphotransferase in rat brain was studied The distribution pattern found after differential centrifugation closely resembles that of lactate dehydrogenase and does not change during postnatal development. The distribution of the enzyme in discontinuous and continuous sucrose gradients, however, shows a deviation from the lactate dehydrogenase pattern and a shift towards a higher sucrose concentration during development. In the adult the phenol sulphotransferase coincides with monoamine oxidase, succinate dehydrogenase and β‐glucuronidase. Disruption experiments, purification of mitochondria and electron microscopy exclude localization of phenol sulphotransferase in mitochondria. These studies support the idea of phenol sulphotransferase as a cytoplasmic enzyme with a preferential binding to or localization in oligodendroglial cells or, more probably, a specific type of synaptosomes.
INTERRELATIONSHIPS AMONG THE LEVELS OF ATP, ADENOSINE AND CYCLIC AMP IN INCUBATED SLICES OF GUINEA‐PIG CEREBRAL CORTEX: EFFECTS OF DEPOLARIZING AGENTS, PSYCHOTROPIC DRUGS AND METABOLIC INHIBITORS
Authors: Huang M. , Daly J. W. 
Published: October 2006

Abstract—Adenine nucleotides of guinea‐pig cerebral cortical slices were labelled during a 40 min incubation with [14C]adenine. Subsequent incubation of cortical slices with depolarizing agents, such as veratridine, ouabain, batrachotoxin and high concentrations of potassium ions, or with certain psychotropic drugs such as chlorpromazine, chlorimipramine or prenylamine resulted in a reduction in both endogenous and radioactive ATP, accompanied by a marked increase in levels of both endogenous and radioactive cyclic AMP. Reduction of ATP levels during incubation with depolarizing agents, such as veratridine, is probably associated with increased activity of membranal Na+‐K+‐activated ATPase, while the reduction elicited by psychotropic drugs is proposed to be due to inhibition of mitochondrial synthesis of ATP. With both classes of compounds reduction of ATP levels results in enhanced formation and efflux of adenosine which stimulates formation of cyclic AMP from intracellular ATP in the compartments of brain slices which contain the cyclic AMP‐generating systems. Certain classical metabolic inhibitors such as 2,4‐dinitrophenol, azide, 1,2‐naphthoquinone‐8‐sulfonate and cyanide also reduce ATP levels and in the case of 2,4‐dinitrophenol, cyanide, and azide elicit small but significant accumulations of cyclic AMP. With certain metabolic inhibitors reduction of ATP within the cyclic AMP generating compartments would appear to prevent or reduce the accumulation of cyclic AMP elicited by amines, adenosine or veratridine.
ELECTROPHORETIC STUDY OF 5‐HYDROXYTRYPTOPHAN DECARBOXYLASE FROM BRAIN AND LIVER IN SEVERAL SPECIES
Authors: Cavalli‐Sforza L. L. , Santachiara S. A. , Wang L. , Erdelyi E. , Barchas J. 
Published: October 2006

Abstract—An electrophoretic investigation in acrylamide gels of 5‐hydroxytryptophan decarboxylase, obtained mostly from mouse, rat, and beef brain and also from beef and human liver, showed electrophoretic differences between species. With the exception of the rat, only one molecular species was found (the same in beef brain and liver). In the rat, polymers form spontaneously and are, at least in part, disaggregated by urea and by triton. Mouse‐rat or beef‐rat molecular hybrids form in the admixtures. No electrophoretic differences were found in five mice strains that were investigated. Techniques of electrophoretic analysis and of assay of 5‐hydroxytryptophan decarboxylase are described, which can be easily applied to other enzymes, provided a substrate is available in radioactive form.
METABOLIC ACTIVITY OF CNS PROTEINS IN RATS AND MONKEYS WITH EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS (EAE)
Authors: Smith Marion Edmonds , Rauch Helene C. 
Published: October 2006

Abstract—The metabolic activity of proteins from myelin and non‐myelin fractions of slices of lesions in monkey brains and in spinal cords of Lewis rats with acute experimental allergic encephalomyelitis was investigated using [1‐14C]leucine as a protein precursor. The uptake in vitro of [1‐14C]leucine into the monkey EAE lesions was greatly increased in both the myelin and non‐myelin fractions. Similar findings were made in spinal cord slices of the EAE rat with an average specific activity 341 per cent of control measured in proteins of purified myelin and 415 per cent of control in the non‐myelin protein. The increased uptake appeared with the onset of paralytic symptoms 10–14 days after injection. The increased uptake did not appear to be a result of an increased amino acid pool size as measured with uniformly labelled l‐leucine, valine, arginine and phenylalanine. The increase in specific activity of the myelin protein of the EAE rats was shown to be associated with the peaks characteristic of myelin protein when separated on polyacrylamide gels and the serial slices counted. Most of the radioactivity of both the control and EAE myelin protein migrated with the high molecular weight fraction, and the largest increase in radioactivity in myelin protein appeared in this fraction. Some increase in specific activity was also found in the basic and proteolipid proteins. Four different guinea‐pig antigens were used to induce EAE: whole spinal cord, purified basic protein, purified myelin and basic protein + cerebroside. All caused paralytic symptoms and greatly increased incorporation in vitro of [1‐14C]leucine into spinal cord proteins. The incorporation of [1‐14C]leucine into slices of the inguinal and popliteal lymph nodes of the EAE and Freund's adjuvant control rats were measured and compared with the incorporation into the spinal cord non‐myelin fractions. The specific activity of lymph node proteins was of the order of 10 × that of the non‐myelin protein of the control spinal cord. Invasion of a moderate number of cells of the order of activity of these lymph nodes could account for the large increase in rate of protein synthesis in the EAE nervous tissue. It is concluded that much of the increased protein synthesis could be due to the inflammatory cells, although a small amount of the total increase appears to be associated with myelin protein. Other changes in metabolism of the CNS tissue of the EAE rat include a lower rate of lipid synthesis and a decreased activity of the tricarboxylic acid cycle.
PROTEINS OF HUMAN BRAIN TISSUE OBTAINED DURING SURGICAL PROCEDURES
Authors: Cain D. F. , Ball E. D. , Dekaban A. S. 
Published: October 2006

Abstract— A series of normal and abnormal brain tissues were obtained during surgical procedures; adjacent portions were evaluated histologically or extracted with dilute buffer. The proteins were separated in acrylamide gels using electrophoresis and isoelectric focusing. Twelve of the patients showed a very similar distribution of the proteins on electrophoretic separation referred to as the ‘typical’ pattern. This group includes all of the histologically normal specimens, and in addition, one mild gliosis, two cases of juvenile lipidosis, one mucopolysaccharidosis and one Unverricht epilepsy. Remarkably little variability in the electrophoresis gel pattern was found in a series of five pairs of histologically normal gray and white matter samples. An increased density of several bands was apparent in extracts of gray matter when compared with corresponding white. No differences which could be correlated with the different areas of the cortex were seen.Six of the patients showed gel patterns different from the ‘typical’ pattern. One of these (glioblastoma) differed only in the increase in band 9. Another glioblastoma showed a virtual absence of nearly all of the brain proteins usually found in the gels. Two astrocytomas and one surgical scar specimen showed a very dense protein band (No. 15) and a novel minor protein component, band 20, while one case of SSPE showed only the heavy band in the area of band 15. The content of band 5 was reduced in those specimens which presented a dense band 15. The pronounced increase in band 15 and band 20 appears to correlate with the marked increase in astrocytic elements in these three patients.
NEURONAL CELL BODY ENRICHED AND GLIAL CELL ENRICHED FRACTIONS FROM YOUNG AND ADULT RAT BRAINS: PREPARATION AND MORPHOLOGICAL AND BIOCHEMICAL PROPERTIES
Authors: Nagata Y. , Mikoshiba K. , Tsukada Y. 
Published: October 2006

Abstract—A technique for separating neuronal and glial cell fractions in bulk from rat brain has been developed which does not use any digestive enzymes. Carbonic anhydrase, S‐100 protein and 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase were associated with the glial fraction. Glutamate and aspartate were the most abundant free amino acids; the neuronal fraction was richer in GABA and glycine than the glial fraction. Both d‐glutamate and potassium ions were actively accumulated in each fraction during aerobic incubation. Na,K‐ATPase was higher in the glial fraction; its activity, especially in the glial fraction, increased rapidly from the 10th to the 20th day after birth. Lactate dehydrogenase showed higher activity in the neuronal than in the glial fraction during early development; its isozyme pattern in each fraction was similar to that of whole brain. Acetylcholine esterase had its maximum activity around the 15th day in both fractions. Limitations of this bulk separation technique are discussed.
FLUID SPACES OF SYNAPTOSOME BEDS
Authors: Heaton G. M. , Bachelard H. S. 
Published: October 2006

Abstract—The fluid spaces of synaptosome beds were estimated by vol. measurement and also by a combination of chemical and enzymic analyses. The extra‐synaptosomal space of the beds was concluded to be about 80 per cent of their total vol. Beds prepared by conventional techniques after sucrose density‐gradient centrifugation were found to contain 0‐08 M‐sucrose within the synaptosomes.
THE MECHANISM OF THE EXCLUSION OF SODIUM IONS AND THE CONCENTRATION OF POTASSIUM IONS BY GUINEA‐PIG CEREBRAL CORTEX SLICES
Authors: Hillman H. , Stollery Susan , Joanny P. 
Published: October 2006

Abstract—Guinea pig cerebral slices were incubated in oxygenated Krebs‐Ringer bicarbonate glucose saline for periods of 1 s to 60 min, and their swelling and Na+ and K+ cone were measured. The swelling was at the rate of 8 per cent for the 1st min, and 0·8 per cent for the next 29 min; it fell significantly during the subsequent 30 min (P= 0·05). The Na+ and K+ concn in the tissue fluctuated during the 1st min of incubation, but the Na+ concn had risen to a mean of 108 mm after 1 min incubation and the K+ concn had fallen to a mean of 52 mm by 3 min. The concentrations of these cations did not change significantly after these times. Cerebral slices were also incubated for 30 min in isotonic media modified such that Na+, + K+, Na++ choline+, or K++ choline+ always added up to 150 mm. It was found that about half of the swelling (20‐25 per cent) was independent of the Na+ or K+ concn and a further 20‐25 per cent of the swelling varied with the cations only if Na+ and K+ were both present and was a function of the K+ concn in the medium (0·15 per cent m‐mol). The Na+ concn in the tissue was a mean 8·4 mm after incubation in a Na+‐free medium and 7·1 mm in K+ after incubation in a K+‐free medium. Cerebral slices in the presence of Na++ K+ excluded one molecule of Na+ for every four molecules in the incubating medium; they accumulated K+ from the medium until the concn in the medium exceeded 130 mm.
METHYLASES OF MYELIN BASIC PROTEIN AND HISTONE IN RAT BRAIN
Authors: Miyake M. 
Published: October 2006

Abstract—The two enzymes methylating myelin basic protein and histone were purified 170‐ and 250‐fold respectively from the cell sap fraction of rat brain. These enzymes methylated only arginine residues of the two proteins. The enzyme activities were present in all organs tested. Testis has the highest, brain a moderate and liver the lowest activity. Most of the activities were present in the cell sap fraction in brain, liver and testis. Methylation of myelin basic protein and histone was examined in both the cell sap and solubilized nuclear fraction of rat brain during life span after birth. The myelin basic protein methylating activity in the cell sap fraction increased during myelination. Histone methylase from the nuclear fraction was highest at birth and dropped rapidly thereafter. The other activities remained unchanged. The natural occurrence of NG‐mono‐ and NG,NG‐dimethylarginine residues in histones prepared from rabbit liver was demonstrated.
EFFECT OF UNILATERAL VISUAL DEPRIVATION AND VISUAL STIMULATION ON THE ACTIVITIES OF ALKALINE PHOSPHATASE, ACID PHOSPHATASE, Na+−K+ ACTIVATED Mg2+ CATALYSED ADENOSINE TRIPHOSPHATASE AND ON THE CONTENT OF SODIUM AND POTASSIUM IONS OF THE OPTIC LOBE OF ADULT PIGEON
Authors: Chakrabarti T. , Daginawala H. F. 
Published: October 2006

Abstract—A study was made of the effects of unilateral visual deprivation and stimulation upon the activities of alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), Na+‐K+ activated Mg2+ catalysed ATPase (EC 3.6.1.4) and upon the Na+ and K+ contents of the optic lobe of adult pigeon (Columba livia). Visual deprivation was achieved by eyelid suturing or by enucleation and maintained for 1–9 weeks. Unilateral visual stimulation was maintained for 75 min following 72 h of darkness. A statistically significant increase in the activity of alkaline phosphatase activity was observed in the optic lobe after unilateral visual deprivation whereas unilateral visual stimulation resulted in the opposite effect. Acid phosphatase activity was found to be unchanged under all experimental conditions. Na+‐K+ ATPase activity was found to increase significantly following unilateral visual stimulation and following eyelid suturing in the corresponding optic lobes; unilateral enucleation resulted in a decrease in the Na+‐K+ ATPase activity. An increase in the enzyme activity was found to be associated with an increase in the level of Na+‐ion and a decrease in the level of K+‐ion, and vice versa.
SHIFTS IN UBIQUINONE REDOX STATUS OF RAT BRAIN IN VITRO WITH CATIONIC STIMULATION
Authors: Klicpera J. A. , Hoffmann P. C. 
Published: October 2006

Abstract–Changes in respiratory rate, ubiquinone (Q) redox status, lactate and pyruvate levels in chopped rat telencephalon were studied after cationic stimulation of respiration. When chopped telencephalon was incubated with glucose as substrate, increasing the K+ concentration from 5 mm to 55 mm was associated with a 57% increase in the respiratory rate and a reduction in Q redox status from 76% oxidized to 64% oxidized. Lactate increased by over 200%. Substitution of pyruvate for glucose with 5 mm‐K+ resulted in a respiratory rate that was 78% of that seen with glucose and 55 mm‐K+. Increasing K + from 5 mm to 55 mm increased the respiratory rate by only 6%, with pyruvate as substrate. Q underwent a reduction that was half that seen with glucose. Ouabain largely prevented the K +‐induced increase in respiratory rate with glucose as substrate, but Q was still reduced by 5 percentage points while lactate and pyruvate were unchanged. When respiration was uncoupled with 2,4‐dinitrophenol, increasing the K+ concentration from 5 mM to 55 mm had no further effect on any of the metabolic parameters measured. Deletion of Ca2+ from the medium resulted in an increase in respiration of 18%, but neither the Q redox status nor the levels of lactate or pyruvate were significantly changed. The results demonstrate that the K+‐induced stimulation of respiration results from a coordinated metabolic response whereas the stimulation of respiration associated with Ca2+ depletion is probably mediated through ion fluxes at the cell membrane and activation of Na+‐K+‐activated ATPases.
METABOLISM OF POLYAMINES IN MOUSE NEUROBLASTOMA CELLS IN CULTURE:1 FORMATION OF GABA AND PUTREANINE
Authors: Kremzner L. T. , Hiller J. M. , Simon E. J. 
Published: October 2006

Abstract—Polyamine metabolism of mouse neuroblastoma cells grown in culture was studied with special reference to the synthesis of GABA from putrescine and putreanine from spermidine. This study shows that neuroblastoma cells in the presence of a complete culture medium containing calf serum readily metabolized [14C]putrescine to GABA; the rate of synthesis is similar to the rate of synthesis of spermidine from putrescine. In the absence of serum the conversion of putrescine to GABA is minimal. In the presence of serum GABA formation is completely inhibited by the diamine oxidase inhibitor aminoguanidine. GABA synthesis does not occur in the absence of cells. The GABA synthesized is not readily metabolized to succinate or homocarnosine. Mouse neuroblastoma cells metabolized [14C]ornithine to putrescine, GABA, and spermidine. Spermidine was metabolized to putrescine, putreanine and spermine.
THE BIOSYNTHESIS OF CHOLESTEROL AND OTHER STEROLS BY BRAIN TISSUE: DISTRIBUTION IN SUBCELLULAR FRACTIONS AS A FUNCTION OF TIME AFTER INJECTION OF [2‐14C]MEVALONIC ACID, SODIUM [2‐14C]ACETATE AND [U‐14C]GLUCOSE INTO 15‐DAY‐OLD RATS
Authors: Jones J. P. , Rios A. , Nicholas H. J. , Ramsey R. B. 
Published: October 2006

Abstract—The distribution of [14C]‐labelled material into subcellular fractions of 15‐day‐old rat brain was studied at 2 and 24 h following intraperitoneal and intracerebral injection of [2‐14C]sodium acetate, [U‐14C]glucose and [2‐14C]mevalonic acid respectively. The total quantity of labelled isoprenoids in the brain was, except for glucose, greater when the precursor was administered intracerebrally. The intraperitoneal route was more advantageous in the case of [U‐14C]glucose. The subcellular distribution of both labelled total isoprenoid material and sterol was distinct for each labelled precursor. Intracerebrally injected [U‐14C]glucose at both time periods studied suggested no dominance of labelling in any fraction. After intraperitoneal injection of [U‐14C]glucose the microsomes were more prominently labelled. Both methods of administration of sodium [2‐14C]acetate resulted in heavy labelling of the myelin fraction after 24 h. The total labelled isoprenoids resided mainly in the microsomes 24 h after injection of [2‐14C]mevalonic acid. Labelled sterol was found to be localized more in the myelin and microsomal fractions for all three precursors than was the labelled total isoprenoids. Depending on the type of experiment to be conducted, each of these precursors can give different results, which must be interpreted accordingly.
INJECTION OF 6‐HYDROXYDOPAMINE AND HYDROGEN PEROXIDE INTO THE SUBSTANTIA NIGRA AND LATERAL VENTRICLE OF THE CAT: SPECIFIC AND NONSPECIFIC EFFECTS ON STRIATAL BIOGENIC AMINES1
Authors: Stahl S. M. , Daniels A. C. , Derda D. , Spehlmann R. 
Published: October 2006

Abstract—Attempting to clarify the mechanism by which intracerabral injection of 6‐hydroxydopamine (60HDA) reduces catecholamines in the caudate nucleus (CN), we have tested two hypotheses: (1) 60HDA specifically attacks catecholaminergic neurons; (2) 60HDA liberates hydrogen peroxide (H2O2) which destroys neurons indiscriminately. To this end, we have injected high or low doses of 60HDA or equimolar amounts of H2O2 stereotaxically into the substantia nigra (SN) or the lateral ventricle of cats and have placed electrocoagulative lesions in the SN. We determined the CN levels of dopamine (DA), norepinephrine (NE) and serotonin (5HT) 7‐10 days later. Nigral injections of high doses (8 μ mol) of either agent or low doses (80 nmol) of 60HDA decreased both DA and NE and induced similar histologic damage in the SN with neuronal drop‐out at the periphery of the lesions. Injection of 80 nmol of H2O2 into the SN did not decrease CN amine levels and did not produce histologic damage in the SN. Electrocoagulation of the SN decreased CN DA and NE, but the histologic lesions failed to show any peripheral neuronal drop‐out. Ventricular injections of high doses (16 μmol) of 60HDA or H2O2 reduced not only DA and NE but also 5HT levels in the ipsilateral CN. Low intraventricular doses (0‐16 μmol) of 60HDA decreased only DA and NE without affecting 5HT levels in the CN whereas 0.16 μmol of H2O2 had no effect on any of the CN amines. The catecholamine‐depleting effects of low doses (80 nmol) of 60HDA were significantly potentiated by inhibiting brain monoamine oxidase by 90 percent or more at the time and site of injection of 60HDA. These results suggest that the extracellular liberation of H2O2 from 60HDA could explain some possibly nonspecific effects of high doses of 60HDA; at lower doses, however, 60HDA may act via selective uptake into catecholaminergic neurons with subsequent intracellular release of H2O2.
A RELATIONSHIP OF N‐ACETYLASPARTATE BIOSYNTHESIS TO NEURONAL PROTEIN SYNTHESIS12
Authors: Clarke D. D. , Greenfield S. , Dicker E. , Tirri L. J. , Ronan E. J. 
Published: October 2006

Abstract—A detailed time study of the incorporation of label from sodium‐[1‐14C]acetate, [1‐14C]ethanol, and [2‐14C]glucose into the aspartyl moiety of N‐acetylaspartic acid (NAA) was conducted. As expected the specific activity of aspartate increased rapidly with time and peaked within 15‐20 min after which it fell sharply; but significantly, that of the aspartyl moiety of NAA rose very slowly even after the specific activity of aspartate had fallen to less than 1 per cent of the peak values.A rat brain microsomal free supernatant preparation was shown enzymatically to incorporate label from sodium‐[1‐14C]acetate into the t‐RNA fraction from which was isolated N‐[1‐14C]acetylaspartic acid. From these observations we were inclined to speculate that NAA‐t‐RNA may serve as an initiator of neuronal protein synthesis.
THE VISUALIZATION OF CONCANAVALIN‐A BINDING SITES IN THE INTERPERIOD LINE OF RAT SCIATIC NERVE MYELIN
Authors: Wood J. G. , McLaughlin Barbara J. 
Published: October 2006

Abstract—The plant lectin, Concanavalin A (Con A), is used in combination with a peroxidase‐labelling technique to visualize carbohydrates in myelin. The major myelin glycoprotein seen by polyacrylamide electophoresis binds Con A. Thin slices of sciatic nerve bind Con A in the interperiod line of the myelin. These data suggest that the glycoprotein may be located at the interperiod line.
CATECHOLAMINES IN SYMPATHETIC GANGLIA OF RAT: EFFECTS OF DEXAMETHASONE AND RESERPINE1
Authors: Koslow S. H. , Bjegovic M. , Costa E. 
Published: October 2006

Abstract—The superior cervical sympathetic ganglion of rats contains a finite amount of epinephrine all of which is of ganglionic origin. Treatment of new‐born rats with dexamethasone for 8 days results in a 112‐fold increase in the epinephrine concentration, whereas the norepinephrine and dopamine are increased by only 1·4‐ and 1·9‐fold respectively. This epinephrine increase in newborn rats is reversible if treatment is discontinued, and it fails to occur in adult animals. The epinephrine store of normal and dexamethasone treated animals is resistant to the depletion by reserpine. There is no increase in the epinephrine content in organs innervated by axons emanating from the ganglion. The data presented support the localization of epinephrine in small intensely fluorescent cells in the ganglion and we propose that epinephrine may be released from these cells and function as a modulator of ganglionic transmission.