bluuebunny/crossref_metadata_2025_split huggingface dataset:
KINETICS OF THE BIOSYNTHESIS OF PHOSPHOLIPIDS IN NEURONS AND GLIAL CELLS ISOLATED FROM RAT BRAIN CORTEX
Authors: Freysz L. , Bieth R. , Mandel P. 
Published: October 2006

Abstract—32P incorporation into different rat‐brain cortex neuronal and glial phospholipids was investigated. The half life of each compound was measured.Neuronal phospholipids had a faster turnover than glial phospholipids. Phosphatidyl‐inositol and choline plasmalogen had the fastest, diphosphatidylglycerol the lowest turnover in both cell‐types. Phosphatidylcholine, ethanolamine phospholipids and serine phospholipids had turnover intermediate with that of the previously described compounds.Turnover of neuronal sphingomyelin was similar to that of phosphatidylcholine, whereas in glial cells it was much lower.
RELATIONSHIPS BETWEEN ENERGY RESERVES AND FUNCTION IN RAT SUPERIOR CERVICAL GANGLION1
Authors: Härkönen Matti H. A. , Passonneau Janet V. , Lowry O. H. 
Published: October 2006

Abstract—Major components of the energy reserves of the isolated superior cervical ganglion (ATP, phosphocreatine, glucose, glycogen and lactate) were measured under aerobic and anaerobic conditions. Complete anaerobiosis was maintained by incubation in mineral oil through which N2 had been bubbled. From the initial rate of change in the energy reserves, a metabolic rate was calculated which would be equivalent to the consumption of 93 m‐moles of O2 per kg per hour. Under aerobic conditions (oxygenated moist chamber) a similar metabolic rate was calculated. In contrast to the anaerobic state, initial energy expenditure was almost exclusively at the expense of glucose. Continuous supramaximal stimulation in O2 increased energy expenditure by a factor of three; both glucose and glycogen were utilized from the outset, and lactate accumulated in the initial periods.Ganglionic transmission failed in both resting and stimulated states in spite of the continued presence of very substantial levels of ATP and phosphocreatine. Failure seemed to be associated not with ATP depletion but rather with the complete disappearance of glucose and glycogen.
COMPARISON OF THE FATTY ACIDS OF LIPIDS OF SUBCELLULAR BRAIN FRACTIONS
Authors: Kishimoto Y. , Agranoff B. W. , Radin N. S. , Burton R. M. 
Published: October 2006

Abstract— Rat brain grey and white matter were fractionated to yield myelin, nerve terminal, synaptic vesicle, nerve terminal ‘ghost’, and microsomal fractions of white and grey matter. Ester‐type glycolipids were found in all fractions except myelin, while cerebrosides occurred in significant concentrations only in myelin and white microsomes. Comparison of the fatty acid profile of the ethanolamine‐ and serine‐containing phospholipids showed marked differences between myelin and the particles from grey matter, while the microsomes of white matter were of intermediate composition. Docosahexaenoic acid, a minor acid in myelin, was a major fatty acid in microsomes of grey and white matter. The fatty acid composition of sphingomyelin was distinctly different in the fractions derived from grey and white matter, clustering about stearate and nervonate in the latter, but only about stearate in the grey. Marked differences in the positional distribution of fatty acids were seen within phosphatidyl choline from myelin and nerve terminals. Ribonucleic acid was found in nerve terminal and synaptic vesicle fractions. The sphingosine found in the ganglioside from microsomes of both grey and white matter was similar with respect to distribution of the C18 and C20 homologues.The possibility is discussed that microsomes furnish characteristic lipids for the synthesis or renewal of specific membranes, and that these lipids are accumulated somewhat before being released.
BINDING OF d‐[DIMETHYL14C]TUBOCURARINE, ACETYLCHOLINESTERASE AND PROTEOLIPIDS IN SUBCELLULAR MEMBRANES OF CEREBRAL CORTEX OF THE DEVELOPING RAT1
Authors: Gömez C. J , Pasquini Juana M , Soto E. F , Robertis E. De 
Published: October 2006

Abstract— The cerebral cortex of rats at postnatal ages of 5,15,30 and 50 days was homogenized and fractionated to separate the crude mitochondrial fraction. This fraction was osmotically shocked and the Mi fraction and subfractions were separated. The variations with age in the morphological composition of subfractions M1 0·8, Mi 1·3 and M1p were studied under the electron microscope. Because of the changes observed in the various fractions the need for such type of control is stressed.The changes in total protein and proteolipid‐protein of the fractions at different ages, as well as the acetylcholinesterase activity and the binding of d‐[dimethyl−14C]tubocurarine were studied. The results obtained were interpreted on the basis of the important morphogenetic changes that the cerebral cortex undergoes postnatally. The progressive and parallel increase in acetylcholinesterase and in the binding of d‐[dimethyl‐14C]tubocurarine to proteolipids of fraction Mi 1·3, suggest a close relationship between these two events and the development of the cholinergic synapses.
A LIGHT‐SCATTERING TECHNIQUE FOR THE STUDY OF THE PERMEABILITY OF RAT BRAIN SYNAPTOSOMES IN VITRO
Authors: Keen P , White T. D 
Published: October 2006

Abstract— (1) Swelling of synaptosomes was measured spectrophotometrically by recording changes in extinction at 520 nm.(2) Synaptosomes behaved as osmometers in NaCl solutions. When the tonicity of the medium was changed, synaptosome volume changed in accordance with Boyle and van't Hoff's Law. These changes were reversed on restoring the tonicity of the medium.(3) The rate at which a solute entered the synaptosome was determined from the rate of swelling in the presence of that solute. Permeability of synaptosomes to non‐electrolytes was in the order glucose ≪ glycerol < thiourea = formamide < propylene glycol = dimethylsulphoxide.(4) Synaptosomes were freely permeable to ammonium and acetate ions and impermeable to Ca2+, Mg2+, PO42−, SO42− and oxalate ions.
CHANGES WITH AGE IN WATER AND EXTRA‐CELLULAR SPACE IN INCUBATED BRAIN TISSUE
Authors: Levi G , Lattes Maria G 
Published: October 2006

Abstract— (1) Incubation in physiological saline at 37º caused brain slices from chick embryos to lose water (shrink), whereas slices from young chicks gained water (swell). Shrinkage decreased with age in embryonic brain, and swelling increased with age in chick's brain.(2) Incubation at 0º diminished shrinkage in 8‐day old embryos, caused an increasing degree of swelling in older embryos, and enhanced swelling in young chick's brain slices.(3) Inulin equilibrated more rapidly with tissue water in embryonic than in young adult brains. Measured ‘inulin space’ values at 37º changed little with age, whereas 0º‘inulin space’ values significantly decreased with age. Calculated zero time ‘inulin space’ values also decreased with age.(4) The measured ‘inulin space’ at 0º was larger than that measured at 37º (but not of the calculated zero time ‘inulin space’) in young embryos, then became progressively smaller, so that in young chicks the situation was reversed.(5) The calculated extracellular space ranges from about 37 per cent (8‐day old embryos) to about 14 per cent (15‐day old chicks).(6) Incubation in the absence of glucose had more effect on brain slices from young chicks than from embryos. The opposite was true when a hypotonic medium or a medium containing d‐glutamate was used.
EFFECTS OF SHOCK AND ANOXIA ON NUCLEOTIDES AND CREATINE PHOSPHATE IN THE ISOLATED BRAIN OF THE DOG1
Authors: Minsker D. H. , Gilboe D. D. , Stone W. E. 
Published: October 2006

AbstractSurgically isolated canine brains were maintained with compatible donor blood from an extracorporeal perfusion system. Small samples of frozen cerebral cortex were removed with a newly‐developed Freon cryoprobe and were analysed for acid‐soluble nucleotides, creatine phosphate and inorganic phosphate. Most animals were in the early stages of shock unless they had received preoperative α‐adrenergic blockade with phenoxybenzamine hydrochloride (Dibenzyline). Values for high‐energy phosphates were in the normal range only when the animal had been premedicated with phenoxybenzamine hydrochloride. During a 4‐min period of anoxia (induced by blood which had been equilibrated with 95% N2 and 5% CO2), the cerebral cortex rapidly became iso‐electric, and the levels of creatine phosphate and ATP decreased concomitantly with increases in levels of ADP and Pi. These electrical and chemical changes were rapidly and completely reversed by reoxygenation. The levels of high‐energy phosphates provide a sensitive criterion of functional adequacy that may be more readily quantitated than cerebral electrical activity (EEG). EEG recovery did not correlate closely with rephosphorylation.
EFFECTS OF DOPAMINE, GAMMA‐AMINOBUTYRIC ACID AND 5‐HYDROXYTRYPTAMINE ON INCORPORATION OF 32P INTO PHOSPHATIDES IN SLICES FROM THE GUINEA PIG BRAIN1
Authors: Hokin Mabel R. 
Published: October 2006

Abstract(1) Dopamine–In slices from guinea pig corpus striatum, dopamine significantly inhibited incorporation of 32P into phosphatidylethanolamine‐plus‐phosphatidylserine at a concentration of 0001 mM, and into phosphatidylinositol and phosphatidylcholine at 001 mM. In eight areas of the guinea pig brain in which the effects of 01 mM‐dopamine were studied, the only significant increase in incorporation of 32P into phosphatides was into phosphatidic acid in the hypothalamus; there was significant inhibition of incorporation of 32P into phosphatidylcholine in cerebellar cortex and thalamus, and into phosphatidylethanolamine‐plus‐phosphatidylserine in the olfactory bulbs.(2) Gamma‐aminobutyric acid—In slices of guinea pig cerebral cortex, GABA (1 mM) significantly inhibited incorporation of 32P into only phosphatidic acid, diphosphoinositide and phosphatidylinositol and did not significantly affect the level or the specific activity of the nucleotide ∼P. GABA (10 mM), significantly inhibited incorporation of 32P into diphosphoinositide, phosphatidylinositol and phosphatidylcholine, and significantly lowered the specific activity of the nucleotide ∼P.(3) 5‐Hydroxytryptamine—In slices of guinea pig cerebral cortex, 5HT, (1 mM) significantly increased incorporation of 32P into phosphatidic acid; in a concentration of 10 mM, 5HT increased incorporation of 32P into phosphatidic acid four‐fold and into both diphosphoinositide and phosphatidylinositol two‐fold; other phosphatides were not significantly affected and the specific activity of the nucleotide ∼P was not significantly different. In eight brain areas studied, 5HT (10 mM) significantly increased incorporation of 32P into phosphatidic acid in all areas; into phosphatidylinositol in six areas (excepting cerebellar cortex and hypothalamus); and into diphosphoinositide in the olfactory bulbs, cerebral cortex, hypothalamus and corpus striatum. Incorporation of 32P into triphosphoinositide was not significantly affected in any area. Incorporation of 32P into phospha‐tidylethanolamine‐plus‐phosphatidylserine was significantly greater than the control in the olfactory bulbs and incorporation of 32P into phosphatidylcholine was significantly less than the control in the cerebellar cortex, olfactory bulbs and hypothalamus.(4) The possibility is discussed that increased incorporation of 32P into phosphatidic acid and/or phosphatidylinositol in response to neurotransmitters might be associated with excitatory, but not inhibitory, neurotransmission; and that inhibition of incorporation of 32P into various phosphatides may be associated with inhibitory neurotransmission or neuromodulation.
THE EFFECT OF METHIONINE SULPHOXIMINE ON THE INCORPORATION OF LABELLED GLUCOSE, ACETATE, PHENYLALANINE AND PROLINE INTO GLUTAMATE AND RELATED AMINO ACIDS IN THE BRAINS OF MICE
Authors: Van den Berg C. J. , Van den Velden J. 
Published: October 2006

Abstract—The incorporation of radioactivity from labelled glucose, acetate, phenylalanine and proline into glutamate, aspartate and glutamine was measured in mice treated with methionine sulphoximine and in the control animals. The labelled precursors were injected and their incorporation determined before the onset of convulsions. The incorporation of radioactivity from labelled glucose into the dicarboxylic amino acids was reduced, in particular the incorporation into glutamine. The incorporation of radioactivity from labelled acetate and phenylalanine into glutamate and aspartate was increased by methionine sulphoximine, while the incorporation into glutamine was not changed very much. The labelling of glutamine, relative to glutamate, was reduced with all precursors, indicating that glutamine synthetase was inhibited in vivo by methionine sulphoximine. It is very likely that methionine sulphoximine affects many aspects of energy metabolism in brain; in particular the metabolism of glucose seems to be inhibited, while the rate of conversion of substrates other than glucose seems to be increased.
THE EFFECT OF METHIONINE ON THE REGIONAL AND INTRACELLULAR DISPOSITION OF [3H]‐METHIONINE SULPHOXIMINE IN RAT BRAIN1
Authors: Ghittoni Nora E. , Ohlsson W. G. , Sellinger O. Z. 
Published: October 2006

Abstract—The intracellular disposition of the convulsant agent, methionine sulphoximine (MSO), administered as methyl‐labelled [3H]MSO, was examined in rat brain. Intraperitoneal (i.p.) and intrathecal (i.th.) routes were compared. The effect of simultaneous administration of methionine on the uptake, the regional distribution and the intracellular disposition of [3H]MSO was also assessed:(1) The peak uptake of i.p. [3H]MSO was at 2 h and amounted to about 1 per cent of the dose; the peak uptake of i.th. [3H]MSO was at 30 min post‐injection and amounted to 40 per cent of the administered dose. The uptake was effectively reduced when methionine was simultaneously administered.(2) The regional distribution of [3H]MSO as a function of time after injection revealed a rather uniform penetration of the entire brain by the drug. A maximum of 43 per cent of the tissue radioactivity was found in the cerebellum 2 h after i.p. injection, while 49 per cent accumulated in the extracortical portion of the brain 3·5 h after i.th. administration. Methionine did not affect the regional distribution of [3H]MSO.(3) Differential centrifugation of samples of cortex and cerebellum revealed an association of [3H]MSO with intracellular particulate fractions. Since closely similar proportions of MSO occurred in the crude mitochondrial and the microsomal fractions, these fractions were analysed further: (a) [3H]MSO was bound to nerve endings sedimenting at the 1·0 m–1·2 m‐sucrose interface; this binding was not abolished by prior increase of the endogenous cerebral methionine pool; and (b) [3H]MSO was released by subjecting the nerve endings to osmotic shock. However, the striking finding was that [3H]MSO could not be released from the nerve endings of the cerebellum from animals pre‐treated with methionine.(4) An association of [3H]MSO was observed with the membranes of the endoplasmic reticulum and specifically with its agranular component.(5)The results implicate the cerebellum as the primary target for MSO, in confirmation of the original observations of Lodin (1958).
AMINO ACID INCORPORATION IN VITRO INTO PROTEIN OF NEURONAL AND GLIAL CELL‐ENRICHED FRACTIONS
Authors: Blomstrand C. , Hamberger A. 
Published: October 2006

Abstract—Slices of rabbit cerebral cortex were incubated in the presence of labelled amino acids. Following incubation, neuron‐ and gliaenriched fractions were obtained by density gradient centrifugation and the TCA‐insoluble radioactivity determined. The protein‐bound radioactivity was five to six times higher in the neuronal‐enriched fraction than in the glial‐enriched fraction after incubation with tritiated leucine. The neuronal fraction incorporated also a number of other amino acids to a higher extent than the glial fraction (neuron/glia ratio 2·5‐6). A definite dependence of incorporation on the rate of oxygenation was demonstrated. The suppression of amino acid incorporation was more marked for the neuronal fraction than for the glial fraction during incubation in relative hypoxia. An increase of potassium concentration in the incubation medium enhanced the amino acid incorporation in both fractions. Low sodium levels decreased the incorporation. Puromycin inhibited incorporation to approximately 30 per cent of control for both fractions. Addition of cycloheximide and dinitrophenol resulted in greater inhibition of incorporation in the neuronal fraction than in the neuroglial fraction. Actinomycin D did not markedly affect the incorporation in any fraction. These results are discussed in relation to in vivo and in in vitro differences for transport and incorporation of amino acids.
HYDRAZIDE‐INDUCED SEIZURES AND CEREBRAL OF LEVELS γ‐AMINOBUTYRIC ACID: A RE‐EVALUATION
Authors: Abrahams Dawne E. , Wood J. D. 
Published: October 2006

Abstract—Data have been presented indicating that in chicks the time lag in the onset of seizures after the administration of hydrazides was not caused by a slow penetration of the convulsant agents into the brain. A correlation was evident between the rate of decrease in concentration of cerebral GABA and the susceptibility of chicks to hydrazide‐induced seizures. Earlier studies precluding a role for GABA in hydrazide‐induced convulsions were re‐examined.
GLUTAMATE AND RELATED AMINO ACIDS IN CAT SPINAL ROOTS, DORSAL ROOT GANGLIA AND PERIPHERAL NERVES
Authors: Duggan A. W. , Johnston G. A. R. 
Published: October 2006

Abstract—Of the free amino acids found in extracts of cat spinal roots, dorsal root ganglia and peripheral nerves, only glutamate was present in disproportionately high concentrations in those parts of the dorsal roots between ganglia and spinal cord. This distribution suggests that the high dorsal root levels of glutamate may result from synthesis in dorsal root ganglia and subsequent transport towards the spinal cord. Four excitant amino acids were detected in the extracts: aspartate, cysteate, cysteine sulphinate and glutamate. The unique regional distribution of glutamate is consistent with the proposed role of this amino acid as an excitatory transmitter at the terminals of primary afferent fibres.
LOCALIZATION OF TYROSINE TRANSAMINASE IN RAT BRAIN
Authors: Mark J. , Pugge H. , Mandel P. 
Published: October 2006

Abstract—The distribution of rat brain tyrosine transaminase was determined in brain regions and in subcellular fractions. The results indicate that brain tyrosine transaminase is predominantly a mitochondrial enzyme. Its localization on the inner mitochondrial membrane is suggested. The results are discussed in relation to the function of tyrosine as precursor of catecholamines in the central nervous system.
ENHANCEMENT OF BRAIN THIAMINE DIPHOSPHATASE ACTIVITY OF RATS BY INJECTION OF CHOLINERGIC DRUGS
Authors: Iwata H. , Inoue A. , Tomoi M. 
Published: October 2006

Abstract— The effects of cholinergic drugs on thiamine diphosphatase (TDPase) in rat brain, liver and kidney were studied to clarify the role of the enzyme in the central nervous system.Brain TDPase activity was markedly increased by intraperitoneal injection of a sub‐lethal dose of physostigmine, ambenonium or pentetrazol. These drugs also increased the activity in the kidney, but not liver. Strychnine, atropine, and scopolamine did not affect the activity of brain TDPase, but decreased the enzyme activity of liver and kidney. Physostigmine also increased the activity of brain thiamine monophosphatase.Brain TDPase activity reacheda maximum 30 minafterphysostigmine injection (1.0mg/kg). However, inhibition of brain acetylcholinesterase activity was greatest 45 min after physostigmine injection. The TDPase and AChE activities had both returned to normal values 60 min after the injection. The durations of these changes of TDPase and AChE activity corresponded to the duration of the tremor induced by physostigmine. The contents of total and phosphorylated thiamines in the brain but not in the liver or kidney were significantly reduced by physostigmine.The relationship between ACh and activation of TDPase activity by cholinesterase inhibitors is discussed.
DISTRIBUTION OF POLYSOMES IN MOUSE BRAIN TISSUE
Authors: Lerner M. P. , Wettstein F. O. , Herschman H. R. , Stevens J. G. , Fridlender B. R. 
Published: October 2006

Abstract— Polysomes were isolated from several different fractions of mouse brain tissue. After homogenization, the extract was centrifuged to yield a post‐mitochondrial supernatant fraction and a pellet fraction. Sucrose gradient analysis of the material in the post‐mitochondrial supernatant fraction indicated that 80 per cent of the ribosomes were present in polysomes and that little, if any, of the pellet fraction was present. Sucrose gradient analysis of the solution obtained after washing the pellet showed that very little polysomal material was present. The remaining pellet fraction was resuspended in a detergent mixture of deoxycholate‐Tween 40. Sucrose gradient analysis of the resulting detergent‐soluble solution indicated that large amounts of ribosomal material, in which 60–70 per cent of the ribosomes were associated in polysomes, were present.In brain tissue from young animals, 20 per cent of the polysomes were found in the post‐mitochondrial supernatant fraction whereas 80 per cent of the polysomes were released from the pellet fraction by detergent treatment. In contrast, in brain tissue from adult animals, 40 per cent of the polysomes were found in the post‐mitochondrial supernatant fraction, whereas 60 per cent of the polysomes were released from the pellet fraction by detergent treatment.
SUBCELLULAR FRACTIONATION OF GANGLIOSIDE SIALIDASE FROM HUMAN BRAIN
Authors: ÖHman R. 
Published: October 2006

Abstract—A subcellular fractionation was performed on forebrain cortex from three human brains and the fractions obtained were assayed for ganglioside sialidase and four p‐nitrophenyl glycohydrolases. Differences in the sedimentation patterns of the enzymes were observed. From 53 to 77 per cent of the recovered sialidase activity was found in the synaptosomal fraction, while the p‐nitrophenyl glycosidases were mainly recovered in the lysosome‐enriched fraction. Three possible interpretations of the sialidase sedimentation pattern are suggested: (1) The ganglioside sialidase is bound to the limiting membrane structure of the nerve ending. (2) The ganglioside sialidase is lysosomal, although bound to lysosomes of low density. (3) The enzyme occurs mainly in lysosomes primarily located in the nerve endings, being trapped under the formation of the synaptosomes.
PROTEIN SYNTHESIS IN VITRO IN RAT BRAIN AFTER SHORT‐TERM PROTEIN STARVATION AND REFEEDING
Authors: Von der Decken Alexandra , Wronski A. 
Published: October 2006

Abstract—Rats were fed a protein‐free diet for 4 or 6 days. They were compared with rats kept on the same diet for 3 or 5 days and on adequate protein for one additional day. The incorporation of 14C‐labelled amino acid into protein was studied in systems containing ATP, GTP, phosphoenolpyruvate, pyruvate kinase and if required, a mixture of unlabelled amino acids and either the 6000 g supernatant fraction of a brain homogenate or microsomes and soluble enzymes. The 6000 g supernatant fraction showed variation in amino acid incorporating activity as well as in RNase activity as measured by breakdown of labelled polyuridylic acid. There was no difference in RNase activity in isolated microsomes, but the amino acid incorporating activity was significantly higher in preparations obtained from rats fed one meal of protein after 5 days of protein‐starvation.