bluuebunny/crossref_metadata_2025 huggingface dataset:
ULTRAVIOLET ABSORPTION CHARACTERISTICS OF MYELIN FROM THE CENTRAL NERVOUS SYSTEM
Authors: Gent W. L. G. , Gregson N. A. , Lovelidge Carol A. , Winder A. F.
Published: October 2006

—New data are presented and published data reviewed to show that the protein content of rat brain myelin must be close to 21 per cent. Ultraviolet absorption measurements in the 220 nm region, however, indicate an apparent protein content of 44·3 per cent which, after solubilization with lysophosphatidylcholine falls to 35·8 per cent. It is shown that this latter proportion can be accounted for in terms of u.v. absorption by myelin protein and lipids, contributions being made by sphingolipids, phospholipids and cholesterol. It is concluded that in the environment of the intact myelin structure, u.v. absorption due to some of the chromophores is enhanced and that this effect is relaxed by lysophosphatidylcholine solubilization. Supportive evidence is given from measurements in the 280 nm region.
THE DISTRIBUTION OF LIPIDS IN THE HUMAN NERVOUS SYSTEM‐V. GANGLIOSIDES AND ALLIED NEUTRAL GLYCOLIPIDS OF INFANT BRAIN
Authors: Vanier M. T. , Holm M. , Månsson J. E. , Svennerholm L.
Published: October 2006

—Gangliosides and allied neutral glycosylceramides were isolated from human infant (2‐24 months of age) cerebral cortex and white matter. The individual glycolipids were separated quantitatively by a combination of column and thin‐layer chromatographic methods on silica gel, DEAE‐cellulose and Sephadex G‐25. In cerebral cortex GD1a and GM1 were the major fractions and constituted more than 70 per cent of the total gangliosides. The concentrations of neutral glycolipids, except for galactosylceramides, were very low: lactosylceramide and glucosylceramide comprised 30 and 5 nmol/g wet weight, respectively. In white matter their concentrations were 10 times higher. The ganglioside concentration was only 50 per cent of that in cerebral cortex: the difference was accounted for mainly by the much lower content of the major di‐ and trisialogangliosides.

Stearic acid was the predominant fatty acid of all brain gangliosides. GM3, and GD3 had a considerable content of the very long‐chain fatty acids, C22‐C24, particularly in the white matter. Glucosylceramide and lactosylceramide had almost identical fatty acid patterns between each other in cerebral cortex and white matter. In the cerebral cortex stearic acid and in the white matter the very long‐chain acids predominated. d20:1 Sphingosine comprised more than 20 per cent of total sphingosine in all the gangliosides of the Gl‐ and G2‐series. GM3, and GD3 like lactosylceramide contained significantly less of d20:1 sphingosine. The findings suggest the existence of separate compartments for the biosynthesis of the gangliosides. Glucosylceramides and lactosylceramides of white matter have the same ceramide composition as the galactosylceramides with normal fatty acids and are thus unlikely to be intermediates in the metabolism of the major brain gangliosides which have a completely different fatty acid composition.
AMINO ACIDS AS CENTRAL NERVOUS TRANSMITTERS: THE INFLUENCE OF IONS, AMINO ACID ANALOGUES, AND ONTOGENY ON TRANSPORT SYSTEMS for l‐GLUTAMIC AND l‐ASPARTIC ACIDS AND GLYCINE INTO CENTRAL NERVOUS SYNAPTOSOMES OF THE RAT1
Authors: Bennett J. P. , Logan W. J. , Snyder S. H.
Published: October 2006

—The accumulation by synaptosomal fractions from rat central nervous system tissue of transmitter candidate amino acids and non‐candidate amino acids was studied with respect to ionic requirements, metabolic inhibitors, structural analogues, and ontogeny. For l‐glutamic and l‐aspartic acids in cortex and spinal cord and glycine in spinal cord a stringent sodium requirement for high affinity uptake was demonstrated. Detailed kinetic analysis of the sodium requirement for glutamic acid uptake into cortical synaptosomal fractions suggests that: (1) sodium ion acts both competitively and non‐competitively in determining the velocity of high affinity uptake; (2) in the absence of sodium ion only the low affinity uptake can be demonstrated; and (3) inhibition of the Na–K‐ATPase enzyme system with ouabain reduces the velocity of uptake to 60% of control values in contrast to alanine whose synaptosomal uptake is less dependent on this enzyme system. No potent inhibitors of l‐glutamic acid accumulation were found among several structural analogues or derivatives. The kinetic analysis for glycine accumulation was more complex and suggested allosteric interactions between glycine and sodium ion. Developmental studies revealed GABA and l‐glutamic acid to have absolute sodium requirements for cortical synaptosomal accumulation from the 16th gestational day through adulthood, with glycine accumulation showing a decreasing sodium requirement as maturation proceeded over this period. The combined evidence suggests that sodium requirement for high affinity uptake is a characteristic of neuroactive substances and may be used as a screening tool to search for other neurotransmitter candidates.
CHANGES IN CEREBRAL CORTICAL LIPIDS IN COBALT‐INDUCED EPILEPSY
Authors: Cenedella R. J. , Craig C. R.
Published: October 2006

Abstract– In control rats and in rats rendered epileptic by insertion of cobalt slivers into the cerebral cortex, total free fatty acids, free cholesterol, esterified cholesterol, triglycerides and phospholipids were measured in normal and lesion areas of cerebral cortex. The cortical lipid profile of the adult rat resembled that of the whole brain of very young rats rather than that of adult whole brain, with the principal differences from whole adult brain being lower total lipid content, increased proportions of phosphatidyl choline in the phospholipid fraction, and higher levels of cholesterol esters. Cobalt‐induced epilepsy was associated with significant changes in cerebral cortical lipids in the area of the lesion and in the non‐necrotic tissue adjacent to the lesion. The total lipid in the area of the lesion decreased sharply as a result of reductions in free cholesterol and total phospholipids. The levels of cholesterol esters and triglycerides increased in the area of the lesion, and cholesterol esters were also increased in the adjacent tissue. In addition there were decreases in the proportion of phosphatidyl ethanolamine in the phospholipids from the lesion site and adjacent tissue and decreases in the proportions of oleic, arachidonic and nervonic acids (unsaturated acids), and an increase in the proportions of lignoceric acid in the phospholipids. In the site of the lesion only, we observed a decrease in phospholipid palmitic acid and an appreciable increase in the proportions of an unidentified long‐chained fatty acid.
GLYCERIDE METABOLISM IN CULTURED CELLS DISSOCIATED FROM RAT CEREBRAL CORTEX1
Authors: Yavin E. , Menkes J. H.
Published: October 2006

Abstract— [1‐14C]stearic acid and [2‐3H]glycerol were rapidly taken up and esterified into triacylglycerol and phospholipids by rat brain cells cultivated in monolayers. Expressed in terms of pool size, the incorporation of glycerol and stearate into triacylglycerol was 6‐ and 8‐fold, respectively, higher than the incorporation into the choline phosphoglycerides. Tritium‐labelled glycerol in both triacylglycerol and glycerophosphatides was diluted more rapidly than the [14C] labelled fatty acids. Chase experiments indicated a transfer of fatty acid from one lipid class to another, mainly from triacylglycerol to phospholipids, with no apparent loss of radioactivity. The accumulation of triacylglycerol in the brain cells was a function of both the presence of exogenous fatty acids in the culture medium and the metabolic needs of the cells; as long as the cells were involved in active formation of membranes the proportion of triacylglycerol was relatively small; its concentration increased while cell division slowed down in older, fully monolayered cultures.
STUDIES OF MONOAMINE OXIDASES1: PROPERTIES OF THE ENZYME IN BOVINE AND RABBIT BRAIN MITOCHONDRIA
Authors: Achee F. M. , Togulga G. , Gabay S.
Published: October 2006

Brain mitochondria were prepared from rabbit and bovine cerebral cortex and the purity and intactness of the preparation assessed through the use of enzyme markers and electron microscopy. Enzymatic properties of monoamine oxidase were studied in the purified mitochondrial preparations which were essentially devoid of major contamination by other organelles, especially microsomes. Five substrates were used for characterization of the enzyme: dopamine, kynuramine, serotonin, tryptamine and tyramine. It was found that there was considerable substrate variation in the properties, but in general, the two species showed similar characteristics. The more pertinent findings were: (1) apparent Km values ranged from 1.1 ± 10−5m for tryptamine to 2.5 ± 10−4m for dopamine; (2) substrate specificity from Vmax values in decreasing order was tyramine > dopamine > kynuramine > serotonin > tryptamine for the bovine enzyme and tyramine > kynuramine > dopamine > serotonin > tryptamine for rabbit; (3) there appeared to be three distinct pH optima according to substrate: pH 7.5 for phenylethylamines, pH 8.2–8.5 for the indolylamines and pH 9.1 for kynuramine; and (4) the activity with tyramine was highly sensitive to increased oxygen tension while kynuramine showed no sensitivity. It is proposed that the properties of monoamine oxidase, a membrane‐bound enzyme, might be influenced by the microenvironment and results are also discussed in terms of multiple forms or multiple activity sites on a single form.
FORMAMIDASE IN RAT BRAIN
Authors: Tsuda H. , Noguchi T. , Kido R.
Published: October 2006

Kynurenine formamidase (aryl‐formylamine amidohydrolase, EC 3.5.1.9) was found to be present in rat brain and was partially purified and characterized. The partially purified enzyme catalysed the hydrolysis of 5‐hydroxyformyl‐dl‐kynurenine to 5‐hydroxy‐dl‐kynurenine and that of formyl‐l‐kynurenine to l‐kynurenine at similar rates. The apparent Km values of the enzyme for 5‐hydroxyformyl‐dl‐kynurenine and formyl‐l‐kynurenine were 4.0 ± 10−4 and 1.8 ± 10−4m, respectively. The enzyme was active over a wide pH range (5.5–8.5). The activity was inhibited by low concentrations of Ag+ and Hg2+. The physiological significance of the enzyme is discussed.
EFFECTS OF LIDOCAINE ON RABBIT BRAIN MICROTUBULAR PROTEIN1
Authors: Haschke R. H. , Byers Margaret R. , Fink B. Raymond
Published: October 2006

Microtubule repolymerization from a crude supernatant fraction prepared from rabbit brain was followed quantitatively by viscometry and electron microscopy. Lidocaine inhibits this repolymerization in a dose‐dependent fashion and the effect is completely reversible upon removal of the lidocaine by dialysis. Direct counting of microtubules by electron microscopy indicates that the local anesthetic decreases the number of tubules without significantly affecting their length. An association constant of lidocaine for tubulin is estimated at 7.5 mm. Procaine and etidocaine were also found to affect the polymerization of microtubules with results similar to those found with lidocaine.
QUANTITATIVE LYSOSOMAL ENZYME ACTIVITY CHANGES IN THE NEURAL LOBE OF THE RAT FOLLOWING WATER DEPRIVATION AND LACTATION
Authors: Bohr G. J. , Jongkind J. F.
Published: October 2006

—The activities of five lysosomal enzymes, acid phosphatase, β‐glucosidase, β‐glucuronidase, β‐galactosidase and N‐arylamidase (classified according to Marks (1970)) were measured by means of sensitive microchemical techniques in frozen‐dried rat neural lobe tissue after experimental and physiological stimulation of hormone release from the hypothalamo–neurohypophysial system i.e. water deprivation (3 and 6 days), delivery and lactation (10 days). During all conditions of stimulation increases of 29 to 106 per cent were measured for lysosomal enzyme activity, expressed as mmol/ng DNA/h. With histochemical staining methods the acid phosphatase activity appears to be mainly localized in the pituicytes, but it was impossible to visualize the microchemically measured acid phosphatase activity increase within the two main compartments of the neurohypophysis, i.e. axonal endings and the neurohypophysial glial cells, the pituicytes.
STEROL CONTENT AND SQUALENE‐2(3)‐EPOXIDE‐LANOSTEROL CYCLASE ACTIVITY IN HUMAN FOETAL BRAIN DURING EARLY AND MID‐GESTATION1
Authors: Dennick R. G. , Worthington K. J. , Abramovich D. R. , Dean P. D. G.
Published: October 2006

—Cholesterol, desmostcrol and squalene‐2(3)‐epoxide‐lanostcrol cyclase were assayed in various regions of human foetal brain from 10 to 22 weeks gestation. The cerebellum, thalamus and hypothalamus, and the ‘remainder’ of the brain were analysed. The proportion of desmosterol to cholesterol was highest in the thalamus and hypothalamus and lowest in the cerebellum. It is suggested that the ratio of desmosterol to cholesterol gives an indication of the state of maturity of a given region, particularly with respect to myelination. Thus the higher levels of desmosterol detected in the thalamus and hypothalamus may be correlated with earlier myelination in this region compared to the cerebellum which myelinates much later in development.

Squalene‐2(3)‐epoxide‐lanosterol cyclase activity in whole brain showed three phases during the period studied; an initial low level up to 15 weeks, a slight increase in activity from 15 to 18 weeks (corresponding to neuroblast multiplication) and a sharp increase after 18 weeks (corresponding to glial multiplication prior to myelination). The enzyme was shown to be microsomal although freezing and thawing of whole brain tended to result in its solubilization. The apparent Km was found to be 2.5 × 10−6m and the effects of the inhibitors iminosqualene and di‐iminosqualene were studied. A comparison was made between the brain enzyme and the liver enzyme at the same age and it was seen that at 22 weeks there was a large increase in activity in the brain, prior to myelination, which was not paralleled by an increase in the activity of the liver enzyme. In this study we have measured the levels of cholesterol, desmosterol and squa‐lene‐2(3)‐epoxide‐lanosterol cyclase in whole human foctal brain, thalamus and hypothalamus, and cerebellum during early and mid‐gestation. We have also examined various properties of the cyclase enzyme and in particular the variations in its activity during early brain development.
CEREBROSIDE MAY BE FALSELY IDENTIFIED AS A SOLUBLE ‘BRAIN SPECIFIC PROTEIN’
Authors: Tremblay J. , Simon M. , Barondes S. H.
Published: October 2006

—Injection of a soluble protein fraction from mouse brain into rabbits gave rise to an antibody which was specific for galactocerebroside. The antigen had the following characteristics: (1) it was present in the soluble fraction of a mouse brain homogenate but absent from the soluble fraction of homogenates of mouse liver, spleen, kidney and testis; (2) it was non‐dialysable; (3) it voided from a Sephadex G200 column; (4) on immunodiffusion with antibody directed against it, it gave a sharp single precipitin band; (5) it bound to DEAE cellulose column and was eluted with high salt. Given these characteristics the antigen might have been identified as a ‘brain specific protein’. However, the lipid nature of the antigen was revealed when it was found that it was not destroyed by Pronase digestion and could be quantitatively extracted with chloroform‐methanol. The antigen has been identified as a galaetocerebroside and is 100 times more abundant in the myelin fraction than in the soluble fraction of the mouse brain homogenates. The antigen could have been falsely identified as a ‘brain specific protein’ if the antigenicity and macromolecular behaviour of lipids was overlooked.
DEVELOPMENT OF AN EXPRESSION WHICH RELATES THE EXCITABLE STATE OF THE BRAIN TO THE LEVEL OF GAD ACTIVITY AND GABA CONTENT, WITH PARTICULAR REFERENCE TO THE ACTION OF HYDRAZINE AND ITS DERIVATIVES
Authors: Wood J. D. , Peesker S. J.
Published: October 2006

—The effect of hydrazine, unsymmetrical dimethylhydrazine (UDMH) and symmetrical dimethyl hydrazine (SDMH) on GABA metabolism in mouse brain was studied. All three compounds inhibited the activity of glutamic acid decarboxylase, although to different extents. In contrast, very different effects were observed on GABA levels; UDMH causing a decrease, SDMH no effect, and hydrazine a marked increase in the content of the amino acid. These results together with previous data obtained by the authors were used to develop an equation which related the excitable state of the brain to changes in overall GABA metabolism. The major factor affecting brain excitability was a change in the activity of glutamic acid decarboxylase, with a change in the concentration of GABA playing a more minor role. It was suggested that the values obtained from the equation might reflect the content of GABA in a critical subcellular location such as the synaptic cleft.
EFFECT OF NEUROTROPIC AGENTS ON TOTAL PYRIDOXAL PHOSPHATE AND ON THE ACTIVITY OF THE DECARBOXYLASE OF AROMATIC AMINO ACIDS AS WELL AS OF OTHER PYRIDOXAL PHOSPHATE‐DEPENDENT ENZYMES IN RAT BRAIN1
Authors: Gey K. F. , Georgi H.
Published: October 2006

—(1) Rats received single intraperitoneal injections of various neuroactive chemicals in order to compare the changes of gross behaviour and the level of pyridoxal phosphate as well as the activity of the decarboxylase of aromatic amino acids, of glutamate decarboxylase and of tyrosine transaminase in the brain.

(2) The majority of excitatory agents tested (i.e. convulsives like amino‐oxyacetate, thiosemicarbazide, pentylenetetrazol and oxotremorine; stimulants such as amphetamine, theophylline and methylphenidate; the amphetamine‐like monoamine oxidase inhibitor tranylcypromine as well as the classical monoamine oxidase inhibitor iproniazid when combined with the monoamine releaser Ro 4‐1284) caused a decrease in aromatic decarboxylase activity which was coexistent with maximal changes of gross behaviour and partly preceded the latter. The level of pyridoxal phosphate was only partially parallel. As an exception, depression of aromatic decarboxylase was lacking after cocaine (which reduced pyridoxal phosphate only), atropine, the hallucinogens lysergic acid diethylamide and mescaline as well as the combination of the dopamine precursor l‐DOPA and the aromatic decarboxylase inhibitor Ro 4‐4602.

(3) Depression of obvious central nervous functions was almost regularly accompanied and in part preceded by increase of DCA activity (i.e. with the anaesthetics pentobarbitone, diethyl ether and chloroform, the neuroleptics chlorpromazine, haloperidol, reserpine and the benzoquinolizine Ro 4‐1284 as well as the tranquillizers diazepam and chlordiazepoxide). Pyridoxal phosphate was increased during or after maximal behavioural changes by pentobarbitone and chlorpromazine only. As an exception, activation of aromatic decarboxylase was absent after morphine.

(4) The activity of glutamate decarboxylase was significantly reduced by thiosemicarbazide only, whereas a distinct increase in enzyme activity was exclusively observed after atropine.

(5) Tyrosine transaminase activity was significantly diminished by amino‐oxyacetate only and showed a late increase after tranylcypromine.

(6) It is concluded that there is an inverse relationship, in the majority of neuroactive chemicals tested, between changes of gross behaviour and cerebral aromatic decarboxylase activity. Thereby, the latter is neither regularly related to corresponding variations of the total cerebral pyridoxal phosphate nor to hitherto described alterations of the monoamine turnover nor to effects on other vitamin B6‐dependent enzymes.
CHANGES DURING DEVELOPMENT OF MOUSE BRAIN IN THE ACTIVITIES AND SUBCELLULAR DISTRIBUTIONS OF CREATINE AND ADENYLATE KINASES
Authors: Lapin Evelyn P. , Maker H. S. , Lehrer G. M.
Published: October 2006

Abstract— The activities and electrophoretic patterns of creatine (CK) and adenylate (AK) phosphokinases were determined in the mitochondrial and high speed supernatant fractions of developing and adult mouse brain. The CK activity of the cytosol increases three‐fold between 9 and 19 days of age and four‐fold by 29 days. Mitochondrial CK activity increases from birth to reach a maximum four‐fold that at birth by 19 days of age. The developmental changes in soluble AK activity parallels that of CK. Although the increase in CK activity of the mitochondria exceeds that of the mitochondrial proteins during the period of rapid brain development, mitochondrial AK specific activity changes little. No major changes were found during development in the electrophoretic patterns of proteins with CK or AK activity in the supernatant and mitochondrial fractions. The changes in mitochondrial CK and AK activity parallel the change from a predominantly glycolytic to an aerobic mode of brain metabolism and support the concept that these enzymes play an important role in mitochondrial energy metabolism. Soluble CK and AK activity increase concomitant with neuronal maturation and the associated greatly increased need for rapidly available high energy phosphate.
FLOW IN VIVO OF GLUCOSE CARBON TO BRAIN PROTEIN IN RATS: EFFECT OF STARVATION
Authors: Barkai A. , Mahadik S. , Rapport M. M.
Published: October 2006

—The conversion of plasma glucose into brain proteins in vivo was measured in rats after various periods of food deprivation. Rates of flow of glucose carbon into both soluble and insoluble brain proteins were calculated from the curve representing the decrease of plasma [14C]‐glucose specific activity with time, and from the specific activity of brain protein 180 min after intravenous injection of a tracer dose of d‐[14C]‐glucose. Compared to the post‐absorptive rats, food deprivation for 72 h caused a 30 per cent reduction in the rate of flow of glucose carbon into soluble brain proteins but did not affect the flow into insoluble proteins. Results of experiments in which the soluble brain proteins were separated by isoelectric focusing suggest that prolonged fasting in adult rats causes substantial differences in the conversion of glucose to different proteins.
NUCLEAR PROTEINS OF THE GUINEA PIG BRAIN
Authors: Uyemura K. , Nakayama T. , Kitamura K. , Yamanaka T. , Hirano S.
Published: October 2006

Abstract—

Chromatin protein fractions were separated from the nuclei from brain, liver and kidney of the guinea pig. The fractions were studied by electrophoretic methods and amino acid analysis.

Brain nuclear fractions were washed with 0.15m‐NaCl and nuclear acidic proteins then removed by 0.35 m‐NaCl. These 0.35 m‐NaCl‐extracted proteins were considered to be similar to the nuclear soluble acidic proteins.

Nonhistone‐1, histone and nonhistone‐2 fractions were obtained from 2.0 m‐NaCl‐soluble chromatin fractions by lowering the salt concentration and successive extraction with acid and alkali. The nonhistone‐3 fraction was also extracted from the nuclear residue by alkaline solution.

The contents and characteristics of the nonhistone fractions of the brain, especially the nonhistone‐1 fraction, differed among the three tissues. The histone fractions showed no obvious difference among the three tissues. The nonhistone‐1 fraction of the brain, which comprised a low percentage of total nuclear protein, contained relatively high amounts of acidic proteins.
EFFECTS OF PRE‐WEANING AND POST‐WEANING UNDERNUTRITION ON ACETYLCHOLINE LEVELS IN RAT BRAIN
Authors: Rajalakshmi R. , Kulkarni A. B. , Ramakrishnan C. V.
Published: October 2006

Abstract— Studies were made of the effects of undernutrition during the neonatal period and also protein deficiency and undernutrition during the post‐weaning period on brain acetylcholine. Rats undernourished from birth to 4 weeks so as to result in a body wt deficit of 43 per cent had an associated deficit in brain wt of 14 per cent, but the concentration of acetylcholine in the brain was not affected. In the case of post‐weaning undernutrition, acetylcholine concn was found to be affected in protein deficiency as well as in severe calorie restriction.
TURNOVER OF PROTEIN PHOSPHORUS IN RESPIRING SLICES OF GUINEA PIG CEREBRAL CORTEX: CELLULAR LOCALIZATION OF PHOSPHOPROTEIN SENSITIVE TO ELECTRICAL STIMULATION
Authors: Williams M. , Pavlik A. , Rodnight R.
Published: October 2006

Abstract— In experiments designed to localize the increased turnover of phosphoprotein‐P which occurs in respiring brain slices as a result of electrical stimulation, a cell separation procedure was used to prepare a fraction enriched in neuronal cell bodies from incubated slices labelled with [32P]phosphate. Labelled phosphoprotein was found to be twice as concentrated in the neuron‐enriched fraction as in other fractions. Electrical stimulation for 10 s increased the rate of incorporation of [32P]phosphate into phosphoproteins in the neuron‐enriched fraction by 25 per cent (P < 0.05), but had no effect on incorporation into a partially purified glial fraction contaminated with neuropil and cell debris.
THE EXTENT OF AXOPLASMIC TRANSPORT DURING DEVELOPMENT, DETERMINED BY MIGRATION OF VARIOUS RADIOACTIVELY‐LABELLED MATERIALS
Authors: Bondy S. C. , Madsen Carol Jean
Published: October 2006

Abstract— Several isotopic precursors have been monocularly injected into chick embryos and into day‐old or 15‐day‐old chicks. After various intervals, the incorporation of various isotopes into acid insoluble material within the retina of the injected eye and within the optic lobes, was determined. Radioactive proline and fucose were used as precursors of protein and glycoprotein respectively while uridine was used as an RNA precursor. The proportion of rapidly migrating proteins and glycoproteins was reduced during maturation. The extent of RNA migrating also appeared to decline during development. The proportion of synthesized protein that was transported was relatively constant and independent of the amino acid used. Around 30 per cent of retinally synthesized glycoprotein migrated distally and this migrating material appeared to contain very few sialic acid residues. A considerable amount of retinally synthesized gangliosides also appeared rapidly in the distal regions of the optic nerve.
EVIDENCE FOR SPECIFIC SYNAPTOSOMAL LOCALIZATION OF EXOGENOUS ACCUMULATED TAURINE1
Authors: Sieghart W. , Karobath M.
Published: October 2006

Abstract— Equilibrium or incomplete equilibrium density gradient centrifugation was used to characterize the subcellular localization of exogenous [3 5S]taurine which was taken up by minces or homogenates of rat cerebral cortex. [3 5S]Taurine is accumulated in synaptosomes, which sediment more slowly than l‐[3H]norepinephrine‐accumulating particles. When [3 5S]taurine and [3H]GABA are accumulated by minces, a small difference in the sedimentation profile of taurine and GABA was observed, but no difference was found when taurine and intrasynaptosomal potassium were compared. However, potassium sedimented more slowly after incubation of homogenates than of minces. These data give evidence for the accumulation of [3 5S]taurine by a specific synaptosomal population.
CHANGES IN THE SCIATIC NERVE OF THE RABBIT AND ITS TISSUE CONSTITUENTS DURING DEVELOPMENT1
Authors: Yates A. J. , Wherrett J. R.
Published: October 2006

Abstract— A segment, defined by gross anatomic boundaries, which comprises most of the sciatic nerve was dissected from rabbits aged from birth to 1 yr. The mean and standard deviation of the variance determined for the weights of pairs of nerve units removed from single animals of an age group did not exceed 2·7 per cent and 12·3 per cent respectively of the average weight of the two nerve units which were the values determined for a group of newborn animals. During the period from birth to one year of age, the weight and length of the nerve unit increased 47‐ and 6‐fold respectively while the animal's weight increased 78‐fold. Whereas the nerve unit length increased little after 8 weeks, its weight and that of the whole animal continued to increase up to 1 year. Estimations of nucleic acids in the nerve unit from adult animals gave values of 54 μg DNA‐P and 25 μg RNA‐P per g fresh weight. During the period birth to 1 yr the absolute amount of DNA in the nerve unit increased 11‐fold, 71 per cent of this having occurred by 6 weeks of age. The absolute amount of RNA increased 11 ‐fold by 8 weeks of age and remained constant thereafter. During the period birth to 1 yr, the proportion of the nerve constituents accounted for by lipid‐free solids remained constant at 10 per cent, while lipids increased from 5 to 18 per cent and tissue water declined from 84 to 71 per cent. Changes in some lipid classes were examined also. Increases of absolute content in the nerve unit over the first year and concentrations on a fresh weight basis attained in year‐old animals were as follows: cholesterol, 132‐fold and 86 mg/g; triglyceride 554‐fold and 43·2 mg/g; total phospholipid, 85‐fold and 61 mg/g; cerebroside 205‐fold and 28 μmol/g; sulphatide, 154‐fold and 10 μmol/g; monogalactosyl diglyceride, 31‐fold and 0·6 μmol/g. The ratio cholesterol/phospholipid/galactolipid in whole nerve units from adult animals was 2·0/2·1/1·0 and the change in this ratio in the first year was compatible with enrichment of myelin in galactolipid during myelination. The ratio of cerebroside to sulphatide increased from 2·0 to 2·6 during this period. Increases in absolute content and concentrations attained for sialic acid‐containing components representing cell surface constituents were as follows: ganglioside sialic acid, 33‐fold, and 83 μg/g; glycoprotein sialic acid, 57‐fold and 371 μg/g. The quantitative pattern of ganglioside fractions separated by thin‐layer chromatography in one direction resembled that of whole brain and was the same at all ages studied. The changes reported reflect a composite picture of changes in a variety of cell membranes indicative of marked variation during development in quantity and composition of membranes.
THE P2 PROTEIN OF BOVINE ROOT MYELIN: ISOLATION AND SOME CHEMICAL AND IMMUNOLOGICAL PROPERTIES1
Authors: Brostoff S. W. , Sacks H. , Canto M. Dal , Johnson A. B. , Raine C. S. , Wisniewski H.
Published: October 2006

Abstract— A small basic protein (mol.wt. 12,000), referred to as the P2 protein, was extracted with dilute acid from delipidated bovine root myelin and purified by ion exchange chromatography on cellulose phosphate. It appeared homogeneous on polyacrylamide gel electrophoresis. The P2 protein had a distinctly different amino acid composition than the larger basic protein (mol.wt. 18,000), referred to as the P1 protein, that is also present in peripheral nerve myelin. It contained relatively more hydrophobic residues and much less histidine and proline. The P2 protein conjugated with peroxidase was bound by lymph node cells and infiltrates in rabbits sensitized with whole bovine root myelin. No binding was evident with the bovine central nervous system myelin basic protein. Chemically and immunologically, the P2 protein appears to be specific to peripheral nervous system myelin. The isolated P2 protein produced mild clinical symptoms of experimental allergic neuritis, but no histological evidence of disease. It was suggested that the P2 protein is an important antigen for experimental allergic neuritis, and that its antigenic determinants are likely to be conformation‐dependent.
INCORPORATION OF 32P INTO THE PHOSPHOLIPIDS OF NEURONAL AND GLIAL CELL ENRICHED FRACTIONS ISOLATED FROM RABBIT CEREBRAL CORTEX: EFFECT OF NOREPINEPHRINE
Authors: Woelk H. , Kanig K. , Peiler‐Ichikawa K.
Published: October 2006

Abstract— Glial cells isolated from rabbit cerebral cortex contained approximately one‐third more phospholipids per unit protein than the neuronal cell bodies. The pattern of individual phospholipids was rather similar in both cell types. The incorporation of intracisternally administered 32P into neuronal and glial phospholipid classes of rabbit brain was studied at intervals ranging from 5 to 60min. In general, for all investigated phospholipids the incorporation of the label was somewhat faster in neurons than in glial cells. Phosphatidylinositol showed the fastest and ethanolamine plasmalogen the slowest incorporation of 32P in both neurons and glial cells. A lag phase of about 10 min could be observed before labelling of the glial phosphatidylcholine, phosphatidylethanolamine, ethanolamine plasmalogen, phosphatidylserine and sphingomyelin had occurred. Among the neuronal phospholipids a lag phase was found only for the labelling of the ethanolamine plasmalogen. Norepinephrine increased the incoropration of 32P into phosphatidylinositol of both glia and neurons but had no effect on the specific radioactivity of ethanolamine plasmalogen and sphingomyelin. Labelling of phosphatidylcholine was slightly inhibited in both cell types by the administration of norepinephrine.
EFFECT OF THYROID DEFICIENCY ON THE LEVELS OF SEVERAL ENZYMES IN RAT BRAIN
Authors: Bera H. , Chatterjee G. C.
Published: October 2006

—Activities of acid phosphatase, alkaline phosphatase and β‐glucuronidase have been estimated in the brain tissues, using various subcellular particles, in growing thyroidectomized rats and also using cytoplasmic extracts free from debris and nuclear fraction in young hypothyroid animals. Hepatic glucose‐6‐phosphate dehydrogenase activity was markedly reduced after thyroidectomy but the enzyme was brought back to normal levels by thyroxine treatment. There was no change, however, in the activity of neural glucose‐6‐phosphate dehydrogenase after thyroidectomy. In the thyroidectomized animals an increase only in the free acid phosphatase activity in the neural synaptosomes was found and this increase in activity was not counteracted by administration of thyroxine. In the hypothyroid young animal β‐glucuronidase, acid phosphatase and alkaline phosphatase activities were found to be affected during development.
EFFECTS OF NEONATAL PANTOTHENIC ACID DEFICIENCY ON BRAIN LIPID COMPOSITION IN RATS1
Authors: Rajalakshmi R. , Nakhasi H. L.
Published: October 2006

—Studies were made of the effects of pantothenic acid deficiency during the neonatal period on brain lipids in rats. Mothers with 6–8 pups to a litter were fed from soon after birth a diet either normal or deficient in pantothenate. An additional control group (restricted controls) was pair‐fed with the deficient group. Significant deficits were found in the pups of the pantothenate‐deficient group and in those of the restricted controls with regard to body weight, brain weight and brain concentration of lipids (total lipid, cholesterol, phospholipid, galactolipid and gangliosides) at 21 days of age. The deficits in both these groups were comparable. The results suggest that the effects of pantothenate deficiency may be due to the resulting growth deficit rather than to the deficiency of pantothenate per se.
THE CONVULSANT ACTION OF METHYLDITHIOCARBAZINATE: A COMPARISON WITH OTHER SULPHUR‐CONTAINING HYDRAZIDES
Authors: Meldrum B. S. , Horton R. W. , Sawaya M. C. B.
Published: October 2006

—The convulsant action of methyldithiocarbazinate (MDTC), thiocarbohydrazide (TCH) and thiosemicarbazide (TSC) has been studied in mice. The relationship between dose and time to convulsions indicated that MDTC has a dual action and is more potent than TSC. Pretreatment of mice with pyridoxal phosphate (0.25 mmol/kg) protected against convulsions and death produced by low doses of MDTC or TCH, and low or high doses of TSC. Pretreatment with pyridoxine hydrochloride (0.25 mmol/kg) protected mice against TSC but not against TCH. It protected against low doses of MDTC (0.12 mmol/kg), but shortened the latency to convulsions after intermediate doses of MDTC (0.37 mmol/kg).

Glutamate decarboxylase activity (GAD, EC 4.1.1.15) in whole brain homogenates from mice killed at the onset of seizures, was significantly reduced by all 3 drugs at all doses. This inhibition did not exceed 30% after any dose of TSC or TCH, but was 64% in mice killed 4 min after the injection of MDTC (0.98 mmol/kg). The addition of pyridoxal phosphate to brain homogenates abolished GAD inhibition after MDTC but not after TCH. In vitro brain GAD was 50% inhibited by 10−4m‐MDTC, 18% by 10−4m‐TSC and 8% by 10 −4m‐TCH. Kinetic studies suggested that at low concentrations MDTC inhibits by competing with pyridoxal phosphate. At the onset of convulsions the cerebral content of pyridoxal phosphate was reduced after low or high doses of TSC (0.27 and 2.2 mmol/kg) and after high doses of MDTC (0.98 mmol/kg). All three drugs (at 10−5−10−4m) inhibited pyridoxal phosphokinase (EC 2.7.1.35) in vitro. Short latency convulsions after MDTC (0.37–0.98 mmol/kg) very probably arise from inhibition of cerebral GAD, due to competition for coenzymic sites and/or unavailability of coenzyme. Long‐latency convulsions after MDTC (0.12–0.37 mmol/kg) are comparable to those seen after TSC (0.27–2.2 mmol/kg) and may depend on a mechanism additional to inhibition of GAD.
EARLY EVENTS IN THE EFFECT OF HYDROCORTISONE ACETATE ON DNA REPLICATION IN THE RAT BRAIN
Authors: Burdman J. A. , Jahn G. A. , Szijan I.
Published: October 2006

—Between the injection of hydrocortisone acetate to young rats and the onset of inhibition of DNA synthesis in brain, there is a lag period of 90 min. During these 90 min the only major alteration observed is a reduced formation of the DNA associated proteins while the synthesis of other brain proteins as well as that of RNA is normal. The specific activity of the enzymes thymidine kinase and DNA polymerase is also within control values.

At later times, there is an inhibition in the synthesis of all brain proteins measured and of RNA and in the specific activity of the thymidine kinase. The specific activity of DNA polymerase remains normal throughout the period studied.

These results indicate an important role for the DNA associated proteins in the regulation of DNA replication in rat brain.
PLASMA CHOLINE: ITS TURNOVER AND EXCHANGE WITH BRAIN CHOLINE1
Authors: Freeman J. J. , Choi R. L. , Jenden D. J.
Published: October 2006

—The kinetics of plasma choline (Ch) and the uptake of plasma Ch into the brain were studied by means of intravenous infusion of [2H4]Ch at various rates into anaesthetized and conscious rats. [2H4]Ch levels in both arterial and venous plasma at steady state were linearly related to the infusion rate; however, unlabelled Ch levels were independent of infusion rate. [2H4]Ch levels were higher in the arterial plasma than in the venous plasma, while unlabelled Ch levels were higher in the venous plasma than in the arterial plasma. It was concluded that Ch is being generated in the brain and is released into the venous effluent. The supply of Ch to the plasma is not decreased if the plasma Ch level is increased. The clearance and turnover of Ch in the compartment of its initial distribution are 75 ml kg‐1 min‐1 and 716 nmol kg‐1 min‐1, respectively. The uptake of plasma Ch into the brain is not saturated even at very high levels of plasma Ch.
PROPERTIES OF THIAMINE DI‐ AND TRIPHOSPHATASES IN RAT BRAIN MICROSOMES: EFFECTS OF CHLORPROMAZINE
Authors: Iwata H. , Baba A. , Matsuda T. , Terashita Z.
Published: October 2006

Abstract— The mechanism of the action of chlorpromazine on rat brain thiamine phosphatases were studied to clarify the properties of these enzymes in the CNS. Chlorpromazine at concentrations of 0.25‐1.0 mm caused marked decrease of microsomal and soluble thiamine triphosphatase (TTPase) activities and marked increase of microsomal thiamine diphosphatase (TDPase) activity. Imipramine and desipramine also inhibited TTPase but did not cause any marked change in TDPase activities. Addition of chlorpromazine (0.5 mm) decreased the Vmax of microsomal TTPase by about one‐half, increased that of TDPase about 3‐fold, and lowered the Km value for TDP but not for TTP.

Acetone treatment of the microsomal fraction lowered the TTPase activity and markedly enhanced the TDPase activity. In acetone‐treated microsomes, chlorpromazine also inhibited TTPase activity but did not activate TDPase. Deoxycholate had similar effects to chlorpromazine on these enzyme activities.
IN VITRO STUDIES OF CEREBRAL CORTICAL RNA AND NUCLEOTIDE METABOLISM IN HYPOTHYROIDISM1
Authors: Geel S. E. , Gonzales L. K.
Published: October 2006

—Thyroid hormone deficiency induced during the neonatal period in the rat, resulted in an enhanced incorporation of [2‐14C]uridine and [8‐14C]adenosine in vitro into cerebral cortical RNA at 25 days of age. An examination of the acid‐soluble pool constituents separated by polyethyleneiminecellulose TLC, revealed that all phosphorylated derivatives were more highly labelled compared to controls. These differences were not apparent at a lower incubation temperature (4°C). When the average specific activity of precursor pool ATP labelled from adenosine was utilized for the calculation of the rate of RNA synthesis, no change was observed in hypothyroidism. The results are compatible with a maturational‐dependent increase in nucleoside transport and rate of phosphorylation in hypothyroidism which is reflected in the stimulated incorporation into cerebral RNA. The apparent normal rate of RNA synthesis coupled with a diminished cellular RNA concentration in thyroid hormone deficiency, suggests an increased RNA turnover. Experiments with actinomycin D revealed no apparent difference in the rate of decay of rapidly‐labelled (nuclear) RNA. The possibility is discussed that the processing of nuclear RNA, the formation of stable ribosomal complexes and events at the translational level are subject to modification in developing hypothyroid rats.
BULK ISOLATION OF LARGE VENTRAL SPINAL NEURONS
Authors: Capps‐Covey Patsy , McIlwain D. L.
Published: October 2006

—Cell bodies of spinal neurons can be isolated in bulk fractions, using methods developed for neurons from brain. The technique described here includes sieving steps which allow one to purify and concentrate selectively the larger neuronal perikarya (50 μm or more), most of which could be alpha motoneurons. An average of 170,000 large neurons can be obtained from 50 g of trimmed bovine ventral enlargements. Roughly 6% of the total large neurons in the ventral grey matter are recovered, and 85% of the isolated neurons are larger than 50 μm in their smallest dia. Non‐neuronal contaminants, mostly capillary fragments, account for 19% of the total particles in the fraction. Each isolated neuron contains an average of 9690 pg protein and 1353 pg RNA and hydrolyses 2·2 pmol of acetylthiocholine/min. Pretreatment of the spinal tissue with collagenase before cell isolation is also evaluated here.
BIOCHEMICAL CHANGES IN RAT BRAIN ASSOCIATED WITH THE DEVELOPMENT OF THE BLOOD‐BRAIN BARRIER
Authors: Sessa G. , Perez Maria M.
Published: October 2006

—Subcellular fractions from brains of 5, 10, 13, 16, 21, 30 day‐old and adult rats were prepared. Protein content and various enzyme activities were assayed in all fractions and brain homogenates. γ‐Glutamyl transpeptidase activity and 5′‐nucleotidase were very low at 5 days of life but steadily increased, reaching adult concentrations at about 30 days after birth. Alkaline phosphatase, instead slowly decreased with maturation, while monoamine oxidase after an initial decrease, increased rapidly to adult levels.

The relation between the appearance of enzymatic activity in brain and the blood‐brain barrier function is discussed.
REGULATION OF PALMITIC ACID SYNTHESIS IN CULTURED GLIAL CELLS: EFFECTS OF LIPID ON FATTY ACID SYNTHETASE, ACETYL‐CoA CARBOXYLASE, FATTY ACID AND STEROL SYNTHESIS1
Authors: Volpe J. J. , Marasa J. C.
Published: October 2006

Abstract— C6 glial cells in culture were utilized to study the regulation of the important lipogenic enzymes, fatty acid synthetase and acetyl‐CoA carboxylase, and the synthesis of fatty acids and sterols. Regulation of these phenomena by lipid was demonstrated by the following observations. First, removal of serum from the culture medium was accompanied over the next five days by 2–3‐fold increases in the lipogenic enzymatic activities and in 5–15‐fold increases in rates of incorporation of acetate into fatty acids and sterols. Second, cells grown in delipidated serum exhibited approx 2‐fold higher levels of activity of the lipogenic enzymes and 5–10‐fold higher rates of synthesis of fatty acids and sterols than cells grown in normal calf serum. Third, cells grown in serum‐free medium supplemented with concentrations of fatty acid comparable to those present in medium supplemented with serum exhibited activities of fatty acid synthetase comparable to those exhibited by cells grown in the serum‐supplemented medium. The mechanism of these effects on fatty acid synthetase was shown by immunochemical techniques to involve alterations in content rather than in catalytic efficiency of the enzyme. The changes in content of the synthetase were caused by alterations in enzyme synthesis. In view of morphological and biochemical data suggesting that C6 cells are related to differentiating cells with properties of both astrocytes and oligodendroglia, the present data may indicate that regulation of palmitic acid synthesis by fatty acid or a product thereof occurs in brain during development.
ENZYMATIC ACTIVITY IN TUBULIN PREPARATIONS: CYCLIC‐AMP DEPENDENT PROTEIN KINASE ACTIVITY OF BRAIN MICROTUBULE PROTEIN1
Authors: Soifer D.
Published: October 2006

Abstract—

Cyclic‐AMP stimulates phosphorylation of Hf1 and Hf2b histone fractions and of protamine by tubulin preparations. Lyophilization of the tubulin removes the requirement for cyclic‐AMP; the kinase is fully active in the absence of cyclic nucleotide. The casein kinase activity of tubulin is independent of cyclic‐AMP. Only cyclic‐IMP can replace cyclic‐AMP at the low concentrations at which the cyclic‐AMP is effective. 5′‐AMP inhibits basal levels of Hf 1 histone phosphorylation. Several attempts have been made to separate the kinase activity from tubulin. Both tubulin and kinase activity are precipitated by vinblastine. Mg2+ precipitation of tubulin inactivates the kinase; there is no evidence that the precipitation step removes the kinase from tubulin. Tubulin which has been assembled into microtubules, collected by centrifugation and disassembled, retains its kinase activity. Kinase activity and tubulin co‐elute from DEAE‐cellulose. Taken together, these experiments demonstrate that tubulin, prepared by fractionation with ammonium sulfate followed by elution from DEAE Sephadex with 0‐8 M KC1 and concentration by reprecipitation with ammonium sulfate has a closely associated, cyclic‐AMP dependent protein kinase activity, which may be intrinsic to the tubulin peptides themselves.
EFFECT OF METHIONINE AND METHIONINE SULPHOXIMINE ON RAT BRAIN S‐ADENOSYL METHIONINE LEVELS
Authors: Schatz R. A. , Sellinger O. Z.
Published: October 2006

Abstract—

Rat brain SAM levels were markedly increased after methionine administration, whereas the convulsant, L‐methionine‐dl‐sulphoximine (MSO), produced a 35 per cent decrease in whole brain content of S‐adenosyl‐L‐methionine (SAM). When methionine was given in combination with MSO, SAM levels were not decreased. Studies on the regional distribution of SAM revealed only a small variation between regions (from 24 nmol/g in midbrain to 49‐5 nmol/g in striatum). SAM levels were reduced by about 50 per cent in the cerebellum, striatum, cortex and hippocampus 3 and 6 h after MSO. It is proposed that abberant cerebral methylation processes may be involved in the genesis of the MSO seizure.
MORPHINE INDUCED CALCIUM DEPLETION IN DISCRETE REGIONS OF RAT BRAIN1
Authors: Cardenas H. Lee , Ross D. H.
Published: October 2006

Abstract—

The in vivo administration of a single dose of morphine produces a decrease of tissue calcium in the rat brain. This decrease is observed to be linear, dose‐dependent, time‐dependent and to occur to an equal degree in 8 discrete brain regions. This effect of morphine is blocked by naloxone and exhibits a high degree of sterospecificity. The reserpine induced decrease of brain calcium was not antagonized by naloxone. Differentiation of this response using reserpine and naloxone indicates the possibility of calcium pools in the central nervous system.

The results are discussed in terms of a specific effect of opiate drugs and the role of calcium in opiatereceptor interactions.