bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF LEUCINE ON BRAIN SEROTONIN
Authors: Ramanamurthy P. S. V , Srikantia S. G
Published: October 2006

Abstract— The effect of excess leucine in the diet on serotonin metabolism in the brain was investigated in experimental animals. It was found that:

(1) Animals receiving diets containing 3 % and 8 % leucine and those receiving jowar diets had significantly lower levels of serotonin in the brain.

(2) Intraperitoneal administration of the precursor amino acid 5‐HTP increased the serotonin concentration in brain in both control and leucine‐fed animals. However, the serotonin concentration in leucine‐fed animals was significantly lower than that of pairfed controls. Larger amounts of the synthesized serotonin were found to be catabolized in 3 hr in leucine‐fed animals than in control animals.

(3) The in vitro uptake of [14C]5‐HTP by brain slices of animals fed leucine was found to be similar to that of control animals.

(4) The basal concentration of 5‐HIAA in brain was higher in leucine‐fed animals, suggesting a higher rate of catabolism of serotonin.

(5) Administration of nicotinic acid resulted in a further fall of serotonin concentration in the brains of leucine‐fed animals but not in control animals.
FATTY ACIDS OF LECITHIN IN SUBCELLULAR FRACTIONS DURING MATURATION OF BRAIN
Authors: Skrbic T. R , Cumings J. N
Published: October 2006

Abstract— A study has been made of the fatty acyl profiles of lecithin in subcellular fractions of the brain in rat, guinea pig and rabbit. It was found that cerebral lecithins consisted of at least two groups with dissimilar fatty acyl profiles. The group obtained from myelin showed little variation with age of the rats or among two other species examined. The changes in lecithin fatty acyl composition of brain homogenates were in agreement with a progressively greater contribution of myelin lecithins to brain homogenate lecithins with increasing age.
EFFECTS OF EXCESS DIETARY PHENYLALANINE ON COMPOSITION OF CEREBRAL LIPIDS1
Authors: Geison R. L , Waisman H. A
Published: October 2006

Abstract— Concentrations in whole rat brains of lipids (total lipids, phospholipids, galactolipids, cholesterol, plasmalogens) and of proteolipid protein were not altered after feeding for 2 and 6 weeks of diets containing 5 per cent excess l‐phenylalanine. After 2 weeks of diet with 7 per cent excess l‐phenylalanine there was a slight reduction (5–10 per cent) in the concentrations in whole brain of cholesterol and galactolipids. No significant effects were noted in cerebral hemispheres after 3 weeks of diets with 7 per cent excess l‐phenylalanine. In the 5 and 7 per cent supplemented groups of animals, the total amounts of the various lipids were initially reduced to levels which were within 10 per cent of those in diet‐matched controls. The results for rats indicate that after 3 weeks of age only very moderate effects on accumulation of cerebral lipids can be produced by excess dietary l‐phenylalanine fed at the most toxic levels of supplementation, while lower levels of dietary supplementation are without effect. The results suggest further that the more mature brain is resistant to alteration of deposition of myelin lipids by high levels of phenylalanine.
THE EFFECT OF DENERVATION ON INCORPORATION OF 32P AND [3H]GLYCEROL BY THE MUSCLE MEMBRANE
Authors: Bunch W , Kallsen G , Berry J , Edwards C
Published: October 2006

Abstract— The incorporation in vivo of 32P1 was significantly increased in all glycerophosphatide of preparations of denervated muscle membrane in frogs. There was no increase in incorporation of 32P1 into sphingomyelin. Disuse induced by tenotomy did not significantly increase incorporation of 32P1 into phospholipids of the muscle membrane. The phospholipid content of muscle membranes remained unchanged as a result of denervation or tenotomy. Denervation produced an increase in the incorporation of [2‐3H]glycerol into all glycerophosphatides in parallel with the increase in 32P1 incorporation. Although the stimulated incorporation of 32P1 was increased in the regions of the muscle membrane rich in endplates, the most marked effect was in the endplate‐poor region where activity in phosphatidylserine was most markedly increased.
PROTEIN SYNTHESIS IN FRACTIONS FROM ISOLATED BRAIN CELL NUCLEI
Authors: Burdman J. A , Haglid K , Dravid A. R
Published: October 2006

Abstract— 1. The incorporation in vivo and in vitro of isotopically labelled leucine into fractions of nuclear proteins from young and adult rat brain was investigated.

2. During post‐natal cerebral maturation, the ability of nuclei from brain cells to synthesize proteins decreased. The specific activities of all the fractions of nuclear protein were highest in 3‐day‐old rats and declined thereafter. Nuclei from adult brain cells exhibited only 10 per cent of the activity found in nuclei from brain cells of 3‐day‐old rats.

3. The ‘residual protein’ fraction was most rapidly labelled, peak activity being reached within 30 min after injection. In vitro, the ‘residual protein’ fraction attained maximum activity within 40 min.

4. The specific activity of the chromatin acidic proteins (HCl‐insoluble) was considerably higher than that of the histones both in vivo and in vitro. Histones were the most inert of all the nuclear protein fractions studied.

The possible functional significance of the various protein fractions during the process of cerebral maturation and in the adult brain is discussed.
THE NATURE OF SULPHATION OF URONIC ACID‐CONTAINING GLYCOSAMINOGLYCANS CATALYSED BY BRAIN SULPHOTRANSFERASE
Authors: George Elizabeth , Singh Manoranjan , Bachhawat B. K.
Published: October 2006

—A sulphotransferase system of rat brain catalyses the transfer of sulphate from 3′‐phosphoadenosine 5′‐phosphosulphate to the low‐sulphated glycosaminoglycans isolated from normal adult human brain. These were shown to be precursors of higher‐sulphated glycosaminoglycans by DEAE‐Sephadex column chromatography and paper electrophoresis. Nitrous acid degradation and mild acid hydrolysis of enzymically‐sulphated fractions further confirmed the presence of heparan sulphate in human brain.

A partially purified sulphotransferase preparation was obtained from neonatal human brain using chondroitin‐4‐sulphate as sulphate acceptor. This sulphotransferase catalyses the transfer of sulphate to the various uronic acid containing glycosaminoglycans. Heparan sulphate was the best sulphate acceptor followed by dermatan sulphate, N‐desulphoheparin, chondroitin‐4‐sulphate and chondroitin‐6‐sulphate in decreasing order. Sulphotransferase obtained from 1‐day‐old rat, rabbit and guinea pig brain also had the same pattern of specificity towards various sulphate acceptors.

This sulphotransferase catalyses both N‐sulphation and O‐sulphation. Studies on the sulphotransferase obtained from both rat and human brain of various age groups indicate that the ratio of N‐sulphation: O‐sulphation decreases as the brain matures.
CEREBRAL LIPID METABOLISM IN EXPERIMENTAL HYPERPHENYLALANINAEMIA: INCORPORATION OF 14C‐LABELLED GLUCOSE INTO TOTAL LIPIDS*
Authors: Shah S. N. , Peterson N. A. , McKean C. M.
Published: October 2006

—1. Effects of the administration of phenylalanine to rats on incorporation in vivo or in vitro of [U‐14C]glucose into cerebral lipids were studied during the first 5–10 days of postnatal development. In addition, the effects of added phenylalanine and its deaminated metabolites on incorporation of [U‐14C]glucose by homogenates into lipids of developing rat brain were investigated. Hyperphenylalaninaemia reduced incorporation both in vivo and in vitro of [U‐14C]glucose into cerebral lipids.

2. Phenylalanine or tyrosine added in vitro at concentrations equivalent to those in the brain of the hyperphenylalaninaemic rat (0‐1 μmole/ml incubation medium) did not inhibit incorporation of [U‐14C)glucose into lipids, although at much higher concentrations of phenylalanine (36 μumoles/ml incubation medium) slight inhibition (10 per cent) of incorporation of [U‐14C]glucose into lipids was observed.

3. In contrast, the deaminated metabolites in general exerted greater inhibitory effects at lower concentrations. Phenyllactic acid, in comparison to phenylpyruvic and phenyl‐acetic acid, was the most potent inhibitor of the incorporation in vitro of [U‐14C]glucose into cerebral lipids. These results indicated that these metabolites of phenylalanine were the more potent inhibitors of cerebral lipid metabolism in immature animals.
THE DISC ELECTROPHORETIC SEPARATION OF PROTEINS FROM VARIOUS PARTS OF THE GUINEA PIG BRAIN1
Authors: Ewart Davies W.
Published: October 2006

—Disc electrophoresis was used to study the saline‐soluble and detergent‐soluble proteins of various parts of the auditory pathway in the guinea pig brain. The five areas studied were the cochlear nucleus, olivary complex, inferior colliculus, medial geniculate and the auditory cortex. A study was also made of the proteins extracted from subcellular fractions obtained from guinea pig cerebral cortex.

The electrophoretic patterns showed small but significant differences in the five areas of the brain, both in the fast‐running acidic proteins and in the very slow‐moving proteins. The higher levels of the auditory pathway, to which the more complex information processing and storage is normally attributed, showed more complex electrophoretic patterns than the lower areas. Gross differences also occurred in the patterns of both the saline‐soluble and T‐X‐100‐soluble proteins of the subcellular fractions obtained by gradient density centrifugation. The simplest patterns were obtained from the myelin‐rich fraction and the mitochondrial fraction whilst the most complex patterns were given by the proteins of the nerve ending fraction and the cell soluble fraction.
RNA IN SINGLE IDENTIFIED NEURONS OF APLYSIA1
Authors: Price Peterson R.
Published: October 2006

—An investigation of the types of RNA present in the whole abdominal ganglia of Aplysia and in single identified neurons was made. Because of the long in vitro functioning of the ganglion and large size of the neurons, adequate labelled precursor was incorporated to allow gel electrophoretic or sedimentation analysis of RNA isolated from a single nucleus or from cytoplasm.

When labelled RNA is analysed a number of distinct peaks are found. Most of these are related to rRNA. In an effort to discern possible precursor‐product relations and localization of these RNA species, RNA from the nucleus and the cytoplasm of neuron R2 was analysed after varying lengths of labelling time with tritiated precursors, in some cases followed by incubation with actinomycin. The results support the notion of a large transcribed precursor which is subsequently processed to form finished rRNA. Differences in rate of rRNA maturation among neurons are indicated and a previously unreported 14 S molecule is described.
FURTHER EXPERIMENTS ON THE UPTAKE OF ACETYLCHOLINE AND ATROPINE AND THE RELEASE OF ACETYLCHOLINE FROM MOUSE BRAIN CORTEX SLICES AFTER TREATMENT WITH PHOSPHOLIPASES
Authors: Heilbronn Edith
Published: October 2006

—Uptake of acetylcholine (ACh) in mouse brain cortex slices, previously shown with ACh synthesized from tritiated choline is confirmed with acetyl[1‐14C]choline. Radioactivity from tritiated sodium acetate also accumulates in slices, but forms hardly any ACh. Uptake of ACh increases in a Ca2+‐free medium, decreases again upon addition of a 3 × 105 molar concentration of an anticholinergic benzilate compound and is completely blocked by the same compound at 3 × 103 m.

Slices preloaded with labelled ACh release, after extensive washing, some of their radioactivity into an outer medium free from ACh. Phospholipase, A or C, increases the release of radioactivity from the slices. An equilibrium is reached both with controls and phospholipase‐treated slices. Remaining radioactivity seems to be due to bound ACh. Calcium and magnesium ions have no effect on the uptake of tritiated atropine, although low concentrations of Ca2+ decrease the effects of phospholipase C on atropine uptake. The inhibitory effect of K+ on atropine uptake disappears completely after treatment with small amounts of phospholipase A, but even high concentrations of phospholipase C have no effect.
THE SUBCELLULAR DISTRIBUTION OF ACETYLCHOLINE, CHOLINE ACETYLTRANSFERASE AND CHOLINESTERASES IN LOBSTER WALKING LEG NERVES1
Authors: Welsch F. , Dettbarn W‐D.
Published: October 2006

—Nerve bundles from the walking legs of the lobster have been homogenized in either isosmotic or hyperosmotic sucrose solutions and subjected to differential and discontinuous density gradient centrifugation. The resulting subcellular fractions were analysed for their concentrations of acetylcholine (ACh), choline acetyltransferase (ChAc) and cholinesterase (ChE). Enzymic characteristics were used for a biochemical identification of the subfractions. Regardless of the osmotic conditions, ACh was always found in the free form; there was no evidence of any‘bound’ester. After ultracentrifugation of homogenates in the hyperosmotic medium a pellet floating atop was formed; it consisted of membrane fragments and contained more than 30 per cent of the choline‐esterhydrolysing enzymes, with a 3 to 4‐fold increased specific activity. ChAc was found to be increasingly soluble if the ionic concentration was raised to that of the haemolymph body fluid of the lobster. Thus, all the components of the ACh system were present in substantial amounts but the question of their physiological function remains open.
CHANGES IN POLYSOMES OF THE DEVELOPING RAT BRAIN
Authors: Yamagami S. , Mori K.
Published: October 2006

Abstract— Rat brain polysomes were prepared from a deoxycholate‐treated postmito‐chondrial supernatant in the presence of 2% bentonite and 1 mg/ml of yeast RNA to prevent partial degradation during preparation.

The polysomal preparations had an absorption maximum at 260 mμ and an absorption minimum at 235 mμ. The ratio of absorption maximum to minimum and the RNA to protein ratio were 1·58 and 1·06 respectively in 6‐day‐old rat brain polysomes. The sedimentation patterns showed six distinct peaks with sedimentation coefficients of 235S, 185S, 173S, 135S, 100S and 80S, indicating that these preparations have the characteristics of pure heavy polysomes.

The rate of [14C]phenylalanine incorporation into brain polysomal protein was maximal at approximately 10 days of age and decreased thereafter. A similar progressive reduction with increasing age was found in the stimulation of phenylalanine incorporation by the addition of 60 μg/tube of polyuridylic acid. However, the incorporation of phenylalanine into young rat brain polysomes was usually greater even with the addition of polyuridylic acid than in the older animals.

The comparative studies on sucrose density gradient centrifugation of polysomes between young and adult rat brains showed a considerable decrease of heavy polysomes in the older animals.

The effect of various factors on the stability of brain polysomes from both ages has been studied. The rates of RNA, protein and acid‐soluble phosphorus release from polysomes of the adult rat brains were usually greater in the presence of high salt concentration, ethylenediaminetetra‐acetic acid and urea than those from the corresponding preparations of younger animals. On the basis of evidence obtained from the above results it suggested that the adult brain polysomes were more unstable than those of younger animals.

The amount of polysomal RNA linearly increased up to the first 20 days after birth and then levelled off. The ratio of G + C/A + U of polysomal RNA was less in the young rat brains, falling to 1·30 as compared to 1·50 in older animals. The differences were statistically significant at less than a 1% level of confidence.

Polysomal preparations also contained RNase, phosphomonoesterase, phospho‐diesterase and 5′‐nucleotidase activities which cannot be washed off. The specific activities of these enzymes were generally higher in young rat brains than those in the adult.
KRAMPFAKTIVITÄT NACH INTRACEREBRALER INJEKTION VON l‐GLUTAMAT SEIZURES AFTER INTRACEREBRAL INJECTION OF l‐GLUTAMATE
Authors: Knaape H. H. , Wiechert P.
Published: October 2006

—In akuten Versuchen an nicht narkotisierten, relaxierten, aufgespannten Katzen löst stereotaktisch in verschiedene Hirnregionen injiziertes Natriumglutamat eine generalisierte bioelektrische Krampfaktivität aus. Von allen untersuchten Regionen wurde für den Hippocampus die niedrigste Krampfschwelle nachgewiesen. Andere Hirngebiete sowie der Ventrikel reagierten nicht Oder nur auf höhere Glutamat‐Konzentrationen mit einem Krampf. Als krampfauslösende Ursachen werden Konzentrationsverschiebungen im Glutaminsäurestoffwechsel diskutiert.

Abstract—

Sodium glutamate stereotactically injected into different cerebral regions of cats caused generalized electroencephalographic seizures. The hippocampus was shown to have the lowest seizure threshold of all regions investigated. Other cerebral regions and the ventricle did not react at all or only to higher concentrations of glutamate. Differences in the activity of the glutamic acid metabolism are discussed as releasing factors for seizures.
PREPARATION OF DNA AND FOUR DIFFERENT RNA SPECIES FROM RAT BRAIN. A NEW RNA FRACTION AND A NEW CHARACTERISTIC OF THE VARIOUS RNAs1
Authors: Oesterle W. , Kanig K. , Büchel W. , Nickel A.‐K.
Published: October 2006

Abstract—

A new modification is described for the fractionation of nucleic acids from brain. The cold phenol method followed by a hot extraction was combined with ‘salt‐precipitation’ and chromatography on Sephadex and Agarose gels. The method enables the isolation of five highly purified fractions in large amounts: DNA; high molecular weight salt‐soluble RNA, a hitherto undescribed fraction; rRNA; residual RNA (mRNA) and sRNA. All fractions showed, after 9 h in vivo incubation with 32P, different specific radioactivities and/or characteristic base compositions. The single mononucleotides of each RNA fraction differed markedly in their 32P‐labelling rate. This was found to be a new characteristic, for these differences were in no way similar in the various RNAs, but specific and constant for each fraction. An assay of base composition only by 32P‐labelling was therefore not possible.
PSYCHOTROPIC DRUGS AND THE METABOLISM OF INTRACEREBRALLY INJECTED TRYPTAMINE, 5‐HYDROXYTRYPTAMINE, AND NOREPINEPHRINE1
Authors: Meek J. L. , Krall A. R. , Lipton M. A.
Published: October 2006

Abstract— Rats were injected intracerebrally with labelled tryptamine, 5‐hydroxytrypt‐amine (5‐HT) and norepinephrine (NE). The disappearance of the amines and their metabolites as a function of time was determined. Tryptamine disappeared very rapidly, with a half‐life of 5 min in normal animals and of 45 min in rats treated with a monoamine oxidase (MAO) inhibitor. The level of radioactive 5‐HT declined in two phases, with half‐lives of 45 min and 3 h respectively. The 5‐hydroxyindoleacetic acid (5‐HIAA) that was formed disappeared with a half‐life of approximately 1 h. After inhibition of monoamine oxidase, there was only a single phase of 5‐HT disappearance (half‐life of 4 h). Reserpine decreased and imipramine increased the amount of 5‐HT remaining 4 h after injection. Of the NE injected, 12 per cent was converted to methoxyhydroxyphenylglycol sulphate (MHPGS), which disappeared with a half life of 3 h. Reserpine doubled the amount of methoxyhydroxyphenylglycol sulfate formed, but did not alter its rate of disappearance, its peak concentration occurring about 30 min after injection of NE in both control and reserpine‐treated rats.
SULPHATE METABOLISM IN ACUTE EAE1 RATS USING ISOLATED BRAIN PERFUSION TECHNIQUE
Authors: Vasan N. S. , Abraham J. , Bachhawat B. K.
Published: October 2006

—Metabolism of glycolipids and glycosaminoglycans were studied in rats in the acute stage of experimental allergic encephalomyelitis (EAE) using isolated brain perfusion technique. It was observed that there was a significant decrease in the concentration of cerebroside, sulphatide and GAG (hyaluronic acid and low sulphated GAG) when compared to normal and pairfed control rats. The radioactive sulphate incorporation into the cerebroside sulphate and sulphated GAG was significantly higher in the case of rats in the acute stage of EAE than the normal and pairfed control rats.
THE UPTAKE AND SUBCELLULAR DISTRIBUTION OF AROMATIC AMINES IN THE BRAIN OF THE RAT1
Authors: Baldessarini R. J. , Vogt Marcella
Published: October 2006

Abstract—

The hydroxylated phenylethylamines p‐tyramine, m‐tyramine, octopamine, metaraminol and norepinephrine were accumulated by homogenates of rat brain much more vigorously than β‐phenethylamine or amphetamine. The affinity concentrations (Km) for initial (5‐min) uptake by homogenates of whole brain were 0.5, 3 and 6 μM for DL‐norepine‐phrine, p‐tyramine and DL‐octopamine, respectively. The uptake of these three hydroxylated compounds was much more vigorous in striatal tissue than in cortical tissue, and in both tissues the rate of uptake decreased in the sequence: norepinephrine > tyramine > octopamine. The uptake of these three substances was inhibited by reduced temperature, by lack of glucose, by CN‐ and DNP, and by desmethylimipramine, cocaine and ouabain. The uptake of norepinephrine and octopamine appeared to require Na+. Pretreatment of rats with reserpine or 6‐hydroxydopamine decreased the ability of brain to take up norepinephrine or octopamine. Previously accumulated labelled phenylethylamines migrated in sucrose density gradients with a peak of radioactivity corresponding to an equilibrium position of catecholamine‐containing nerve endings. The magnitude of the retention of [3H]amine in this synaptosornal peak decreased in the order: norepinephrine > octopamine > tyramine. The accumulated amines were released by sonic, osmotic and thermal stresses which disrupt neuronal membranes. The presence of a β‐hydroxyl group appeared to protect amines from destruction by monoamine oxidase, presumably by virtue of uptake in presynaptic storage vesicles. During superfusion, tyramine and metaraminol appeared to displace [3H]norepinephrine from binding sites in brain slices.
A MICRO‐SCALE PROCEDURE FOR THE PREPARATION OF SUBCELLULAR FRACTIONS FROM INDIVIDUAL AUTONOMIC GANGLIA
Authors: Giacobini E , Hökfelt T , Kerpel‐Fronius S , Koslow S. H , Mitchard M , Noré B
Published: October 2006

Abstract— A microscale modification for the preparation of subcellular fractions employing milligram and submilligram amounts of neuronal tissue (brain nuclei and autonomic ganglia) is described.

Electron microscope characterization and enzymic studies were carried out on the six subcellular fractions of sympathetic ganglia of cat thus prepared.

The synaptosomal preparations obtained from individual ganglia were poorer in their nerve ending content than those obtained from brain by previous investigators. The highest RSA for AChE was found in layer L2 which was rich in membranes and vesicle components. ChAc activity was also highly concentrated in layers L2 and L3 (membranes, nerve ending‐like particles, mitochondria and ‘ghosts’). MAO activity was particularly high in the layers L4 and L5 which contained a large number of mitochondria. Layer L1 (membrane fragments) and particularly layer L6 which contained mainly collagen fibres, were low in activity of all three enzymes.

After preganglionic denervation, both ChAc and AChE activities were significantly reduced in the purest nerve ending fraction, L3 while MAO activity was practically unchanged.
THE MASS DISTRIBUTION OF THE PHOSPHATIDYLCHOLINES IN SUBCELLULAR FRACTIONS OF RAT BRAIN1
Authors: O'Brien J. F. , Geison R. L.
Published: October 2006

Whole brains from 20‐22‐day‐old rats were separated into the 15,000 g supernatant, myelin, nerve ending and mitochondrial fractions. Gas chromatography of the trimethylsilyl derivatives of 1,2‐diglycerides obtained by hydrolysis with phospholipase C of the phosphatidylcholine from each fraction showed marked differences of carbon number distribution (i.e. the sum of the carbon atoms in the two fatty acids of the diglyceride) among the different membranous fractions. Further characterization of each diglyceride was obtained by preparative gas chromatography of the diglyceride‐trimethylsilyl ethers and determination of the acyl moieties after collection, methanolysis and gas chromatography.

The results indicate that at least three distinct populations of phosphatidylcholine exist in the brain. Nerve endings and the 15,000 g supernatant fraction exhibit a very similar diglyceride pattern with dipalmitoylglycerophosphorylcholine representing over 30 per cent of the species present. Myelin has a unique phosphatidylcholine composition with much less polyenoic species in the 36 and 38 carbon number peaks. Mitochondria contain phosphatidylcholines with relatively more long‐chain polyunsaturated fatty acids. TLC of the phosphatidylcholines yielded partial separation into two spots, which differed in distribution of fatty acids. The faster migrating spot contained most of the polyenoic acids, whereas the slower migrating spot contained most of the palmitic, stearic and oleic acids.
PARTICULATE AND SOLUBILIZED FUCOSYL TRANSFERASES FROM MOUSE BRAIN
Authors: Zatz M. , Barondes S. H.
Published: October 2006

The transfer of [14C]fucose from GDP‐[U‐14C]fucose to endogenous and exogenous acceptors by particulate and solubilized preparations from mouse brain is described. Suspensions of brain microsomes incorporated [14C]fucose into a heterogenous group of glycoprotein products, which have a distribution on gel electrophoresis similar to those synthesized in vivo. Fucosyl transferase, extracted from brain microsomes by Triton X‐100, transferred [14C]fucose from GDP‐[U‐14C]fucose to terminal galactose residues exposed by mild acid hydrolysis of porcine plasma glycoprotein. Comparison of the specific activities of the solubilized fucosyl transferase from a number of organs showed that, in the presence of the exogenous acceptor which was used, the transferase of brain was more active than the transferases from all other organs tested, with the exception of kidney. Examination of subcellular fractions of brain, with endogenous and exogenous acceptors, showed that activity was limited to fractions containing microsomal membranes, whereas synaptosomal and other fractions were virtually inactive.
REGIONAL CHANGES IN BRAIN CATECHOLAMINES AFTER PROTON IRRADIATION OF THE STRIATE CORTEX IN THE SQUIRREL MONKEY
Authors: Hsu L. L. , Samorajski T. , Ordy J. M. , Bose H. , Curtis H. J.
Published: October 2006

To establish possible functional relationships between anatomically distinct cortical centres in primates, we compared changes in visual acuity, nucleic acids, protein, enzymes and catecholamines in cortical and subcortical areas six months after 10,000 and 20,000 rd of proton irradiation of striate area 17 of the visual cortex of the squirrel monkey. Minimum separable acuity was reduced from 1 minute of arc in controls to 4 minutes in the 20,000‐rd group. DNA, RNA and protein contents were not altered, but the activity of acetylcholinesterase was increased significantly in area 17. A decrease of norepinephrine occurred in the hypothalamus, hippocampus, caudate nucleus, putamen and brain stem of the irradiated brains. Since no ultrastructural basis has been found to account for these changes, we assume that a sustained chemical change occurred at the irradiated site and that the effect was transmitted to non‐irradiated regions of the brain.
THE BINDING OF BOTULINUM TOXIN TO MEMBRANE LIPIDS: PHOSPHOLIPIDS AND PROTEOLIPID
Authors: Simpson L. L. , Rapport M. M.
Published: October 2006

A number of phospholipids known to be constituents of nerve endings were tested for their ability to inactivate botulinum toxin. Substances tested included phosphatidylcholine, phosphatidalcholine, phosphatidylethanolamine, phosphatidalethanolamine, β‐acyl lysolecithin, sphingomyelin, phosphatidylserine, phosphatidic acid, phosphatidylinositol and cardiolipin. Proteolipid from bovine white matter was also tested. Neutral phospholipids potentiated the toxicity in vivo of botulinum toxin, but they had no effect on the toxicity in vitro. Some, but not all, acidic phospholipids caused loss of toxicity of botulinum toxin in solutions at low pH both in vivo and in vitro. However, none of these substances when incubated with toxin under physiological conditions of temperature, pH and ionic strength, caused loss of toxin potency. The data suggest that none of these phospholipids is likely to be a toxin receptor.
ENZYMIC STUDIES ON SULPHATIDE METABOLISM IN DIFFERENT STAGES OF EXPERIMENTAL ALLERGIC ENCEPHALOMYELITIS
Authors: Vasan N. S. , Bachhawat B. K.
Published: October 2006

Abstract— The activities of three enzymes–cerebroside sulphotransferase, 3′‐phospho‐adenosine 5′‐phosphosulphate synthesizing enzyme and arylsulphatases A and B have been studied in various developmental and recovery stages of experimental allergic encephalomyelitis. The concentrations of cerebroside and sulphatide were also analysed during these stages. It was observed that the sulphatide concentration decreased during the development of the disease, with a concurrent increase in the activity of arylsulphatase and vice versa during the recovery stages. 3′‐Phosphoadenosine 5′‐phosphosulphate synthesis as well as sulphotransferase activity increased during the pre‐acute stage of the disease, reached a maximum at the acute stage and decreased during recovery stages.
METABOLISM OF d‐[U‐14C]RIBOSE IN RAT TISSUES
Authors: Gaitonde M. K. , Arnfred T.
Published: October 2006

Abstract— d‐[U‐14C]Ribose injected subcutaneously into the rat enters the blood, liver and brain. At 30 min after injection 40‐70 per cent of the radioactivity in the brain was found in amino acids and only 2‐6 per cent in free sugars. In contrast, free sugars (mainly glucose) and carboxylic acids accounted for most of the radioactivity in liver and blood. Evidence for the entry of [U‐14C]ribose into the brain was obtained by intracarotid or intravenous injection of [U‐14C]ribose after interrupting the blood supply to the liver and kidney. Under these conditions the radioactivity in the brain was found in amino acids, carboxylic acids and ribose; no significant amount of [14C]glucose was detected in brain or heart. It is concluded that ribose is metabolized directly in vivo in the brain. d‐[U‐14C]Ribose was metabolized also by brain slices in vitro to form 14C‐labelled amino acids and carboxylic acids; the rate was equivalent to the utilization of 0.65 μmol of ribose/g/h. The specific radioactivity of glutamine and of γ‐aminobutyrate was similar to or higher than that of glutamate in the brain. These results are discussed in the context of metabolic compartments.
PREPARATION OF SUCCINIC SEMIALDEHYDE: ITS COLORIMETRIC ESTIMATION AS AN ASSAY FOR GABA AMINOTRANSFERASE
Authors: Taberner P. V. , Barnett J. E. G. , Kerkut G. A.
Published: October 2006

Abstract— A simple method is described for the preparation of succinic semialdehyde by the oxidation of 4‐hydroxybutyric acid with dimethyl sulphoxide in the presence of phosphorus pentoxide. The colorimetric estimation of succinic semialdehyde by condensation with 3‐methyl‐2‐benzothiazolinone‐2‐hydrazone is used as an assay for GABA aminotransferase activity in mouse brain. The values obtained for the specific activity of this enzyme in mouse brain using the colorimetric method agree with those obtained by the more conventional isotopic method.
CHOLESTEROL ESTERS IN DEVELOPING RAT BRAIN: CONCENTRATION AND FATTY ACID COMPOSITION1
Authors: Eto Y. , Suzuki K.
Published: October 2006

Abstract— The contents and the fatty acid composition of cholesterol esters were analysed in developing rat brain. The total content did not exceed 20 μg/brain throughout development. Elimination of serum by adequate perfusion was essential for accurate results. Two separate events appeared to affect the levels of cholesterol esters in developing rat brain, one probably reflecting general developmental changes and the other apparently related to myelination. On either a unit weight or a whole brain basis, the curves appeared to be a superimposition of the two events. There was an underlying developmental change, which was characterized on a unit weight basis by the highest level of cholesterol esters immediately after birth and a steady decline to the adult level by 30 days of age or which on the basis of whole brain was characterized by a steady increase throughout the development. A period of transient increase was superimposed on this underlying developmental change between the ages of 7 and 27 days and corresponded to the period of active myelination. The major fatty acids of rat brain cholesterol esters were palmitic, palmitoleic, oleic and arachidonic acids. Palmitic and palmitoleic acids decreased in proportion while oleic acid increased, as the animal matured. The fatty acid composition of serum cholesterol esters was distinctly different from that of brain cholesterol esters; those from serum contained much higher proportions of linoleic and arachidonic acids and much less palmitoleic and oleic acids.
DISTRIBUTION AND TURNOVER OF OCTOPAMINE IN TISSUES
Authors: Molinoff P. B. , Axelrod J.
Published: October 2006

Abstract— Octopamine is a normally occurring amine in several species of animals. Particularly high concentrations are found in the crustacean central nerve cord. In the rat it is specifically localized to sympathetic nerve endings, has a subcellular distribution similar to that of norepinephrine, and is asymmetrically distributed in the CNS. It has a turnover rate in heart about six times that of norepinephrine. The physiological role of octopamine has not been established but it appears likely that it is a cotransmitter together with norepinephrine in the peripheral sympathetic nervous system.
IMPAIRMENT OF GROWTH AND DEVELOPMENT OF THE RAT BRAIN BY HYPEROXIA AT ATMOSPHERIC PRESSURE
Authors: Grave G. D. , Kennedy C. , Sokoloff L.
Published: October 2006

Abstract— The continuous exposure of newborn rats to 70–80 per cent oxygen at atmospheric pressure throughout the iirst 9 days of life significantly inhibited the growth of the brain which normally occurs during this period of life. The accumulations of DNA, RNA, total protein, and proteolipid protein which accompany brain growth during this period were all approximately proportionately depressed by the oxygen‐enriched atmosphere. RNA/DNA and protein/DNA ratios were unaffected. The increase in brain mass in the first week of life reflects mainly cell proliferation, and since the decreased DNA accumulation occurred with no changes in RNA/DNA and protein/DNA ratios, we conclude that the effect of oxygen was to inhibit cellular division. We estimate that the oxygen exposure caused an approximately 7 per cent deficit in the cell population of the brain. These results indicate that the use of elevated concentrations of oxygen may have serious deleterious effects on the growth and development of the brain.
EXPERIMENTAL ALCOHOLISM IN RATS. EFFECT OF ACUTE ETHANOL INTOXICATION ON THE IN VITRO INCORPORATION OF [3H]LEUCINE INTO NEURONAL AND GLIAL PROTEINS1
Authors: Jarlstedt J. , Hamberger A.
Published: October 2006

Abstract— Ethanol administered in vivo or in vitro during incubation of brain slices was studied with respect to its effect on brain protein synthesis.

In the in vivo series the rats were given a single intraperitoneal injection of ethanol 3 h before death. Slices of cerebral cortex and liver were incubated in isotonic saline media containing [3H]leucine. Amounts of free and protein‐bound radioactivity were determined. Subcellular fractions and fractions enriched in neuronal perikarya and in glial cells were prepared from cortical slices subsequent to incubation, and the specific radioactivity determined for each cell type.

The incorporation of [3H]leucine into brain proteins was inhibited while incorporation into liver proteins was stimulated in ethanol‐treated rats. The levels of TCA‐soluble radio‐activity, however, did not differ between the ethanol group and the controls. In the fractionated material from cerebral cortex, the specific radioactivity in the neuronal fraction was unaffected by ethanol, while the radioactivity in the glial fraction was significantly depressed.

In vitro administration of ethanol induced a non‐linear response in both brain and liver, with depression of leucine incorporation into proteins of cerebral cortex at all concentrations used. When brain slices were exposed to ethanol in vitro, in concentrations corresponding to the in vivo experiments, a similar reduction of the leucine incorporation into the glial fraction was obtained. Incorporation of leucine into subcellular fractions from whole brain cortex was also investigated. The specific sensitivity of the glial fraction to ethanol is discussed in relation to the involvement of the different cell types with transport processes in the brain.
METABOLISM OF BEDS OF MAMMALIAN CORTICAL SYNAPTOSOMES: RESPONSE TO DEPOLARIZING INFLUENCES
Authors: de Belleroche J. S. , Bradford H. F.
Published: October 2006

Abstract— The metabolic properties of synaptosome beds (deposits positioned between nylon gauzes) were studied. They respired, glycolysed, produced ATP and phosphocreatine, and metabolized [U‐14C]glucose to glutamate, aspartate, alanine and GABA at similar rates to synaptosome suspensions. Metabolic inhibitors caused massive loss of amino acids from the beds. Synaptosome beds also responded metabolically to electrical pulses; respiration and lactate production increasing by 40 per cent. Differential release of glutamate, aspartate and GABA occurred during electrical stimulation, maximum release being after 10–15 min of stimulation. This differential release also occurred when medium potassium was increased. Omitting and chelating calcium reduced or abolished this response with both forms of stimulation. Including amino acid analogues (β‐aminobutyric acid, α, γ‐diaminobutyric acid and N‐acetyl glutamic acid) in the incubation medium changed the patterns of amino acids present in the medium, indicating that under normal conditions active amino acid uptake processes are occurring in synaptosomes. Tetrodotoxin and ouabain also interfered with amino acid release without greatly affecting the response to stimulation. Cerebral cortex slices incubated between gauzes also showed a glycolytic response to electrical stimulation. GABA was the only amino acid showing a significant increase in the amount released with both potassium and electrical stimulation of the slices.
THE ACYLATION OF L‐GLYCEROL‐3‐PHOSPHATE MICROSOMES FROM RAT BRAIN: EFFECTS ARISING FROM THE PROPERTIES OF THE REACTION MEDIUM1,2
Authors: Kuwahara S. S.
Published: October 2006

Abstract— The velocity of the reaction catalysed by acyl‐CoA: l‐giycerol‐3‐phosphate acyltransferase (EC 2.3.1.15) of microsomes from rat brain was affected by the nature of the buffering agent, the ionic strength and the sucrose concentration of the reaction medium. The enzyme was inhibited by buffers based on trimethyl‐pyridine, diethyl barbituric acid, and boric acid. Buffers based on N‐ethyl morpholine, potassium phosphate, sodium arsenate, imidazole, tris and triethanolamine were not inhibitory. Dithiothreitol protected the enzyme and produced maximal activity at levels in the reaction medium between 0.2 and 2.8 mM.

Optimum ionic strength was determined by varying the concentration of a potassium phosphate buffer and in this medium the optimum ionic strength was about 0.2 M. In other studies with sodium formate, potassium acetate and other salts there was a broad plateau of activity in a range about 0.2 M. A study of pH vs. activity with two different buffering agents at constant ionic strength showed a broad maximum of activity from pH 7.2 to pH 7.8. The velocity of the reaction could be further increased by the inclusion of 0.25 M‐sucrose in the reaction medium in the presence of 0.2 M salts. The sucrose effect produced maximum velocities at sucrose concentrations ranging from 0.2 to 0.6 M. The studies reported here indicate that the activity of the enzyme is dependent upon the state of hydration of the microsomal membranes and in part on the ability of the enzyme or membrane to cope with large micelles of S‐palmityl‐CoA.
Differences in the apparent molecular weight of soluble and mitochondrial hexokinases of rat brain
Authors: Teichgräber P. , Biesold D.
Published: October 2006

In Brain tissue only 10–20 percent of the total hexokinase activity (EC 2.7.1.1) is present in the cytoplasm whereas the particulate activity is associated with mitochondria (Bachelard, 1967; Teich‐graber, Biesold and Pigarewa, in press). Either small (Wilson, 1968) or insignificant kinetic differences (Thompson and Bachelard, 1970; Bigl, Müller and Biesold, 1971) between soluble and particulate enzyme activity have recently been reported. Though the DEAE cellulose column chromatography patterns of both hexokinases were reported to be similar (Thompson and Bachelard, 1970; Bigl, Müller and Biesold, 1971), differences were found between soluble and mitochondrial hexokinase after gel electrophoresis separation (Bachelard, 1967; Bigl, Muller and Biesold, 1971). Recently it has been shown in this laboratory that Triton X‐100 also enhances the hexokinase activity of the cytoplasm as has already been demonstrated for the mitochondrial form (in preparation).

The purpose of the experiments described here was to elucidate whether the soluble cytoplasmic hexokinase differs from the mitochondrial‐bound hexokinase in respect to its apparent molecular weight. To diminish the occurrence of experimental artefacts, different extraction procedures were employed. Furthermore, the effect of Triton X‐100 on the molecular weight was investigated in an attempt to reveal an explanation for the increase in enzymic activity after incubation of hexokinase with this detergent.
DISPOSITION OF FUCOSE IN BRAIN1
Authors: Margolis Renée K. , Margolis R. U.
Published: October 2006

Abstract— Labelled fucose administered to rats in vivo was rapidly incorporated into brain glycoproteins, but not into any other brain constituents, including glycolipids and acid mucopolysaccharides. Maximum incorporation of tritium‐labelled fucose into brain glyco‐proteins occurred 3–6 h after intraperitoneal injection in young or adult rats, and the half‐time for the turnover of glycoprotein‐fucose in young rats was approximately 2 weeks.

Within 3 h after the administration of either [1‐3H]fucose or fucose generally labelled with tritium, 75 per cent of the total acid‐soluble radioactivity in plasma and brain was found to be volatile, and by 24 h after injection more than 90 per cent of the acid‐soluble radioactivity was volatile. The tritium in labelled fiicose appears to undergo arapid exchange reaction with hydrogen atoms in body water, although the tritium in fucose glycosidically‐ linked to glycoproteins is biologically stable. The rapid disappearance of labelled free fucose from the plasma and tissues of the rat precludes the possibility of any significant degree of reutilization of labelled precursor, and provides support for other data indicating that the turnover of fucose in brain glycoproteins is relatively slow in comparison to that of hexosamine and sialic acid.

Activities of α‐L‐fucosidase in rat brain, with pH optima at 40 and 6.0, had essentially the same Km (4 × 10−4 M and 3.2 × 10−4 M, respectively) with p‐nitrophenyl‐α‐L‐fucopyranoside as substrate. Activities of both were competitively inhibited by L‐fucose. However, the Kt measured at pH 4 (1.9 × 10−2) was almost ten times greater than that measured at pH 6 (1.5 × 10−4).
THE ROLE OF BRAIN SEROTONIN IN DDT‐INDUCED HYPERPYREXTA
Authors: Peters D. A. V. , Hrdina P. D. , Singhal R. L. , Ling G. M.
Published: October 2006

Abstract— Administration of a single dose of p,p′‐DDT to rats resulted in a marked increase in the concentration of 5‐hydroxyindoleacetic acid in the brain stem. No significant change was observed in the amount of 5‐hydroxytryptamine (serotonin) following treatment with this insecticide. However, when p,p′‐DDT was given to pargyline‐treated rats, a significantly greater increase in serotonin was observed when compared to that with the monoamine oxidase inhibitor alone. The concomitant administration of p,p′‐DDT and dl‐p‐chlorophenylalanine not only blocked the observed rise in 5‐hydroxyindoleacetic acid but also suppressed almost completely the neurotoxic symptoms (hyperpyrexia, tremors and convulsions) seen with the pesticide. In contrast, DL‐6‐fluorotryptophan (a more specific inhibitor of serotonin synthesis) prevented the DDT‐induced rise in body temperature as well as the increase in hydroxyindoleacetic acid, but did not affect the occurrence of tremor and convulsions. Our data suggest that an increase in the turnover rate of brain serotonin may underlie the hyperpyrexia induced by p,p′‐DDT.
ISOLATION OF AN ACID‐SOLUBLE PROTEIN WITH LOW MOLECULAR WEIGHT FROM MONKEY BRAIN
Authors: Wedege E. , Reichelt K. L. , Kvamme E.
Published: October 2006

Abstract— The isolation of a perchloric acid‐soluble low molecular weight protein from brain of Macaca irus is reported. Sodium dodecyl sulphate polyacrylamide gel electrophoresis and gel isoelectric focusing indicate that the protein is free of impurities. The molecular weight, as determined by gel filtration and sodium dodecyl sulphate gel electrophoresis, is shown to be 10,400 and 9900, respectively. This is in agreement with the value of 10,700 obtained from amino acid analysis. The protein contains 27 per cent acid amino acids and 15 per cent basic amino acids. However, the relatively high amide content gives the protein a neutral nature as shown by isoelectric point determination using gel isoelectric focusing.
AN INHERITED DEFICIENCY IN NORADRENALINE BIOSYNTHESIS IN THE BRINDLED MOUSE
Authors: Hunt D. M. , Johnson D. R.
Published: October 2006

—A reduction in central and peripheral synthesis of noradrenaline has been demonstrated in mice hemizygous for the X‐linked brindled (Mobr) mutant in the mouse. The results are consistent with defective hydroxylation of dopamine to NA, arising either as a result of a primary genetic defect in the enzyme dopamine‐β‐hydroxylase or from the presence of a highly specific inhibitor of this enzyme in mutant mice. Associated with this deficiency of noradrenaline are an increase in the activity of tyrosine hydroxylase in the central nervous system and an increase in the active uptake of tyrosine (and other amino acids sharing a common uptake mechanism with tyrosine) across the blood‐brain barrier.
CHARACTERISTICS AND PRODUCTS OF A CELL‐FREE POLYPEPTIDE SYNTHESIZING SYSTEM FROM NEONATAL AND ADULT MOUSE BRAIN
Authors: Gilbert B. E. , Grove Barbara K. , Johnson T. C.
Published: October 2006

—The regulation of protein synthesis by ribosomes isolated from mouse brain tissue was studied using a cell‐free polyphenylalanine synthesizing system. Polypeptide synthesis was followed by assaying translocation and analysing the reaction products by BD‐cellulose chromatography. The brain ribosomal activity could be divided by these methods into two distinct steps : binding of aminoacyl‐tRNA to the ribosome and active translocation leading to subsequent polyphenylalanine synthesis. In comparison to initial binding of aminoacyl‐tRNA, translocation in the cell‐free system increased the incorporation of labelled phenylalanine by 10‐fold. An analysis of the reaction products clearly showed active ribosomal synthesis of oligophenylalanine from [3H]phe‐tRNA. Ribosomes isolated from neonatal brain tissue were 2–4 times as active as those obtained from adult brain tissue in polypeptide synthesis. In addition, polypeptides synthesized on the more active ribosomes from neonates tended to be of greater chain length than those from adult. Therefore, the maturation‐dependent decrease in ribosomal protein synthetic activity during neural development was shown to be directly associated with the ribosome particles.