bluuebunny/crossref_metadata_2025 huggingface dataset:
STIMULATION OF PIRIFORM‐ AND NEO‐CORTICAL TISSUES IN AN IN VITRO FLOW‐SYSTEM: METABOLIC PROPERTIES AND RELEASE OF PUTATIVE NEUROTRANSMITTERS
Authors: McIlwain H , Snyder S. H
Published: October 2006

Abstract— (1) Multiple samples from the piriform cortex and neocortex of the guinea pig were maintained in separate incubation vessels through which incubation solutions based on Krebs‐Ringer bicarbonate glucose media were caused to flow for chosen periods at specified rates.

(2) The tissues were held in defined positions in relation to electrodes; in some experiments electrical stimuli were applied and in others incubation media were changed with respect to their oxygen, K+ or glutamate content.

(3) With media flowing at 3–4 ml/min, the incubated tissues were similar in contents of K salts and phosphocreatine, and in rate of glycolysis to those incubated in non‐flowing media. The tissues responded to electrical stimulation by increase in glycolysis and decrease in phosphocreatine and K content.

(4) During pre‐incubation periods in non‐flowing media, samples of piriform cortex were exposed to solutions containing 3H‐labelled glycine, noradrenaline or 5‐hydroxytry‐ptamine and on anlaysis were found to contain the labelled compounds at concentrations four to seven times those of the surrounding media. The labelled compounds were gradually released into the flowing incubation media, and the release of noradrenaline and 5‐hydroxytryptamine was accelerated by electrical stimulation.

(5) Release of the two bases was also modified by added reagents and the course of their release is discussed in relation to other metabolic changes concomitantly observed.
INFLUENCE DE LA DEFICIENCE THYROIDIENNE SUR L'INCORPORATION IN VIVO DE LA l‐[3H]LEUCINE DANS LES PROTEINES DU CERVELET CHEZ LE JEUNE RAT THE EFFECT OF THYROID DEFICIENCY ON THE INCORPORATION OF l‐[3H]LEUCINE INTO PROTEINS OF THE CEREBELLUM IN THE YOUNG RAT
Authors: Dainat J , Rebiere A , Legrand J
Published: October 2006

Résumé— L'incorporation de la leucine dans les protéines du cervelet de jeunes rats normaux et rendus hypothyroïdiens dès la naissance par le propylthiouracile (PTU) a étéétudiée pendant la demi‐heure qui suit l'injection intraveineuse d'une dose de l‐[4‐3H]leucine proportionnelle au poids du corps. Chez les animaux hypothyroïdiens, à tous les stades étudiés (6,10,14 et 21 jours), les radioactivités spécifiques (RAS) des phases acido‐solubles du plasma et du cervelet sont plus élevées que chez les témoins. La RAS des protéines du cervelet est inférieure à 6 jours, 10 jours et 14 jours. La signification de cette diminution de l'incorporation de la leucine tritiée dans les protéines du cervelet est discutée en fonction des données d'ordre structural concernant le développement du cervelet chez l'animal hypothyroïdien.

—The incorporation of leucine into the proteins of the cerebellum of young rats, normal and made hypothyroid since birth by propylthiouracil (PTU), was studied during the half hour following the intravenous injection of a single dose of l‐[4‐8H]leucine proportional to the body weight. In the hypothyroid animals, at all stages studied (6, 10, 14 and 21 days), the specific activity of the label in the free leucine pool of the plasma and cerebellum was higher than in the controls. The specific activity of the cerebellar proteins was lower at 6, 10 and 14 days. The significance of this decrease in the incorporation of tritiated leucine into the cerebellar proteins is discussed in relation to the anatomical data concerning the development of the cerebellum in the hypothyroid animal.
BRAIN GLYCOGEN AFTER INTRACISTERNAL INJECTION OF SOME CORTICOSTEROIDS
Authors: Mellerup E
Published: October 2006

Abstract— Intracisternal injection of corticosteroids in rats had no effect on brain glycogen content. Intracisternal injection of corticosteroids and insulin increased brain glycogen only as much as insulin did alone. Inhibition of corticosteroid synthesis did not influence brain glycogen content.
Hexose and pentose phosphates in brain during convulsions1
Authors: Carl Juanita L. , King Lucy J.
Published: October 2006

The Metabolism of glucose via glycolysis and the citric acid cycle represents the chief source of energy supplies in the brain. However, enzymes for the metabolism of glucose via the hexosemonophosphate (O'Neill, Simon and Shreeve, 1965) and pentose phosphate (Dreyfus and Moniz, 1962) pathway are also present in brain. A major difficulty in studying intermediates of the hexose and pentose phosphate pathway in brain is their extremely low absolute levels. Recently, fluorimetric, enzymic assays for these substrates have been developed (Kauffman, Brown, Passonneau and Lowry, 1969), and these assays, combined with rapid freezing techniques (Lowry, Passonneau, Hasselberger and Schulz, 1964) have made it possible to study these intermediates in brains of mice. Electrically‐induced tonic‐clonic convulsions are associated with a striking increase in metabolic rate in brain, but phenobarbitone minimizes changes in metabolic rate during convulsions (King, Lowry, Passonneau and Venson, 1967). In order to determine whether or not levels of hexose and pentose phosphates are altered under these conditions, assays for these substrates have been carried out in brains of convulsing mice with or without administration of phénobarbital prior to stimulus.
RELATIONSHIP OF PHENYLALANINE TO SEIZURE THRESHOLD DURING MATURATION
Authors: Gallagher B. B.
Published: October 2006

—The effect on seizure threshold of the acute intraperitoneal administration of dl‐phenylalanine in varying doses to the albino rat at different ages was investigated. Seizure threshold was measured by the technique using the volatile convulsant, hexafluorodiethylether. The alterations in seizure threshold associated with administration of the amino acid were correlated with blood and brain levels of phenylalanine and tyrosine. In 3‐ to 4‐week‐old albino rats the reduction in seizure threshold was directly related to the amount of phenylalanine administered. The effect was detected at 30 min after injection and had returned to control levels by 2 hr after administration of 20 or 40 mg of Dl‐phenylalanine and by 3 hr following the injection of 80 mg. There was a decreasing susceptibility to reduction in seizure threshold associated with phenylalanine administration with increasing age of the animals. The time course of reduction in seizure threshold in the youngest animals was temporally related more to the rise and fall of concentrations of phenylalanine in brain than to plasma levels of phenylalanine. The seizure threshold in 10‐week‐old animals was not reduced in spite of comparable elevation of blood and brain phenylalanine to the levels effective in 3‐ to 4‐week‐old animals. The results have been discussed in relation to previous studies on chronic, oral administration of phenylalanine to the rat and to possible mechanisms of action.
TRANS‐SULPHURATION IN PRIMATE BRAIN: REGIONAL DISTRIBUTION OF METHIONINE‐ACTIVATING ENZYME IN THE BRAIN OF THE RHESUS MONKEY AT VARIOUS STAGES OF DEVELOPMENT
Authors: Volpe J. J. , Laster L.
Published: October 2006

—The regional distribution of methionine‐activating enzyme (ATP:l‐methionine S‐adenosyltransferase; EC 2.4.2.13) in the brain of the Rhesus monkey was determined at various stages of development.

Activity of the methionine‐activating enzyme was highest in pituitary gland, cerebellum and occipital grey matter, and lowest in areas rich in white matter: spinal cord, subcortical white matter, corpus callosum and optic chiasm. There was no marked change in activity in any area during development from the first‐trimester foetus to the juvenile animal. During the same period of development, activity of the methionine‐activating enzyme in the liver increased approximately four‐fold.

The findings are discussed in relation to those transmethylating enzymes and/or methylated products which have been studied in mammalian brain. The presence of high activity of the methionine‐activating enzyme in cerebellum and occipital grey matter suggests that previously unrecognized methylating processes may be important in the metabolism of these areas of brain.
The influence of adrenergic and cholinergic blocking drugs on the glycogen content of the brain in rats deprived of paradoxical sleep
Authors: Mršulja B. B. , Rakić L. M.
Published: October 2006

Recent studies have pointed out biochemical and pharmacological phenomena associated with the mechanism or mechanisms of sleep, especially in its paradoxical phase (Jouvet, 1964; Mandel, 1964). Our previous experiments have shown that paradoxical sleep (PS) deprivation leads to the fall of total glycogen content in certain regions of the brains of cats (Mršulja, Rakić and Radulovački, 1967; Mršulja and Rakić, 1968) and rats (Karadžič and Mršulja, 1969). It was shown that changes of glycogen content correspond to PS deprivation and that PS deprivation is a specific stress to which the CNS responds selectively. Alterations in the glycogen concentration in a number of different brain structures lead us to conclude that neural areas affected by PS deprivation are widely distributed.

Jouvet (1962) was one of the first to suggest that a neurohumoral mechanism may be concerned in the control of and characteristics of sleep. Experiments have shown that both cholinergic and adrenergic mechanisms may be involved in the initiation, maintenance and control of sleep. It has also been pointed out that paradoxical sleep can be started and maintained by cholinergic drugs (Matsuzaki, Okada and Shuto, 1967, 1968), blocked or reduced by anticholinergic compounds (Matsuzaki et al., 1968), and stimulated by noradrenaline or by its precursor, DOPA (Matsumoto and Jouvet, 1964).

Bowers, Hartmann and Freedman (1966) showed that the ACh level of the rat telencephalon decreases with PS deprivation while the levels of norpinephrine and serotonin remain the same (Barchas and Freedman, 1963). More recently, Pujol, Mouret, Jouvet and Glowinski (1968) found the increased turnover of cerebral norepinephrine during rebound of PS in the rat.

It is also of interest to point out that probably both adrenergic and cholinergic processes participate in the glycogenolytic effect of physostigmine (Mršulja, Terzić and Varagić, 1968). It was suggested that physostigmine initiates the cholinergic processes which then trigger off adrenergic processes.

The aim in the present work was to determine the glycogen content in certain brain regions of rats which were subjected to PS deprivation lasting 72 hr and treated with some cholinergic or beta‐adrenergic blocking agents, as well as with a catecholamine depleting drug.
EFFECTS OF NARCOTICS ON THE GIANT AXON OF THE SQUID1
Authors: Simon E. J. , Rosenberg P.
Published: October 2006

—Levorphanol (10‐3 M) reversibly blocked conduction in the giant axon of the squid and axons from the walking legs of spider crab and lobster. Similar concentrations of levallorphan and dextrorphan blocked conduction in the squid giant axon. Under the same experimental condition morphine caused an approximately 40 per cent decrease in spike height. Levorphanol did not affect the resting potential or resistance of the squid axon. Spermidine, spermine and dinitrophenol had little or no direct effect on the action potential nor did they alter the potency of levorphanol. Concentrations of levorphanol as low as 5 × 10‐5 M blocked repetitive or spontaneous activity in the squid axon induced by decreasing the divalent cations in the medium. After exposure to tritiated levorphanol, the axoplasm and envelope of the squid axon accumulated up to 500 per cent of the concentration of tritium found in the external medium, dependent on time of exposure, and other variables. At pH 6 the levels of penetration were 33‐50% of those found at pH 8, which correlates with our observation that levorphanol is about 33 % as potent in blocking the action potential at pH 6. The penetrability of levorphanol was not affected by spermidine, dinitrophenol or cottonmouth moccasin venom. Levorphanol did not alter the penetration of [C14]acetylcholine nor did it render the squid axon sensitive to it. The block of axonal conduction by compounds of the morphine series is discussed both as to possible mechanisms and significance.
EFFECTS OF NERVE STIMULATION ON THE METABOLISM OF RIBONUCLEIC ACID IN A MOLLUSCAN GIANT NEURONE
Authors: Price Peterson R. , Kernell D.
Published: October 2006

—In vitro experiments were performed in order to determine whether nerve stimulation would affect the RNA metabolism of an identified giant neurone (R2) in the abdominal ganglion of Aplysia californica. The electrophysiological activity of the neurone was continuously monitored with an intra‐ or extracellular microelectrode. The mere presence of an intracellular microelectrode inside the neurone had no significant effect on the incorporation of tritiated nucleosides into the RNA of the giant neurone. Prolonged electrical stimulation of ganglionic nerves, strong enough to elicit post‐synaptic spikes in the giant neurone, produced a marked increase in the amount of labelled RNA in the nucleus as well as in the cytoplasm. Electrophoresis studies suggested that this increase in labelling might concern RNA with molecular weights corresponding to ribosomal as well as to non‐ribosomal RNA.
ACID‐LABILE (AMIDE) NITROGEN METABOLISM OF BRAIN PROTEINS
Authors: Kometiani P. A. , Klein Ye. E. , Gvalia N. V. , Gotsdudze Ye. G.
Published: October 2006

Abstract—

When the TCA‐insoluble fraction of samples of rat brain was extracted with organic (lipid) solvents, a soluble protein fraction was obtained which was metabolically active in the release and uptake of ammonia. The total nitrogen content of this fraction increased during aerobic incubation of slices of cerebral cortex and in brain samples after electrical stimulation of the rats, but under these conditions the content of protein‐bound, acid‐labile (amide) nitrogen decreased. Treatment of rats with intraperitoneally injected camphor caused a decrease in the content of acid‐labile nitrogen both in the proteins extracted into lipid solvents from the TCA precipitate of brain tissue samples and in the residual, washed TCA precipitate. By contrast, after treatment of rats with pentobarbitone, the content of proteinbound, acid‐labile nitrogen increased in the lipid solvent extract but decreased in the residual, washed TCA precipitate. After electrical stimulation of rats, the content of acid‐labile nitrogen in proteins of subcellular particles isolated from homogenates of brain exhibited dissimilar changes from control level: a pronounced decrease in the crude nuclear fraction but no change or a slight increase in the crude mitochondrial and in the combined microsomal and supernatant fractions. When slices of rat brain were incubated aerobically in the presence of glucose, ammonia was transferred from free amino acids to the acid‐labile (amide) nitrogen of protein. Evidence was obtained indicating the participation of aspartate and purine nucleotides in this transfer.
EFFECTS OF ETHANOL ON THE ACTIVITY OF ADENOSINE TRIPHOSPHATASE AND ACETYLCHOLINESTERASE IN SYNAPTOSOMES ISOLATED FROM GUINEA‐PIG BRAIN
Authors: Sun A. Y. , Samorajski T.
Published: October 2006

Abstract—

Nerve ending fractions from guinea‐pig cerebral cortex contained more than one‐half of the Na‐K ATPase activity present in the original homogenate. Ethanol at concentrations ranging from 0·043 to 2·57 m inhibited the Na‐K ATPase to a significantly greater extent than the Mg‐activated ATPase or AChE. The inhibition of membrane‐bound Na‐K ATPase by ethanol was of the non‐competetive type and the activity of Na‐K ATPase was increasingly inhibited by alcohols of increasingly longer chain length. The ability of various alcohols to inhibit membrane‐bound Na‐K ATPase activity was correlated with their lipid solubility.
LACK OF CORRELATION BETWEEN THE ZINC‐IODIDE‐OSMIUM POSITIVITY OF CHOLINERGIC TERMINALS AND THE CHOLINERGIC TRANSMISSION IN THE SYMPATHETIC GANGLIA OF THE CAT
Authors: Pärducz Á. , Halász N. , Joó F.
Published: October 2006

—The aim of the experiments was to determine whether a direct correlation exists between cholinergic transmission and zinc‐iodide‐osmium (ZIO) positivity of the synaptic vesicles of the preganglionic terminals in sympathetic ganglia of the cat. It was found that hemicholinium (HC‐3) pretreatment with or without preganglionic stimulation did not cause any significant changes in the ZIO positivity of cholinergic nerve terminals. The authors suppose that there is no direct relation between the ZIO positivity of axon terminals and the functioning of cholinergic transmission.
EFFECT OF CYANIDE AND ELECTRICAL STIMULATION ON PHOSPHOINOSITIDE METABOLISM IN LOBSTER NERVES
Authors: Birnberger Anita C. , Birnberger K. L. , Eliasson S. G. , Simpson P. C.
Published: October 2006

The contents of phosphoinositides, ATP, glucose and lactate in leg and claw nerves of the lobster were determined. Nerves were also analysed after cyanide poisoning, after electrical stimulation, and 1 h after removing the leg from the lobster.

Cyanide poisoning decreased the levels of ATP and glucose and increased the content of lactate but did not alter the levels of phosphoinositides. Nerves left in situ for 1 h after disconnection from the central nervous system exhibited a decrease in the content of tri‐phosphoinositides (TPI) of 50 per cent, without changes in ATP, glucose or lactate. The TPI change was reversed after incubation for 1 h in oxygenated seawater.

Nerves labelled in vivo with 32P were removed and stimulated at 50 Hz for 5 min. The turnover of TPI phosphorus increased on stimulation in both normal and cyanide‐poisoned nerves. In contrast, turnover of ATP increased after stimulation in normal nerves but not in cyanide‐treated nerves.

We sought to determine whether polyphosphoinositides play a greater role in resting metabolism of the nerve or in the conducting mechanisms. Our results make more likely the involvement of TPI in permeability changes of neural membranes during excitation.
MEASUREMENT OF γ‐AMINOBUTYRIC ACID IN ISOLATED NERVE CELLS OF CAT CENTRAL NERVOUS SYSTEM
Authors: Otsuka M , Obata K , Miyata Y , Tanaka Yuriko
Published: October 2006

Abstract— A sensitive method for measuring γ‐aminobutyric acid (GABA) has been developed. This method consists of a combination of the enzymic GABA assay of Jakoby and Scott (1959) with the enzymic cycling technique of Lowry, Passonneau, Schulz and Rock (1961) and permits the measurement of as little as 2 × 10−14 mol of GABA. Using this method, GABA analyses were made on single isolated nerve cell bodies of different types from the CNS of the cat. Average GABA concentrations in these cell bodies were: spinal ganglion cells, 0.2 mm; spinal mononeurons, 0.9 mm; large cells of the ventral part of Deiters' nucleus, 2.7 mm; large cells of the dorsal part of Deiters’ nucleus, 6.3 mm; cerebellar nuclei cells, 6.0 mm; cerebellar Purkinje cells, 6.6mM; cerebral Betz cells, 2.5 mm.

The GABA concentrations in the isolated dorsal Deiters' cells were greatly reduced (1.7 mm) after the removal of the cerebellar vermis while those of the ventral Deiters' cells were unaffected by the denervation. These results suggest that GABA is concentrated within axon terminals, probably of Purkinje neurons, synapsing with the dorsal Deiters' cells. The results of GABA analyses on isolated nerve cells are discussed in relation to the relevant neuronal functions and the possible role of GABA as an inhibitory transmitter.
INCORPORATION OF RADIOACTIVE SULPHATE INTO SULPHATIDE DURING MYELINATION IN CULTURES OF RAT CEREBELLUM
Authors: Silberberg D. , Benjamins Joyce , Herschkowitz N. , McKhann G. M.
Published: October 2006

Abstract— Explants of rat cerebellum obtained 12‐24 h after birth were maintained in culture in Maximow assemblies. About 90 per cent of the cultures myelinated after 10–12 days in vitro. Cultures maintained for varying periods of time were exposed to [35S]Na2SO4; labelled sulphatide was recovered from the total homogenate. Preparation of a subcellular fraction with density properties corresponding to those of myelin indicated that labelled sulphatide appeared in this fraction. Cultures which were poorly‐myelinated always exhibited a lower rate of inccrpomtion than well‐myelmated cultures from littermate animals, but the distribution of labelled sulphatide into the ‘myelin’ fraction was similar in the two groups. The rate of incorporation of [35S]Na2SO4 into total sulphatide increased with the duration of the culture, with a low level of incorporation until the seventh day in vitro, followed by a sharp increase in rate up to the 21st day. This pattern resembles that observed for rat cerebellum in vivo.
ZONAL CENTRIFUGATION OF NEURONAL PERIKARYA AND ISOLATION OF NEURONAL MEMBRANES RICH IN ACETYLCHOLINESTERASE
Authors: Kuenzle C. C. , Pelloni R. R. , Kistler G. S.
Published: October 2006

Abstract— A method is presented that allows the isolation of neuronal perikarya of high purity and in good yield from rat brain. To this procedure is coupled a second isolation step which affords neuronal membranes in preparative quantities. The arrangement of the two isolation steps in tandem ensures that the final preparation has a high degree of purity with respect to both its neuronal origin and its membrane content. The membranes so obtained do not constitute plasma membranes but rather represent intracellular structures that are predominantly derived from endoplasmic reticulum and contain mitochondrial elements as well. During the process of membrane purification AChE is enriched four‐fold while cholinesterase is concurrently eliminated. The present method supplements the procedure reported by Morgan, Wolfe, Mandel and Gombos(1971) for the isolation of synaptosomal plasma membranes. It may also open access to a useful source of brain AChE.
THE EFFECT OF OPTIC TENTACLE REMOVAL ON THE TRANSMITTER CONTENT OF THE GIANT SEROTONIN CELL OF HELIX ASPERSA
Authors: Osborne N. N. , Cottrell G. A.
Published: October 2006

Abstract— There is a giant serotonin‐containing neuron in each metacerebral ganglion of the snail Helix pumntia. Much of the amine is localized in small granular vesicles (COTTRELL and OBSORNE, 1970) and evidence for serotonin having a transmitter role in each giant neuron is very strong (COTTRBLL, 1970a, b). It is shown that the content of serotonin in each giant neuron is reduced by ablation of the optic tentacle. Maximum depletion of amine (about 70 per cent) was observed at 6–8 days after the operation. Unilateral depletion followed removal of only one tentacle. To examine the observations more closely, electrophysiological experiments were also made to determine any neuronal connection between the tentacles and the serotonin‐containing neurons. No evidence was found for the presence of an axon from either giant neuron in the nerves leading to the tentacles. Stimulation of the nerves supplying the tentacles caused both depolarization and spike firing, and hyperpolarization and inhibition of the giant neurons. It is possible that the depletion of serotonin following ablation of the optic tentacles results from an interruption of the nerve fibres mediating in one or both of the observed types of input.
METABOLISM IN VIVO OF BRAIN GALACTOLIPIDS: THE JIMPY MUTANT
Authors: Druse Mary J. , Hogan E. L.
Published: October 2006

Abstract— The incorporation in vivo of [U‐14C]glucose into the galactolipids of the brain of control and Jimpy mutant mice was examined. Over a 24‐h period of incorporation there was no indication of an increased rate of turnover of brain galactolipids in the mutant. The Jimpy mutant was identified at ages prior to and at the inception of myelination (7–10 days post partum) with a coat marker (Tabby). There was similar total radioactivity in galactolipids of the Jimpy at these ages but a reduction to 13 per Cent of control at 13 days and to 6 per cent at 16 days of postnatal age. This devetopmental pattern of galactolipid synthesis in Jimpy brain is not in accord with a primary defect in the biosynthesis of cerebrosides and sulphatides.
THE EARLY POST‐NATAL DEVELOPMENT OF THE NEURONAL LYSOSOME1
Authors: Idoyaga‐Vargas V. , Santiago Josephine C. , Petiet Patricia D. , Sellinger O. Z.
Published: October 2006

Abstract— The hydrolysis of p‐nitrophenyl‐2‐acetamido‐2‐deoxy‐β‐d‐gluco‐(I) and β‐d‐galacto‐pyranoside (II) and of p‐nitrophenyl‐α‐d‐mannopyranoside (III) by neuronal cell bodies and glial cells isolated from the cerebral cortex of 18‐day‐old or adult rats was found to be equally efficient, with relative ratios of hydrolysis for I, II and III of approximately 10:1:0.5 in both cell types and at both ages. Homogenates of the neuronal cell bodies obtained from cerebral cortices of 3‐, 8‐, 12‐, 18‐ and 32‐day‐old rats were subjected to differential centrifugation and the subcellular localization of N‐acetyl‐β‐d‐glucosaminidase (EC 3.2.1.30) hydrolysing (I)] was compared to that of the mitochondrial marker, succinate‐INT‐ oxidoreductase (EC 1.3.99.1). A fraction in which N‐acetyl‐β‐d‐glucosaminidase exhibited maximal specific activity could be isolated at all ages, an observation indicating that the potential for active hydrolytic performance is incorporated into the neuronal lysosome very early post‐natally. The specific activities of N‐acetyl‐β‐d‐glucosaminidase and succinate‐ INT‐oxidoreductase reached their respective maxima at widely different times postnatally: at 10–12 days for the mitochondrial enzyme and at about 18 days for the glycosidase, a difference suggesting that in the cortical neuron lysosomes and mitochondria develop out of step. The mitochondrial, lysosomal and microsomal fractions obtained by differential centrifugation were subjected to equilibrium density centrifugation and the presence of two populations of N‐acetyl‐β‐d‐glucosaminidase‐bearing particles was demonstrated. Although their presence was readily apparent in the neurons from 8‐ and 12‐day old brains, it was difficult to discern their presence in the neurons from the 3‐ and the 18‐day‐old brains. In 8‐day‐old brains gradient fractions obtained from neurons containing N‐acetyl‐β‐d‐glucosaminidase of a specific activity up to 8‐fold higher than that of the enzyme in the original neuronal homogenate were examined by electron microscopy and the concentration of numerous lysosomes and derivative bodies in these fractions was verified. Our present study demonstrates the capability of the immature and developing neuron to tightly couple the pace of its degradative processes to that of its highly efficient and highly selective synthetic activities.
EFFECTS OF ELECTRICAL STIMULATION OF RAT MIDBRAIN ON 5‐HYDROXYTRYPTAMINE SYNTHESIS AS DETERMINED BY A SENSITIVE RADIOISOTOPE METHOD
Authors: Shields P. J. , Eccleston D.
Published: October 2006

Abstract— 5‐Hydroxytryptamine (5‐HT) synthesis has been determined in the rat brain by measuring the 5‐[3H]HT formed from [3H]tryptophan in the presence of monoamine oxidase inhibitor. Electrical stimulation in the region of the midbrain raphe nucleus increased formation of 5‐[3H]HT by over 100 per cent, although the level of endogenous 5‐HT and the concentration and specific activity of tryptophan were unchanged; the results are interpreted in terms of a two‐compartment model. The optimum stimulation parameters were determined. Three days after a single dose of the tryptophan hydroxylase inhibitor p‐chlorophenylalanine, stimulation increased 5‐HT synthesis by the same percentage as in untreated animals. It was also found that after the end of an hour's stimulation, synthesis returned to control values in under an hour. These results suggest that the rise in synthesis of the amine on stimulation is not due to induction of tryptophan hydroxylase, but more likely to an increase in the activity of existing enzyme.
FATTY ACID SYNTHETASE OF BRAIN: DEVELOPMENT, INFLUENCE OF NUTRITIONAL AND HORMONAL FACTORS AND COMPARISON WITH LIVER ENZYME
Authors: Volpe J. J. , Kishimoto Y.
Published: October 2006

Abstract— The activity of fatty acid synthetase was studied in the brain and liver of the developing rat. Synthetase activity in brain was considerably higher in foetal and suckling rats than in older animals However, except for a small transient rise in the perinatal period, activity in liver was low until weaning when a dramatic rise occurred. Activity in brain varied according to the quantity of dietary fat only in long‐term experiments, whereas in liver nutritional influences clearly predominated in determining the rapid developmental changes of synthetase activity. Administration of hydrocortisone diminished hepatic activity but did not change brain synthetase. In the hypothyroid state activity in brain and liver was consistently decreased. However, in the hyperthyroid state hepatic activity increased but activity in brain did not change. The relatively high activity of fatty acid synthetase during brain development has been discussed in relation to the critical role of this enzyme system in brain metabolism. The effect of the hypothyroid state on the activity of brain synthetase suggests the possibility of hormonal control of this enzyme activity. The responses of hepatic synthetase to the hormonal influences delineate a specific step by which these compounds may exert their effect on fatty acid biosynthesis.
SEPARATION OF CATECHOLAMINE STORING SYNAPTOSOMES IN COLLOIDAL SILICA DENSITY GRADIENTS
Authors: Lagercrantz H. , Pertoft H.
Published: October 2006

Abstract— Catecholamine storing particles mainly from rat brain hypothalamus and corpus striatum have been isolated by isopycnic centrifugation in density gradients made of colloidal silica. As markers, tritium‐labelled noradrenaline, endogenous noradrenaline and dopamine were measured. Cytochrome oxidase was determined as an indicator of mitochondria.

Two distinct populations of amine containing particles were recognized with densities of 1, 03–1.04 g/ml and 1, 045–1.065 g/ml in continuous isotonic gradients made of silica sol and a polymer. The light fraction was assumed to contain myelin fragments, light synaptosomes and possibly also catecholamine storage vesicles, while the other one was probably a heavy population of synaptosomes containing more mitochondria. Free mitochondria were found in a band at a density of 1, 09–1.11.

The distribution pattern in isotonic gradients was compared with that in density gradients made of silica sol and sucrose or sucrose alone. The heavy population of the catecholamine particles was found to have a higher density in hypertonic gradients. Furthermore these synaptosomes seemed to lose more mitochondria and catecholamines than those in isotonic gradients probably due to the hypertonicity.

The present results confirm similar findings by other workers separating brain sub‐ cellular particles in isotonic gradients of Ficoll and sucrose.

Colloidal silica solutions might be of value for analytical centrifugation of brain sub‐cellular particles, since it has a lower tonicity than sucrose, lower viscosity than Ficoll and furthermore it is very easy to handle. The silica sol is inexpensive and allows large scale work.
METABOLISM OF PUTATIVE TRANSMITTERS IN INDIVIDUAL NEURONS OF APLYSIA CALIFORNICA: AROMATIC AMINO ACID DECARBOXYLASE
Authors: Weinreich D. , Dewhurst Susan A. , McCaman R. E.
Published: October 2006

Abstract— The activities of aromatic amino acid decarboxylase (EC 4.1.1.26) in various ganglia, nerve trunks, and individual identifiable neurons of Aplysia culifornica were measured. The distribution of the decarboxylase enzyme is ubiquitous throughout the central nervous system of the Aplysia. Every Aplysia neuron tested contained some decarboxylase activity. The presence of this particular synthetic enzyme in an Aplysia neuron, therefore, cannot be used to classify these neurons as ‘aminergic’.
THE ISOLATION AND BIOCHEMICAL CHARACTERIZATION OF THREE SUBFRACTIONS OF MYELIN FROM CENTRAL NERVOUS TISSUE OF THE ADULT RAT1
Authors: McMillan P. N. , Williams N. I. , Kaufman B. , Day E. D.
Published: October 2006

Abstract— By techniques of isosmotic density gradient ultracentrifugation three subfractions of myelin were isolated from homogenates of whole rat brain at densities of 1.054 g/ml (myelin I), 1.060 g/ml (myelin II) and 1.066 g/ml (myelin III). The stability of these fractions was demonstrated by the zonal centrifuge profile analysis of recycled fractions. Examination of the three myelin subfractions by techniques of electron microscopy and thin layer chromatography detected no obvious morphological or chemical differences. However, analysis for protein, cholesterol, phospholipids and cerebrosides did reveal differences among myelin I, myelin II and myelin III. Myelin I contained relatively more cholesterol than II or III. Myelin III contained relatively more phospholipids than I or II. The cerebroside‐to‐protein ratios were the same in all three fractions. Quantitative differences in fatty acid composition (as detected by gas‐liquid chromatography) were also observed.
STUDIES ON DNA FROM NORMAL AND SCRAPIE‐AFFECTED MOUSE BRAIN
Authors: Adams D. H.
Published: October 2006

Abstract— DNA has been extracted from normal and scrapie affected mouse brain fractions, 48 h after the injection of [3H]thymidine precursors. The extracted DNA has been subjected to fractionation on hydroxyapatite columns and CsCl gradients. The specific activity of double stranded nuclear DNA is two to three times higher when extracted from scrapie‐affected brain than from normal brain, but there is no apparent difference in the number of counts associated with double stranded mitochondrial DNA extracted from similar numbers of normal and scrapie affected brains. DNA from the large granule fraction of scrapie affected brain contains a peak of counts, melting off hydroxyapatite columns before the double stranded peak, consistent with the presence in scrapie brain of trace amounts of a small single stranded DNA.
THE N‐ACETYL‐β‐d‐HEXOSAMINIDASES OF CALF AND HUMAN BRAIN
Authors: Robinson D. , Jordan T. W. , Horsburgh T.
Published: October 2006

Abstract— Multiple forms of calf brain N‐acetyl‐β‐hexosaminidases (β‐2‐acetamido‐2‐ deoxy‐d‐glucoside acetamidodeoxyglucohydrolase EC 3.2.1.30) were separated on starch gel electrophoresis at pH 5.8. The organ specific electrophoretic patterns did not depend on the cell fraction studied. Much of the activity is only separated with difficulty from particulate matter. Two major and one minor component were separated on DEAE‐cellulose chromatography at pH 5.8. Each component had both N‐acetyl‐β‐galactosaminidase and N‐acetyl‐β‐glucosaminidase activity. The ratio of these two activities was unaffected by the presence of N‐ethylmaleimide or dithiothreitol. The forms were also examined by isoelectric focusing when at least four components were recognized: isoelectric at 4.9, 6.0, 6.3 and 6.8. Interconversion of the 4.9 form to that isoelectric at pH 6.0 was noted during vacuum dialysis. Samples from normal human brain and from cases of Tay‐Sachs disease were also examined and the results compared.
PURIFICATION AND PROPERTIES OF MULTIPLE FORMS OF BRAIN ACETYLCHOLINESTERASE (EC 3.1.1.7)1
Authors: Chan S. L. , Shirachi D. Y. , Bhargava H. N. , Gardner E. , Trevor A. J.
Published: October 2006

—Approximately 70 per cent of the total AChE of bovine brain tissue was solubilized by repeated homogenization and centrifugation in 0.32 m sucrose containing EDTA. After ammonium sulphate fractionation, application of the enzyme preparation to an agarose affinity gel column effected a 700‐fold purification. Subsequent molecular filtration separated three active forms of AChE with molecular weights of 130,000, 270,000 and 390,000 with an average specific activity of 575 mmol of acetylthiocholine hydrolysed/mg of protein/h. The complete procedure represented an approximate 23,000‐fold purification of the enzyme from that in the original tissue homogenate. The three forms of AChE exhibited certain differences in properties, including apparent Km values, pH optima and sensitivity to inhibitory agents. Ancillary studies on less purified enzyme preparations by use of polyacrylamide gel electrophoresis and isoelectric focusing techniques also suggested that brain AChE exists in multiple forms.
THE INCORPORATION OF LABELLED ACETATE INTO CEREBROSIDE AND OTHER LIPIDS OF THE DEVELOPING MOUSE BRAIN
Authors: Kanazawa I. , Ueta N. , Yamakawa T.
Published: October 2006

—Cerebroside in the brain is highly localized in myelin and has a relatively slow turnover rate. The aim of this study was to evaluate the true cerebroside biosynthetic activity under conditions in which the degradation and reutilization of brain lipids were as small as possible. The 3‐week‐old mice were decapitated at 0·5, 1, 2·5, 5 and 15 min after the intraperitoneal injection of labelled acetate and the incorporation of radioactivity into each lipid class was examined. Even at 0·5 min, a considerable amount of radioactivity was found in simple lipids, especially in the free fatty acid fraction, and in the course of time the radioactivity of complex lipids increased. On the other hand, the incorporation of radioactivity into cerebrosides was extremely small throughout the experimental period. Results indicated that the low radioactivity of cerebroside might be due to its high content of long‐chain fatty acids which were weakly labelled. The radioactivity of the sphingosine moiety was also low. In short, one of the rate‐limiting steps of cerebroside synthesis in brain might exist in long‐chain fatty acid and sphingosine synthesis. In addition, the incorporation curves of each component of cerebroside were compared with each other and the difference of the incorporation pattern of non‐hydroxy fatty acids of cerebroside was noted.
REGIONAL CHANGES IN CNS LEVELS OF THE S‐100 AND 14‐3‐2 PROTEINS DURING DEVELOPMENT AND AGING OF THE MOUSE1
Authors: Cicero T. J. , Ferrendelliy J. A. , Suntzeff V. , Moore B. W.
Published: October 2006

The levels of the S‐100 and 14‐3‐2 proteins were determined in a number of regions of mouse brain at intervals from 1 day to 30 months of age. Both S‐100 and 14‐3‐2 were found in measurable amounts as early as the first day of postnatal age but did not begin to accumulate rapidly in the forebrain, brain stem and cerebellum of the mouse brain until some time between the 7th and 14th days. From days 14 to 28 the levels of S‐100 and 14‐3‐2 in each region continued to increase rapidly with the exception of the forebrain where the rate of accumulation of S‐100 appeared to lag considerably behind that in the other regions. The proteins continued to accumulate at a rapid rate until approximately 6 months of age.

From 6 to 30 months of age, the levels of 14‐3‐2 remained relatively stable in cerebellum, hippocampus and hypothalamus and appeared to decrease slightly in striatum and cerebral cortex. In the case of S‐100, the level of the protein increased in all regions of brain from 6 to 30 months but the increase was most pronounced in the hippocampus, hypothalamus and striatum. The principal conclusion derived from this study is that the biochemical development and aging of the central nervous system are regionally selective processes.
STUDIES ON CEREBRAL ENERGY METABOLISM DURING THE COURSE OF GALACTOSE NEUROTOXICITY IN CHICKS1
Authors: Granett Sandra E. , Kozak L. P. , McIntyre Jean P. , Wells W. W.
Published: October 2006

—At various times during a 2‐day study, the levels of adenine nucleotides and selected glycolytic intermediates were determined in brains of chicks fed a diet containing d‐galactose (40%, w/w). The levels of ATP and glucose 6‐phosphate had decreased by 9 h after initiation of the diet, whereas those of fructose 1,6‐diphosphate, 3‐phosphoglycerate, l‐α‐glycerophosphate, and lactate were not reduced until after 18 h had elasped. Although glucose 1‐phosphate was not appreciably affected, glucose and glycogen were depleted during the latter stages of the toxicity. The cerebral levels of 3′,5′‐cyclic AMP and citrate did not differ significantly between the two dietary groups at 48 h. The changes in the levels of cerebral glycolytic intermediates and high‐energy phosphates during ischemia indicated that the glycolytic rate was diminished in the chicks fed galactose and that high‐energy phosphate compounds were depleted sooner than in controls. After intraperitoneal injection of [14C]glucose, the specific radioactivity and levels of glucose in the plasma from chicks fed either diet were similar, whereas they were significantly reduced in the brains from galactosefed animals. We suggest that galactose interferes with the uptake of glucose into the brain and that this mechanism may be an important factor in d‐galactose‐induced neurotoxicity in the chick.
ENZYMIC SYNTHESIS OF PSYCHOSINE SULPHATE
Authors: Nussbaum J.‐L. , Mandel P.
Published: October 2006

—An enzyme which catalyses the synthesis of psychosine sulphate by the transfer of [35S]sulphate from 3′‐phosphoadenosine 5′‐phosphosulphate to galactosyl‐sphingosine has been demonstrated in the brain of the young mouse. The enzyme activity appears to be bound to a microsomal fraction which is spun down with the synaptosomes. The product of the incubation mixture has been characterized as psychosine sulphate by a variety of TLC separations and other chemical procedures. Several parameters (detergent, cations, substrate and 3′‐phosphoadenosine 5′‐phosphosulphate concentrations, pH and incubation time), affecting the 3′‐phosphoadenosine 5′‐phosphosulphate‐psychosine sulphotrans‐ferase activity, have also been investigated. In the normal mouse brain there is a maximum enzyme activity at 17–19 days after birth, which is the period of most rapid myelin formation. In the brains of Jimpy mice, mutants with myelin deficiency, the activity is reduced and reaches a maximum around the 13th day. The lower activity correlates with the small amounts of sulphatides in Jimpy mouse brains. The results are discussed and related to present knowledge of galactolipid biosynthesis.
GLYCINE DECARBOXYLATION IN THE CENTRAL NERVOUS SYSTEM
Authors: Uhr Marie Louise
Published: October 2006

Abstract— The regional and subcellular distribution of the glycine decarboxylation which occurs in the presence of tetrahydrofolate, NAD and pyridoxal phosphate, has been measured in CNS tissue of cat, sheep and rat. The activity appeared similar to that of liver. It was located within mitochondria, and distributed regionally and subcellularly in the same manner as succinate dehydrogenase, a mitochondrial marker. Activity was low in pons, medulla and spinal cord, and was not affected by a number of drugs, some of which excite and some of which depress the activity of the CNS. All evidence suggests that glycine decarboxylation plays no direct role in glycine inhibitory transmission.
SOME PHYSICAL PROPERTIES OF BOVINE ADRENAL MEDULLARY DOPAMINE β‐HYDROXYLASE
Authors: Foldes A. , Jeffrey P. L. , Preston B. N. , Austin L.
Published: October 2006

(1) Dopamine, β‐hydroxylase (EC 1.14.2.1) was purified from bovine adrenal medullae according to the method of Foldes, Jeffrey, Preston and Austin (1972).

(2) The kinetics, pH optimum and the effect of Cu2+ ions on the purified enzyme were found to resemble those of the enzyme isolated by more involved procedures.

(3) The sedimentation coefficient (s20) of the homogeneous enzyme in 10 mM‐phosphate buffer, pH 7·2, containing 0·1 M‐NaCI was found to be 10·24 ± 0·12 (S.E.M. of 10 determinations).

(4) The effect of pH on the mol. wt. of the enzyme was investigated and no large deviation was found from the native mol. wt. of 290,000 in the pH range 3·9 to 11·1.

(5) The amino acid analysis of dopamine β‐hydroxylase is presented, and is contrasted to that of chromogranin A purified from the same chromaffin granule lysate.

(6) Treatment with either 8 M‐urea or 0·1% (w/v) sodium dodecyl sulphate was found to dissociate the enzyme into three similar, non‐active subunits, each of mol. wt. of the order of 100,000.
THE CONTRIBUTION OF AXOPLASMIC FLOW IN OPTIC NERVE AND PROTEIN SYNTHESIS WITHIN THE OPTIC TECTUM TO SYNAPTIC MEMBRANE PROTEINS OF THE CHICK OPTIC TECTUM1
Authors: Carton H. C. , Appel S. H.
Published: October 2006

In the 5‐day‐old chick, radioactive leucine was incorporated into proteins of synaptosomal and subsynaptosomal fractions both by fast axoplasmic flow and synthesis within the optic tectum. The distribution of radioactivity in subsynaptosomal fractions suggested that both pathways contribute to the protein constituents of each fraction. The relative contributions to each fraction were similar except for the supernatant proteins, for which fast axoplasmic flow contributed less than the synthesis within the optic tectum. The qualitative contribution of fast flow and synthesis within the optic tectum to the synaptic membrane fraction was distinctive. Fast axoplasmic flow preferentially labelled the high molecular weight proteins, whereas synthesis within the optic tectum labelled a larger percentage of smaller molecular weight proteins.
Lack of dihydrofolate reductase activity in brain tissue of mammalian species: possible implications1
Authors: Makulu D. R. , Smith E. F. , Bertino J. R.
Published: October 2006

IT IS becoming increasingly clear that folates play a vital, yet until recently an unrecognized, role in the development and function of the brain. Thus several groups of patients have been found with severe maldevelopment of the brain and mental retardation associated with inborn errors of folate metabolism resulting from congenital deficiency in one or more enzymes involved in folate metabolism (ARAKAWA et al., 1965; 1966; 1967; MUDD, LEVY and ABELES, 1969; ARAKAWA, 1970). The presence of folate coenzymes in brain tissue has been reported by several investigators (ALLEN and KLIPSTEIN, 1970; MCCLAIN and BRIDGERS, 1969). MCCLAIN and BRIDGERS (1969) showed that much less of the folates in brain are in the form of the N5‐methyl derivatives than is the case for folates in plasma, red blood cells and liver. Appreciable activity of several folate interconverting enzymes have been demonstrated in brain tissue; for example, N5‐methyl tetrahydrofolate homocysteine methyl transferase has been found to exist in higher levels in brain than in liver or kidney (MANGUM, 1972); N5‐methyl FH,N‐dimethyl‐dopamine methyl transferase (LADURON, 1972) and serine transhydroxymethylase (EC 2.1.1; L‐Serine: tetrahydrofolate 5, 10‐hydroxymethyl transferase) (BRIDGERS, 1968) have recently been detected in brain. The last enzyme is known to catalyse a reaction responsible for the generation of a major portion of one‐carbon units. In mouse brain, the activity of this enzyme declines during the first 2 weeks of extra‐uterine life (BRIDGERS, 1968).

The aim of the present study was to determine the levels of dihydrofolate reductase(5,6,7,8‐tetrahydrofolate:NADP+ oxidoreductase; EC 1.5.1.3) in mammalian brain tissues in comparison to the levels in other tissues. This enzyme occupies the first and key position in folate metabolism, reducing the metabolically inert vitamin, folic acid, to tetrahydrofolate. This enzyme also functions in thymidylate synthesis to regenerate tetrahydrofolate from dihydrofolate, a product of the reaction (HWHREYS and GREENBERG, 1958). In this reduced state the molecule can accept one‐carbon units from various sources to give rise to metabolically active coenzyme forms of folate. This communication reports the complete absence of dihydrofolate reductase in brain tissue of several mammalian species.