bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF 5‐PHENYLOXAZOLIDINEDIONE ON SODIUM–POTASSIUM–MAGNESIUM‐ACTIVATED ADENOSINE TRIPHOSPHATASE ACTIVITY IN MOUSE BRAIN1
Authors: Brink J. J. , Freeman Ellen A. 
Published: October 2006

Abstract—10 μm 5‐Phenyloxazolidinedione (PKO) stimulated Na–K–Mg‐ATPase activity in mouse brain homogenates by 45%. This activation effect was also observed for trimethadione and dimethadione. Inhibition of Na–K–Mg‐ATPase by 0.1 mm ouabain was reduced in the presence of PKO. When PKO (4 mg/kg) was administered to mice intravenously, maximum levels of 2 μg (10 nmol)/g were attained in the brain within 15 min. PKO had an ld50 of 872 mg/kg and an ed50 of 375 mg/kg for protection against metrazol‐induced seizures in mice.
EFFECTS OF GAMMA‐HYDROXYBUTYRIC ACID AND OTHER HYPNOTICS ON GLUCOSE UPTAKE IN VIVO AND IN VITRO
Authors: Taberner P. V. 
Published: October 2006

Abstract— (1) The effects of gamma‐hydroxybutyrate, imidazole‐4‐acetic acid and pento‐barbitone on mouse brain glucose, glycogen and lactate levels have been studied. All the drugs significantly increased the brain glucose content, but did not significantly alter brain glycogen levels. The increase in brain glucose following imidazole‐4‐acetic acid or hypnotic doses of pentobarbitone was matched by corresponding decreases in the lactate level; this was not the case with gamma‐hydroxybutyrate where the total glucose equivalents in the brain, expressed as the tissue level of (glucose) + (lactate/2), were significantly increased.(2) All drugs except imidazole‐4‐acetic acid significantly decreased the rate of appearance of [14C]glucose into the bloodstream in vivo but had no effect on the uptake of glucose into rat diaphragm in vitro when present at 2·5 mM concentration.(3) Only imidazole‐4‐acetic acid significantly inhibited glucose uptake into the brain in vivo but at 2·5 mM had no significant effect on glucose uptake into rat cerebral cortical slices in vitro.(4) It is concluded that the very large increase in brain glucose level observed following the injection of hypnotic doses of gamma‐hydroxybutyrate cannot be explained in terms of an increased net uptake of glucose into the brain.
DISTRIBUTION OF SERUM PROTEINS AND BETA‐TRACE PROTEIN WITHIN THE NERVOUS SYSTEM
Authors: Olson J‐E. , Link H. 
Published: October 2006

Abstract— The concentration of beta‐trace protein, a low molecular weight water‐soluble protein, was significantly higher in cerebral and cerebellar white matter than in grey matter. A similar distribution was found for transferrin. The concentrations of gamma‐trace protein and pre‐albumin were almost constant in cerebral and cerebellar white and grey matter. A different distribution was shown for albumin, betalc/betalA globulins, and the immunoglobulins G, A and M, with the highest concentrations mostly encountered in the highly vascularized basal ganglia and grey matter, and the lowest concentrations in white matter. Thus, different parameters, hitherto unknown determine the distribution within the central nervous system of various proteins‐those which originate from serum, and beta‐trace protein which originates mainly from the central nervous system.The amounts of the different proteins were higher in the choroid plexus than in brain tissue, with the exception of gamma‐trace protein.Foetal brains contained increasing concentrations of beta‐trace protein and of transferrin with age.Femoral nerve contained lower concentrations of beta‐trace protein and gamma‐trace protein, and higher concentrations of the other proteins, than the central nervous system.
Developmental changes of cholesterol ester hydrolases localized in myelin and microsomes of rat brain1
Authors: Eto Y. , Suzijki K. 
Published: October 2006

AbstractWe Previously demonstrated two distinct cholesterol ester hydrolases in rat brain (Eto and Suzuki, 1971). One of the two hydrolases had a pH optimum of 6·6 and showed a bimodal subcellular distribution, in microsomes and myelin. A substantial activity of this enzyme was present in newborn rat brain. The activity remained relatively unchanged during the first 12 days and then increased sharply, concomitant with the period of active myelination (Eto and Suzuki, 1972a). The more recent investigation, however, clearly demonstrated that this pH 6·6 cholesterol ester hydrolase actually consists of two distinct cholesterol ester hydrolases, one primarily localized in microsomes and the other almost exclusively localized in the myelin sheath (Eto and Suzuki, 1972b, 1973). The microsomal hydrolase had a pH optimum of 6·0 and was activated by sodium taurocholate and Triton X‐100, particularly by the latter. The myelin enzyme had a pH optimum of 7·2. It was activated by sodium taurocholate but slightly inhibited by Triton X‐100. These new findings suggested that the previously reported developmental curve of the pH 6·6 cholesterol ester hydrolase was probably a composite of developmental changes of these two distinct cholesterol ester hydrolases. We report here the findings which confirm the above prediction and update the information regarding the developmental changes of the enzymes involved in cholesterol ester metabolism in rat brain.
On the loss of gangliosides by dialysis
Authors: Kanfer J. N. , Spielvogel Christine 
Published: October 2006

The Gangliosides represent a family of sialic acidcontaining sphingoglycolipids which have ceramide (N‐acyl‐sphingosine) as the basic hydrophobic portion (Svennerholm, 1972). A heteropolysaccharide is glycosidically linked through the primary hydroxyl group of ceramide and the aldehyde of glucose. There are usually three or four different carbohydrates and up to a total of seven in the chain. The isolated gangliosides are soluble both in organic and aqueous solvents presumably because of their content of both hydrophobic and hydrophilic groups. The most commonly employed extraction procedure is based upon their solubility in chloroform‐methanol (2: 1, v/v) and subsequent partitioning into an aqueous methanol phase (FOLCH, LEES and SLOANE‐STANLEY, 1957). This methanolic solution is then dialysed against water to remove small molecular‐weight contaminants. This paper reports the loss of gangliosides upon dialysis when they are present at low concentrations.Gangliosides were prepared from fresh calf brain as previously described (Kanfer, 1969) and contained 25‐25% GMl, as judged by quantitative thin‐layer chromatography (Suzuki, 1964). GM2 was prepared from this material by treatment with neuraminidase as previously described (Kolodny, Brady, Quirk and Kanfer, 1970) and purified by the procedure of Winterbourne (1971). GM2 was isolated from brain tissue of a Tay‐Sachs child provided by Dr. B. Volk. Thin‐layer chromatography was carried out on Analtech Silica Gel G plates (Analtech Co., Wilmington, Del.) with chloroformmethanol‐2.5 N NH4OH (60 : 30 : 8, by vol.) as developing solvent. Total sialic acid was quantified by the resorcinol procedure according to Suzuki (1964). Duplicate known quantities of gangliosides were dissolved in 2 ml of methanol 41 M KCI(1 : 1, v/v) and dialysed overnight in untreated Visking tubing (0.22‐in. dia.; Fisher Scientific Co., Pittsburgh, Pa.; Cat. No. 1000) against a 500‐fold vol. of distilled water at 4°C. The contents of the sacs were removed and the total volume was measured; a 10‐1 5 per cent increase in volume was usually observed. Portions were analysed in duplicate for total sialic acid content, and the remainder was lyophilized for examination by TLC.
PROTEIN SYNTHESIS BY HIGHLY AGGREGATED AND PURIFIED POLYSOMES FROM YOUNG AND ADULT RAT BRAIN
Authors: Fellous Arlette , Francon J. , Nunez J. , Sokolof L. 
Published: October 2006

AbstractThe state of aggregation and the activity of polyribosomes as well as the activity of the pH 5 enzyme fraction were studied at two stages of postnatal brain development, 9 and 50 days after birth. When the polyribosomes were prepared at 0°C in the presence of 5 mm‐Mg2+, more than 85 per cent of the polyribosome material exhibited a sedimentation coefficient higher than 110 S. High Mg2+ concentrations are, therefore, unnecessary to obtain highly aggregated brain polyribosomes. The basal amino acid incorporating activity of both 9‐ and 50‐day‐old rat brain preparations is at least equal to that of rat liver. When prepared by the same procedure as above, 9‐day‐old rat brain polyribosomes seem to be more active (20 per cent) than those of adult brain. However, this difference in activity depends on the presence of a non‐ribosomal inactive contaminant which is always present in higher amounts in adult brain preparations. When purified from this contaminant, the preparations do not differ in activity. High Mg2+ concentrations are also not necessary for optimal protein synthetic activity and, in fact, are inhibitory. When assayed with both types of highly aggregated polyribosomes, the pH 5 enzyme fraction from adult brain is clearly less active than that of 9‐day‐old rats.These results suggest that the loss of brain protein synthesis during development does not depend on the stability of the messenger RNA‐ribosome complex but only on the soluble pH 5 enzyme fraction.
Accumulation of adenosine 3′,5′‐monophosphate in incubated slices from discrete regions of squirrel monkey cerebral cortex: effect of norepinephrine, serotonin and adenosine
Authors: Skolnick P. , Huang M. , Daly J. , Hoffer B. 
Published: October 2006

AbstractTHE ROLE of adenosine 3′5′‐monophosphate (cyclic AMP) in the central nervous system is as yet unknown. However, a variety of putative neurotransmitters such as norepinephrine, serotonin and histamine have been found to elicit enhanced accumulations of cyclic AMP in cerebral cortical slices from a variety of species (SHIMIZU and DALY, 1972; FORN and KRISHNA, 1971; SHIMIZU, TANAKA, SUZUKI and MATSUKADO, 1971; FUMAGALLI, BERNAREGGI, BERTI and TRABUCCHI, 1971). In addition, depolarization of membranes in cortical slices elicits a marked accumulation of cyclic AMP, probably mediated through the action of adenosine (KAKIUCHI, RALL and MCILWAIN, 1969; SHIMIZU. CREVELING and DALY, 1970). These results, obtained with grey matter from the entire cerebral cortex, suggest an intimate relationship between neuronal activity, release of putative neurotransmitters, and enhanced accumulation of cyclic AMP in brain tissue. Since innervation and electrical activity in the cerebral cortex differs among functionally distinct neocortical areas and in the histologically distinct limbic cortex, it appeared possible that these differences would also be manifest in the regional control of cyclic AMP levels. We now report that the response of the cyclic AMP generating system to putative neurotransmitters and adenosine does differ among discrete functional regions of the squirrel monkey cerebral cortex.
ULTRAVIOLET ABSORPTION CHARACTERISTICS OF MYELIN FROM THE CENTRAL NERVOUS SYSTEM
Authors: Gent W. L. G. , Gregson N. A. , Lovelidge Carol A. , Winder A. F. 
Published: October 2006

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

Abstract—Gangliosides and allied neutral glycosylceramides were isolated from human infant (2‐24 months of age) cerebral cortex and white matter. The individual glycolipids were separated quantitatively by a combination of column and thin‐layer chromatographic methods on silica gel, DEAE‐cellulose and Sephadex G‐25. In cerebral cortex GD1a and GM1 were the major fractions and constituted more than 70 per cent of the total gangliosides. The concentrations of neutral glycolipids, except for galactosylceramides, were very low: lactosylceramide and glucosylceramide comprised 30 and 5 nmol/g wet weight, respectively. In white matter their concentrations were 10 times higher. The ganglioside concentration was only 50 per cent of that in cerebral cortex: the difference was accounted for mainly by the much lower content of the major di‐ and trisialogangliosides.Stearic acid was the predominant fatty acid of all brain gangliosides. GM3, and GD3 had a considerable content of the very long‐chain fatty acids, C22‐C24, particularly in the white matter. Glucosylceramide and lactosylceramide had almost identical fatty acid patterns between each other in cerebral cortex and white matter. In the cerebral cortex stearic acid and in the white matter the very long‐chain acids predominated. d20:1 Sphingosine comprised more than 20 per cent of total sphingosine in all the gangliosides of the Gl‐ and G2‐series. GM3, and GD3 like lactosylceramide contained significantly less of d20:1 sphingosine. The findings suggest the existence of separate compartments for the biosynthesis of the gangliosides. Glucosylceramides and lactosylceramides of white matter have the same ceramide composition as the galactosylceramides with normal fatty acids and are thus unlikely to be intermediates in the metabolism of the major brain gangliosides which have a completely different fatty acid composition.
AMINO ACIDS AS CENTRAL NERVOUS TRANSMITTERS: THE INFLUENCE OF IONS, AMINO ACID ANALOGUES, AND ONTOGENY ON TRANSPORT SYSTEMS for l‐GLUTAMIC AND l‐ASPARTIC ACIDS AND GLYCINE INTO CENTRAL NERVOUS SYNAPTOSOMES OF THE RAT1
Authors: Bennett J. P. , Logan W. J. , Snyder S. H. 
Published: October 2006

Abstract—The accumulation by synaptosomal fractions from rat central nervous system tissue of transmitter candidate amino acids and non‐candidate amino acids was studied with respect to ionic requirements, metabolic inhibitors, structural analogues, and ontogeny. For l‐glutamic and l‐aspartic acids in cortex and spinal cord and glycine in spinal cord a stringent sodium requirement for high affinity uptake was demonstrated. Detailed kinetic analysis of the sodium requirement for glutamic acid uptake into cortical synaptosomal fractions suggests that: (1) sodium ion acts both competitively and non‐competitively in determining the velocity of high affinity uptake; (2) in the absence of sodium ion only the low affinity uptake can be demonstrated; and (3) inhibition of the Na–K‐ATPase enzyme system with ouabain reduces the velocity of uptake to 60% of control values in contrast to alanine whose synaptosomal uptake is less dependent on this enzyme system. No potent inhibitors of l‐glutamic acid accumulation were found among several structural analogues or derivatives. The kinetic analysis for glycine accumulation was more complex and suggested allosteric interactions between glycine and sodium ion. Developmental studies revealed GABA and l‐glutamic acid to have absolute sodium requirements for cortical synaptosomal accumulation from the 16th gestational day through adulthood, with glycine accumulation showing a decreasing sodium requirement as maturation proceeded over this period. The combined evidence suggests that sodium requirement for high affinity uptake is a characteristic of neuroactive substances and may be used as a screening tool to search for other neurotransmitter candidates.
STUDIES OF MONOAMINE OXIDASES1: PROPERTIES OF THE ENZYME IN BOVINE AND RABBIT BRAIN MITOCHONDRIA
Authors: Achee F. M. , Togulga G. , Gabay S. 
Published: October 2006

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

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

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

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

Abstract—Cholesterol, desmostcrol and squalene‐2(3)‐epoxide‐lanostcrol cyclase were assayed in various regions of human foetal brain from 10 to 22 weeks gestation. The cerebellum, thalamus and hypothalamus, and the ‘remainder’ of the brain were analysed. The proportion of desmosterol to cholesterol was highest in the thalamus and hypothalamus and lowest in the cerebellum. It is suggested that the ratio of desmosterol to cholesterol gives an indication of the state of maturity of a given region, particularly with respect to myelination. Thus the higher levels of desmosterol detected in the thalamus and hypothalamus may be correlated with earlier myelination in this region compared to the cerebellum which myelinates much later in development.Squalene‐2(3)‐epoxide‐lanosterol cyclase activity in whole brain showed three phases during the period studied; an initial low level up to 15 weeks, a slight increase in activity from 15 to 18 weeks (corresponding to neuroblast multiplication) and a sharp increase after 18 weeks (corresponding to glial multiplication prior to myelination). The enzyme was shown to be microsomal although freezing and thawing of whole brain tended to result in its solubilization. The apparent Km was found to be 2.5 × 10−6m and the effects of the inhibitors iminosqualene and di‐iminosqualene were studied. A comparison was made between the brain enzyme and the liver enzyme at the same age and it was seen that at 22 weeks there was a large increase in activity in the brain, prior to myelination, which was not paralleled by an increase in the activity of the liver enzyme. In this study we have measured the levels of cholesterol, desmosterol and squa‐lene‐2(3)‐epoxide‐lanosterol cyclase in whole human foctal brain, thalamus and hypothalamus, and cerebellum during early and mid‐gestation. We have also examined various properties of the cyclase enzyme and in particular the variations in its activity during early brain development.
CEREBROSIDE MAY BE FALSELY IDENTIFIED AS A SOLUBLE ‘BRAIN SPECIFIC PROTEIN’
Authors: Tremblay J. , Simon M. , Barondes S. H. 
Published: October 2006

Abstract—Injection of a soluble protein fraction from mouse brain into rabbits gave rise to an antibody which was specific for galactocerebroside. The antigen had the following characteristics: (1) it was present in the soluble fraction of a mouse brain homogenate but absent from the soluble fraction of homogenates of mouse liver, spleen, kidney and testis; (2) it was non‐dialysable; (3) it voided from a Sephadex G200 column; (4) on immunodiffusion with antibody directed against it, it gave a sharp single precipitin band; (5) it bound to DEAE cellulose column and was eluted with high salt. Given these characteristics the antigen might have been identified as a ‘brain specific protein’. However, the lipid nature of the antigen was revealed when it was found that it was not destroyed by Pronase digestion and could be quantitatively extracted with chloroform‐methanol. The antigen has been identified as a galaetocerebroside and is 100 times more abundant in the myelin fraction than in the soluble fraction of the mouse brain homogenates. The antigen could have been falsely identified as a ‘brain specific protein’ if the antigenicity and macromolecular behaviour of lipids was overlooked.