bluuebunny/crossref_metadata_2025_split huggingface dataset:
QUANTITATIVE HISTOCHEMICAL STUDIES OF FORMALDEHYDE‐INDUCED PARENCHYMAL FLUORESCENCE FOLLOWING L‐DOPA ADMINISTRATION
Authors: Dowson J. H. , Laszlo I. 
Published: October 2006

Abstract—A microfluorimetric method is described for quantitative histochemical study of diffuse formaldehyde‐induced fluorescence in the neuropil of various brain regions and was used to investigate the effects of L‐DOPA in the rat and cat. Regional and species differences in the effects of L‐DOPA on the CNS are reported and discussed.In the rat, suitable doses of L‐DOPA led to increases in the intensity of fluorescence in the neuropil of the samples of caudate nucleus, which were greater than the increases in the neuropil of the other regions studied. Marked increases in the intensity of fluorescence in the neuropil of the cat brain samples were produced by doses of L‐DOPA/kg body wt. which were too low to produce detectable increases in the fluorescence of the rat brain samples.
RELEASE OF AROMATIC AMINES FROM BRAIN TISSUES OF THE RAT IN VITRO1
Authors: Baldessarini R. J. 
Published: October 2006

Abstract—Radioactive β‐hydroxylated phenylethylamines, DL‐octopamine and DL‐metara‐minol, as well as DL‐norepinephrine, were released from slices or minces of rat brain in vitro by electrical or ionic depolarizing stimuli. In contrast, labelled D‐amphetamine and p‐tyramine were poorly released and the release of urea was barely perceptible. Addition of unlabelled L‐norepinephrine to an incubating medium led to displacement of previously bound [3H]octopamine and [3H]metaraminol from a synaptosomal preparation. Pretreat‐ment of rats with intrathecal 6‐hydroxydopamine markedly decreased the ability of slices of their brains to release [3H]norepinephrine and [3H]octopamine. We suggest that certain phenolic β‐hydroxylated phenylethylamines may enter central, norepinephrine‐containing nerveendings, may be stored in presynaptic vesicles and may be released by nerve stimulation. Under certain circumstances such compounds may act as neurotransmitters with unknown post‐synaptic effects.
STUDIES ON THE ORIGIN OF PYRIMIDINES FOR BIOSYNTHESIS OF NEURAL RNA IN THE RAT
Authors: Hogans Alice F. , Guroff G. , Udenfriend S. 
Published: October 2006

AbstractUridine was far superior to orotic acid in labelling the RNA in incubated slices of rat brain. On the other hand, uridine and orotic acid were equally effective in labelling the RNA of hepatic or renal slices In rats in vivo, uridine, but not orotic acid, labelled brain RNA, and the cerebellar RNA contained the most label. In contrast, both uridine and orotic acid labelled hepatic RNA. Only when surgical intervention prevented peripheral metabolism of orotic acid, thereby raising its concentration in the plasma, did neural tissue utilize this precursor for limited biosynthesis of RNA. However, among the tissues studied, the preference for uridine over orotic acid for RNA synthesis was unique to neural tissue.
CORTICOSTERONE BINDING BY RAT BRAIN CYTOSOL1
Authors: Grosser B. I. , Stevens W. , Bruenger F. W. , Reed D. J. 
Published: October 2006

AbstractSignificant quantities of corticosterone were associated with macromolecules of the brain cytosol following intrathecal administration of [3H]corticosterone to adrenalectomized rats. Fifteen times more steroid was found associated with proteins from adrenalectomized rats than from control animals or adrenalectomized animals pretreated with corticosterone. Pretreatment of adrenalectomized rats with 11‐dehydrocorticosterone, Cortisol and cortisone decreased the amount of [3H]corticosterone found associated with protein, whereas progesterone, oestradiol and testosterone did not interfere with the association of [3H]corticosterone with macromolecules of the cytosol. Further evidence for protein‐steroid interaction was obtained by incubating [3H]corticosterone (B), [3H]cortisol (F), or 11‐[3H]deoxycortisol (S) with brain cytosols. The degree of binding was in the order B > F > S.
THE INFLUENCE OF INTRAVENTRICULARLY INJECTED AMINO ACID EXCITANTS ON THE LABELLING OF ENDOGENOUS BRAIN AMINO ACIDS FROM [U‐14C]ACETATE IN NEMBUTALIZED MICE
Authors: Watkins J. C. 
Published: October 2006

AbstractMice were anaesthetized with nembutal and the effects of intraventricularly injected excitant amino acids on [U‐14C]acetate metabolism were investigated. The natural excitant amino acids, l‐glutamate and l‐aspartate, reduced the incorporation of 14C from [U‐14C]acetate into glutamine, GAB A and possibly alanine. The synthetic excitant amino acid, N‐methyl‐d‐aspartate caused a reduction in the incorporation of 14C from intraventricularly injected [U‐14C]acetate into all of the brain amino acids labelled by [U‐14C]acetate within 5 min. It is suggested that these effects may be due to changes in pool sizes of tricarboxylic cycle intermediates, to inhibition of acetyl‐CoA formation, or both. Differences in the metabolic effects of the synthetic and natural excitants are interpreted in terms of the uptake of the natural amino acids into glutamine‐forming pool(s) of glutamate metabolism.
EFFECT OF HAEMORRHAGE ON THE RAPID AXONAL TRANSPORT OF NEUROHYPOPHYSIAL PROTEINS OF THE RAT
Authors: Norströ A. , Sjöstrand J. 
Published: October 2006

AbstractFollowing injection of [35S]cysteine into the region of the supraoptic nucleus male rats were subjected to haemorrhage and the radioactivity of the supraoptic nucleus and neurohypophysial proteins was measured at various time intervals after injection. Following haemorrhage the incorporation of [35S]cysteine into supraoptic nucleus proteins increased. Evidence was obtained for a lag period of 1 to 2 h for the supraoptic nucleus proteins to become available for axonal transport. As judged from the time of arrival of labelled material in the neurohypophysis, haemorrhage did not change the rapid rate of axonal transport (190 mm/day). At 15 min following bleeding, the radioactivity in fraction A (a neurophysin) of the neurohypophysis was reduced, which indicated a release of this rapidly transported protein. During the following 15 min an increase in the protein‐bound radioactivity of the neural lobe occurred which exceeded that in controls. This is taken as evidence for increased axonal transport in response to haemorrhage.
AGE‐DEPENDENT VARIATIONS OF THE HUMAN N‐ACETYL‐β‐D‐HEXOSAMINIDASES
Authors: Harzer K. , Sandhoff K. 
Published: October 2006

AbstractThe total N‐acetyl‐β‐d‐hexosaminidase (hexosaminidase A plus B) activity of the human brain increases during life until the age of 70 years to about twice the activity found in the foetal brain. This activity roughly parallels the increasing level of brain ganglio‐sides. Simultaneously, the ratio between the hexosaminidases A and B changes from approx. 3.4 to 1.1 as established by the microscale isoelectric focussing of the enzymes from crude extracts. Age‐dependent variations can be also demonstrated for other glycosidase activities: The β‐d‐glucosidase is shown to increase, the α‐d‐mannosidase and α‐l‐fucosidase to decrease during life. The enzyme values are related to the protein content, the age‐dependent shift of which we have determined in the human brain. In different organs and body liquids distinct differences are found for the levels of the total hexosaminidase activity as well as for the hexosaminidase pattern. The relation of the hexosaminidase activity to the ganglioside degradation during the human development is discussed.
DEVELOPMENT OF THE UPTAKE AND STORAGE OF L‐[3H]NOREPINEPHRINE IN THE RAT BRAIN
Authors: Coyle J. T. , Axelrod J. 
Published: October 2006

AbstractThe uptake and storage of L‐[3H]norepinephrine at various stages of development was examined in homogenates of rat brain. For the adult animal, active uptake accounted for 80 per cent of the total uptake. At 14 days of gestation, no active uptake was demonstrable At 18 days of gestation, saturable uptake of L‐[3H]norepinephrine with a Km of 3 × 10 −7m was first demonstrable; the Km value did not vary during subsequent development. The Vmax. of uptake increased five‐fold between 18 days of gestation and 28 days postnatally, at which stage it was the same as the adult value. The development of saturable uptake paralleled but preceded the increase in endogenous norepinephrine. When homogenates were incubated with l‐[3H]norepinephrine and subjected to centrifugation on linear sucrose gradients, there was a peak of tritium in the synaptosomal fractions; the magnitude of the peak increased with maturation of the brain. The increase in the peak of tritium paralleled the increase in particulate LDH activity and was distinct from the peak of MAO activity. Desipramine, a compound that blocks the initial uptake of norepinephrine, first exhibited inhibition of uptake at 19 days of gestation; the degree of inhibition did not vary during subsequent development. In contrast, reserpine, a compound which inhibits the intra‐neuronal storage of norepinephrine, exhibited a progressive increase of inhibition with maturation of the brain at and subsequent to 19 days of gestation.
EFFLUX OF ENDOGENOUS PROTEIN FROM NON‐MYELINATED OLFACTORY NERVE AS MONITORED BY TRYPTOPHAN FLUORESCENCE
Authors: Hines J. F. , Easton D. M. 
Published: October 2006

AbstractEndogenous protein was lost from the olfactory nerve of the garfish (Lepisosteus osseus) when the excised but excitable nerve was bathed with normal physiological solution. The protein could be detected by its fluorescence at 340 nm when excited at 280 nm. The relative concentrations were expressed in terms of an equivalent fluorescence from a standard solution of tryptophan. From an initial fluorescence, equivalent to 5 × 10−10 mol of tryptophan/mg of nerve washed out during each 10 min, the efflux may decline slowly in rate to 10−11 mol/mg per 10 min. Depolarizing direct current or a several‐fold increase of the concentration of KCl in the bathing solution might transiently double the rate of efflux above the resting rate during continuous monitoring of the fluorescence intensity. Changes in concentrations of external KCl, glucose or sucrose, in ionic strength (at constant osmolality), or in osmolality all produced a transient increase of fluorescence in the effluent from the nerve. An increase followed both introduction of the experimental solution and the return to the control solution. We interpreted the increase in intensity of fluorescence of the washout solution to indicate an increase in concentration of an intrinsic specific protein washed from the nerve. By electrophoresis, a single acidic fluorescent protein band was observed travelling with the marking dye. Chromatographic fractionation on Sephadex suggested a mol. wt. in excess of 100,000.
ISOLATION AND ELECTROPHORETIC IDENTIFICATION OF HISTONES OF RAT BRAIN AND LIVER
Authors: Duerre J. A. , Gaitonde M. K. 
Published: October 2006

Abstract—

Relatively pure brain nuclei were prepared on a discontinuous sucrose gradient which gave yields of between 40 and 60 per cent.
An extraction procedure has been developed for the isolation of total histones from brain and liver nuclei. This procedure is also applicable to the isolation of histones directly from whole brain and liver.
The electrophoretic pattern of histones prepared from brain and liver by the above procedure was similar to that of calf thymus histones.
UPTAKE AND METABOLISM OF [3H]NOREPINEPHRINE IN THE CEREBRAL HEMISPHERES OF CHICK EMBRYOS1,2
Authors: Kellogg C. , Vernadakis A. , Rutledge C. O. 
Published: October 2006

Abstract— The uptake and metabolism of [3H]norepinephrine were studied in slices of cerebral hemispheres removed from chick embryos at 10, 15 and 20 days of embryonic age, as well as from 90‐day‐old hens. Brain tissue from all age groups concentrated [3H]norepinephrine to much greater levels at 37°C than at 0°C. There was a marked increase in the rate of accumulation of [3H]norepinephrine in tissues from 10 to 15 days of embryonic age, with no further increase in the rate observed from 15 to 20 days of embryonic age.Tissue slices were incubated for 20 min with [3H]norepinephrine, and the deaminated metabolites of norepinephrine were separated by paper chromatography. In tissues from all age groups, the neutral metabolites were produced in greater amounts than the acid metabolites. A significant increase in the amounts of deaminated metabolites formed was observed in the period from 10 to 15 days of embryonic age and a significant decrease in the amounts formed was observed in the period from 15 to 20 days of embryonic age. The deamination at 20 days was very similar to that observed in the adult.A significant decrease in the level of the deaminated metabolites was noted in all age groups in response to cocaine (an inhibitor of neuronal uptake mechanisms), an observation suggesting that mechanisms for neuronal uptake of NE are functional by 10 days of embryonic development in the chick. However, a significant increase in the level of deaminated metabolites in response to reserpine (an inhibitor of uptake of NE into storage granules) was observed only in slices taken from 20‐day embryos and from the 90‐day‐old hen. The effect in the hen was more prominent than in the 20‐day embryo. These results were interpreted to indicate that mechanisms for the uptake of NE develop at an earlier embryonic age than mechanisms for the storage of NE and that mechanisms for storage continue to develop after hatching.
PROTEIN SYNTHESIS IN VITRO IN NUCLEI OF HUMAN NERVOUS TISSUE
Authors: Haglid K. G. 
Published: October 2006

Abstract—

In vitro incorporation of tritiated leucine into nuclear proteins of normal human brain, astrocytoma I and II and glioblastoma multiforme was investigated. The distribution of radioactivity among various protein fractions of nuclei was determined.
The results demonstrate that the isolated nuclei of astrocytoma I and II incorporate radioactivity into proteins at least 40 times more actively than nuclei of normal human brain or glioblastoma multiforme.
The residual protein fraction was the most highly labelled fraction among the nuclear pioteins. This fraction from astrocytomas incorporates relatively more radioactivity than the similar fraction of normal human brain or glioblastoma multiforme. The buffered‐saline soluble protein fraction of astrocytoma nuclei contained a relatively lower amount of radioactivity than the similar fraction of normal human brain or glioblastoma multiforme. The total radioactivity incorporated into the deoxyribonucleoproteins seemed to increase with the malignancy of the tissue investigated. The significance of the results with respect to malignant transformation is discussed.
THE EFFECT OF DIETHYL‐α‐FLUOROGLUTARATE ON PHOSPHATES AND GLUTAMATE IN SLICES OF RABBIT CEREBRAL CORTEX1
Authors: Cohen H. P. , Lin S. 
Published: October 2006

Abstract— The diethyl ester of α‐fluoroglutarate (DEFG), an inhibitor of glutamate dehydrogenase, was prepared, and its effect on glutamate and phosphates in slices of rabbit cerebral cortex was examined. The primary effect of the drug on cortical slices incubating in a Krebs‐Ringer glucose medium was to decrease the tissue levels of glutamate in association with decreased levels and turnover of high‐energy phosphates. Assimilation of exogenous glutamate by the slices was partially blocked in the presence of the drug and severely depressed oxidative phosphorylation resulted when glutamate and DEFG were both present in the incubation mixture. The results suggested a significant relationship between the activity of cerebral glutamate dehydrogenase and oxidative phosphorylation.During incubation in a Krebs‐Ringer glucose medium the endogenous pool of free amino acids in the cortical slice partitioned with the medium. Little or no glutamate, aspartate or GABA was present in the medium after incubation, but glycine, alanine, threonine, serine and glutamine did partition to varying degrees, with over one‐half of the glutamine present in the incubation medium. With the exception of ‘leakage’ of aspartate, the partitioning patterns were relatively unaffected by the presence of added glutamate or DEFG.
THE LIMITED PROTEOLYSIS OF BOVINE NEUROPHYSINS BY CATHEPSIN D
Authors: Pickup J. C. , Hope D. B. 
Published: October 2006

Abstract— The limited proteolysis of the bovine neurophysins at acid pH has been studied and the enzyme responsible has been characterized. Only 15 per cent of the catheptic activity in 4‐year‐old acetone‐dried posterior pituitary lobe powder is soluble at pH 4.0. Solubility increases as the age of the powder decreases and the cathepsin is completely soluble in the presence of 1% Triton X‐100. Acid proteinase activity in the neurohypophysis is not thiol activated and is inhibited by 3‐phenylpyruvic acid. Bovine serum albumin was degraded at only 1 per cent of the rate of haemoglobin but with the same pH optimum (3.7). On this basis the enzyme was identified as cathepsin D.Neurophysin‐I is degraded in two stages by cathepsin D; the first product (neurophysin‐I′) runs faster and the second product (neurophysin‐I″) runs slower than the native protein on starch‐gel electrophoresis at pH 8.1. Neurophysin‐II is also degraded in two stages; the first product has a higher electrophoretic mobility than the native protein and is identical in mobility with the faster‐running component of the so‐called neurophysin‐M of Hollenberg and Hope (1967b). Prolonged incubation with the cathepsin gives rise to a slower‐running component. Neurophysin‐C is not attacked by the acid proteinase. Neurophysin‐I′ and I″ have been isolated by ion‐exchange chromotography. They have the same N‐terminal amino acid (alanine) and C‐terminal sequence (Ala‐Phe‐Ser) as the native protein and both bind 8‐argininevasopressin. Neurophysin‐I′ is identical in amino acid composition with the native protein but neurophysin‐I″ has lost one leucine and two aspartic acid residues.Reduction, 14C‐alkylation and separation of the fragments by starch‐gel electrophoresis shows that the structural and functional integrity of neurophysin‐I″ is maintained by the disulphide bonds, even though a tripeptide has been split out of the interior of the molecule. The low molecular weight material produced by catheptic digestion of neurophysin‐I has been purified and shown to have a composition of one leucine and two aspartic acid residues. It is suggested that extensive in vivo proteolysis of neurophysin by lysosomal cathepsin, with consequent abolition of hormone‐binding ability, is unlikely.
THE PREPARATION OF CHOLINERGIC SYNAPTOSOMES FROM BOVINE SUPERIOR CERVICAL GANGLIA
Authors: Wilson W. S. , Cooper J. R. 
Published: October 2006

Abstract—A method is described for the preparation of relatively pure cholinergic synaptosomes from bovine cervical sympathetic ganglia. After dispersion of the tissue by incubation with collagenase, differential centrifugation yielded a crude synaptosomal fraction (P2), which was further purified by centrifugation on sucrose or Ficoll‐sucrose density gradients. Assay of acetylcholine and choline acetyltransferase, and electron microscopy confirmed that presynaptic nerve endings survived the incubation procedure, appeared in the P2 fraction and thereafter sedimented to a density of approx. 1.13 in sucrose and 1.06 in Ficoll‐sucrose. The washed P2 fraction had an acetylcholine content of 2.3 nmol/mg of protein, which is at least three times higher than the corresponding fraction from brain.
SUBCELLULAR DISTRIBUTION OF POTASSIUM, SODIUM, MAGNESIUM, CALCIUM AND CHLORIDE IN CEREBRAL CORTEX1
Authors: Hanig Ruth C. , Tachiki K. H. , Aprison M. H. 
Published: October 2006

AbstractThe subcellular distributions of potassium, sodium, magnesium, calcium and chloride have been determined for rabbit cerebral cortex. After homogenization and differential centrifugation, the following percentages of ions were associated with the particulate fraction (nuclear, mitochondrial, synaptic vesicles, and microsomal): (a) 19% of the total potassium; (b) 22% of the total sodium; (c) 77% of the total calcium; (d) 69% of the total magnesium; and (e) less than 2% of the total chloride. However, the sum of the potassium and sodium content in each of the particulate fractions was greater than the sum of the calcium and magnesium content. After hypo‐osmotic shock of the crude mitochondrial fraction (MT), more sodium than potassium (μmol/g wet wt.) was associated with the mitochondrial (M1) and synaptic vesicle (M2) fractions. The molar ratio of sodium to potassium was 1·4 for M1 and 4·5 for M2. The association of 22Na+ with the particulate fractions was further studied by the method of equilibrium dialysis. The data from both types of experiments indicate that a large fraction of the sodium in cortical tissue appears to be in a bound state.
INCREASE OF BRAIN TRYPTOPHAN BY ELECTROCONVULSIVE SHOCK IN RATS
Authors: Tagliamonte A. , Tagliamonte P. , Chiara G. Di , Gessa R. , Gessa G. L. 
Published: October 2006

Abstract—ECS markedly increased tryptophan and 5‐hydroxyindoleacetic acid levels in brain. Brain serotonin and plasma tryptophan levels were unaffected.
OCCURRENCE AND DISTRIBUTION OF AROMATIC l‐AMINO ACID (l‐DOPA) DECARBOXYLASE IN THE HUMAN BRAIN
Authors: Lloyd K. G. , Hornykiewicz O. 
Published: October 2006

Abstract—The enzymatic decarboxylation of l‐DOPA was measured in isotonic dextrose homogenates of different regions of the human brain by estimating 14CO2 evolved from tracer amounts of d l‐DOPA[carboxy1‐14C]. Enzyme activity was linear with respect to tissue concentration and time of incubation. The reaction exhibited a pH maximum at 7·0, was completely dependent upon the presence of high concentrations of pyridoxal phosphate, proceeded at the same rate in an atmosphere of air and nitrogen, and produced dopamine in addition to CO2 as a reaction product. The enzyme preparation behaved like an aromatic l‐amino acid decarboxylase: it also decarboxylated o‐tyrosine and when incubated with 5‐hydroxytryptophan, serotonin was isolated as the reaction product; but it was devoid of activity towards d‐DOPA[carboxy1‐14C]. Within the human brain, l‐DOPA decarboxylase was most active in the putamen and caudate nucleus; the pineal gland, hypothalamus, and the reticular formation and dorsal raphe areas of the mesencephalon exhibited considerable activity. Areas of cerebral cortex exhibited very low enzymatic activity and in regions composed predominantly of white matter, l‐DOPA decarboxylase activity was not significantly above blank values. The activity of l‐DOPA decarboxylase in the human putamen and caudate nucleus tended to decrease with the age of the patients; in comparatively young subjects (46 yr old) the enzyme activity compared favourably with that found, by means of the same assay technique, in the caudate nucleus of the cat.
THE ROLE OF NERVE GROWTH FACTOR IN THE RAMIFICATION OF SYMPATHETIC NERVE FIBRES INTO THE RAT IRIS IN ORGAN CULTURE
Authors: Johnson D. G. , Silberstein S. D. , Hanbauer I. , Kopin I. J. 
Published: October 2006

AbstractSmall amounts of nerve growth factor (NGF) were present in the superior cervical ganglion and the iris of the rat. The observations that NGF content in each of the tissues was depleted during organ culture and that more NGF appeared in the media than was originally present in the tissues indicated that synthesis or activation of NGF had occurred in organ culture. Antibody to NGF or the depletion of endogenous NGF retarded growth of new sympathetic axons into irides in organ culture. Exogenously added NGF appeared to enhance the initiation of axonal sprouting and the rate of the ramification of nerve fibres.