bluuebunny/crossref_metadata_2025_split huggingface dataset:
DEVELOPMENT OF AN EXPRESSION WHICH RELATES THE EXCITABLE STATE OF THE BRAIN TO THE LEVEL OF GAD ACTIVITY AND GABA CONTENT, WITH PARTICULAR REFERENCE TO THE ACTION OF HYDRAZINE AND ITS DERIVATIVES
Authors: Wood J. D. , Peesker S. J. 
Published: October 2006

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

Abstract—(1) Rats received single intraperitoneal injections of various neuroactive chemicals in order to compare the changes of gross behaviour and the level of pyridoxal phosphate as well as the activity of the decarboxylase of aromatic amino acids, of glutamate decarboxylase and of tyrosine transaminase in the brain.(2) The majority of excitatory agents tested (i.e. convulsives like amino‐oxyacetate, thiosemicarbazide, pentylenetetrazol and oxotremorine; stimulants such as amphetamine, theophylline and methylphenidate; the amphetamine‐like monoamine oxidase inhibitor tranylcypromine as well as the classical monoamine oxidase inhibitor iproniazid when combined with the monoamine releaser Ro 4‐1284) caused a decrease in aromatic decarboxylase activity which was coexistent with maximal changes of gross behaviour and partly preceded the latter. The level of pyridoxal phosphate was only partially parallel. As an exception, depression of aromatic decarboxylase was lacking after cocaine (which reduced pyridoxal phosphate only), atropine, the hallucinogens lysergic acid diethylamide and mescaline as well as the combination of the dopamine precursor l‐DOPA and the aromatic decarboxylase inhibitor Ro 4‐4602.(3) Depression of obvious central nervous functions was almost regularly accompanied and in part preceded by increase of DCA activity (i.e. with the anaesthetics pentobarbitone, diethyl ether and chloroform, the neuroleptics chlorpromazine, haloperidol, reserpine and the benzoquinolizine Ro 4‐1284 as well as the tranquillizers diazepam and chlordiazepoxide). Pyridoxal phosphate was increased during or after maximal behavioural changes by pentobarbitone and chlorpromazine only. As an exception, activation of aromatic decarboxylase was absent after morphine.(4) The activity of glutamate decarboxylase was significantly reduced by thiosemicarbazide only, whereas a distinct increase in enzyme activity was exclusively observed after atropine.(5) Tyrosine transaminase activity was significantly diminished by amino‐oxyacetate only and showed a late increase after tranylcypromine.(6) It is concluded that there is an inverse relationship, in the majority of neuroactive chemicals tested, between changes of gross behaviour and cerebral aromatic decarboxylase activity. Thereby, the latter is neither regularly related to corresponding variations of the total cerebral pyridoxal phosphate nor to hitherto described alterations of the monoamine turnover nor to effects on other vitamin B6‐dependent enzymes.
FLOW IN VIVO OF GLUCOSE CARBON TO BRAIN PROTEIN IN RATS: EFFECT OF STARVATION
Authors: Barkai A. , Mahadik S. , Rapport M. M. 
Published: October 2006

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

Abstract—

Chromatin protein fractions were separated from the nuclei from brain, liver and kidney of the guinea pig. The fractions were studied by electrophoretic methods and amino acid analysis.
Brain nuclear fractions were washed with 0.15m‐NaCl and nuclear acidic proteins then removed by 0.35 m‐NaCl. These 0.35 m‐NaCl‐extracted proteins were considered to be similar to the nuclear soluble acidic proteins.
Nonhistone‐1, histone and nonhistone‐2 fractions were obtained from 2.0 m‐NaCl‐soluble chromatin fractions by lowering the salt concentration and successive extraction with acid and alkali. The nonhistone‐3 fraction was also extracted from the nuclear residue by alkaline solution.
The contents and characteristics of the nonhistone fractions of the brain, especially the nonhistone‐1 fraction, differed among the three tissues. The histone fractions showed no obvious difference among the three tissues. The nonhistone‐1 fraction of the brain, which comprised a low percentage of total nuclear protein, contained relatively high amounts of acidic proteins.
EFFECT OF THYROID DEFICIENCY ON THE LEVELS OF SEVERAL ENZYMES IN RAT BRAIN
Authors: Bera H. , Chatterjee G. C. 
Published: October 2006

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

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

Abstract—The convulsant action of methyldithiocarbazinate (MDTC), thiocarbohydrazide (TCH) and thiosemicarbazide (TSC) has been studied in mice. The relationship between dose and time to convulsions indicated that MDTC has a dual action and is more potent than TSC. Pretreatment of mice with pyridoxal phosphate (0.25 mmol/kg) protected against convulsions and death produced by low doses of MDTC or TCH, and low or high doses of TSC. Pretreatment with pyridoxine hydrochloride (0.25 mmol/kg) protected mice against TSC but not against TCH. It protected against low doses of MDTC (0.12 mmol/kg), but shortened the latency to convulsions after intermediate doses of MDTC (0.37 mmol/kg).Glutamate decarboxylase activity (GAD, EC 4.1.1.15) in whole brain homogenates from mice killed at the onset of seizures, was significantly reduced by all 3 drugs at all doses. This inhibition did not exceed 30% after any dose of TSC or TCH, but was 64% in mice killed 4 min after the injection of MDTC (0.98 mmol/kg). The addition of pyridoxal phosphate to brain homogenates abolished GAD inhibition after MDTC but not after TCH. In vitro brain GAD was 50% inhibited by 10−4m‐MDTC, 18% by 10−4m‐TSC and 8% by 10 −4m‐TCH. Kinetic studies suggested that at low concentrations MDTC inhibits by competing with pyridoxal phosphate. At the onset of convulsions the cerebral content of pyridoxal phosphate was reduced after low or high doses of TSC (0.27 and 2.2 mmol/kg) and after high doses of MDTC (0.98 mmol/kg). All three drugs (at 10−5−10−4m) inhibited pyridoxal phosphokinase (EC 2.7.1.35) in vitro. Short latency convulsions after MDTC (0.37–0.98 mmol/kg) very probably arise from inhibition of cerebral GAD, due to competition for coenzymic sites and/or unavailability of coenzyme. Long‐latency convulsions after MDTC (0.12–0.37 mmol/kg) are comparable to those seen after TSC (0.27–2.2 mmol/kg) and may depend on a mechanism additional to inhibition of GAD.
EARLY EVENTS IN THE EFFECT OF HYDROCORTISONE ACETATE ON DNA REPLICATION IN THE RAT BRAIN
Authors: Burdman J. A. , Jahn G. A. , Szijan I. 
Published: October 2006

Abstract—Between the injection of hydrocortisone acetate to young rats and the onset of inhibition of DNA synthesis in brain, there is a lag period of 90 min. During these 90 min the only major alteration observed is a reduced formation of the DNA associated proteins while the synthesis of other brain proteins as well as that of RNA is normal. The specific activity of the enzymes thymidine kinase and DNA polymerase is also within control values.At later times, there is an inhibition in the synthesis of all brain proteins measured and of RNA and in the specific activity of the thymidine kinase. The specific activity of DNA polymerase remains normal throughout the period studied.These results indicate an important role for the DNA associated proteins in the regulation of DNA replication in rat brain.
PLASMA CHOLINE: ITS TURNOVER AND EXCHANGE WITH BRAIN CHOLINE1
Authors: Freeman J. J. , Choi R. L. , Jenden D. J. 
Published: October 2006

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

Abstract— The mechanism of the action of chlorpromazine on rat brain thiamine phosphatases were studied to clarify the properties of these enzymes in the CNS. Chlorpromazine at concentrations of 0.25‐1.0 mm caused marked decrease of microsomal and soluble thiamine triphosphatase (TTPase) activities and marked increase of microsomal thiamine diphosphatase (TDPase) activity. Imipramine and desipramine also inhibited TTPase but did not cause any marked change in TDPase activities. Addition of chlorpromazine (0.5 mm) decreased the Vmax of microsomal TTPase by about one‐half, increased that of TDPase about 3‐fold, and lowered the Km value for TDP but not for TTP.Acetone treatment of the microsomal fraction lowered the TTPase activity and markedly enhanced the TDPase activity. In acetone‐treated microsomes, chlorpromazine also inhibited TTPase activity but did not activate TDPase. Deoxycholate had similar effects to chlorpromazine on these enzyme activities.
IN VITRO STUDIES OF CEREBRAL CORTICAL RNA AND NUCLEOTIDE METABOLISM IN HYPOTHYROIDISM1
Authors: Geel S. E. , Gonzales L. K. 
Published: October 2006

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

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

Abstract—Subcellular fractions from brains of 5, 10, 13, 16, 21, 30 day‐old and adult rats were prepared. Protein content and various enzyme activities were assayed in all fractions and brain homogenates. γ‐Glutamyl transpeptidase activity and 5′‐nucleotidase were very low at 5 days of life but steadily increased, reaching adult concentrations at about 30 days after birth. Alkaline phosphatase, instead slowly decreased with maturation, while monoamine oxidase after an initial decrease, increased rapidly to adult levels.The relation between the appearance of enzymatic activity in brain and the blood‐brain barrier function is discussed.
ENZYMATIC ACTIVITY IN TUBULIN PREPARATIONS: CYCLIC‐AMP DEPENDENT PROTEIN KINASE ACTIVITY OF BRAIN MICROTUBULE PROTEIN1
Authors: Soifer D. 
Published: October 2006

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

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

Abstract—The in vivo administration of a single dose of morphine produces a decrease of tissue calcium in the rat brain. This decrease is observed to be linear, dose‐dependent, time‐dependent and to occur to an equal degree in 8 discrete brain regions. This effect of morphine is blocked by naloxone and exhibits a high degree of sterospecificity. The reserpine induced decrease of brain calcium was not antagonized by naloxone. Differentiation of this response using reserpine and naloxone indicates the possibility of calcium pools in the central nervous system.The results are discussed in terms of a specific effect of opiate drugs and the role of calcium in opiatereceptor interactions.
HIGH AFFINITY AMINO ACID TRANSPORT BY FROG SPINAL CORD SLICES
Authors: Davidoff R. A. , Adair R. 
Published: October 2006

Abstract—The characteristics of amino acid uptake by frog spinal cord slices was studied by in vitro incubations in appropriate media. The uptake mechanisms exhibited saturation; kinetic analysis demonstrated 2 distinct systems for the influx of the possible neurotransmitters: GABA, glycine, L‐glutamic acid and L‐aspartic acid. One system showed a comparatively high substrate affinity (Km values, 10‐26 μM) while the other system had a lower affinity (Km, 0.4‐1.6 mM).‐Leucine, an amino acid presumably not a transmitter, was accumulated only by a low affinity mechanism (Km 1.6 mM). The process responsible for high affinity uptake had many of the properties of an active transport mechanism. These included temperature sensitivity, energy dependence, requirement for Na+ ions and inhibition by ouabain. GABA and glycine uptake was inhibited only by closely related amino acids or structural analogues. The influx of L‐glutamic acid was competitively inhibited by the presence of L‐aspartic acid in the medium; the converse was also demonstrated. Thus, the high affinity uptake system for possible transmitter amino acids in the frog spinal cord closely resembles that described for mammalian CNS tissue. These results are compatible with the assumption that GABA, glycine, L‐glutamic acid and L‐aspartic acid are neurotransmitters in the amphibian spinal cord.
THE P2 PROTEIN OF BOVINE ROOT MYELIN: PARTIAL CHEMICAL CHARACTERIZATION1
Authors: Brostoff S. W. , Sacks H. , DiPaola C. 
Published: October 2006

Abstract—The P2 protein of bovine root myelin has chemical characteristics which differentiate it from other myelin basic proteins. The tryptic peptide map of the bovine P2 protein is distinctly different from the map of either the rabbit PI protein or the bovine CNS myelin basic protein. The tryptic peptides of the P2 protein show no overlap in either map positions or amino acid content with the peptides of the CNS myelin basic protein. Analysis of the individual peptides in the P2 map accounted for all of the amino acids present in the analysis of the whole protein. The P2 protein has a blocked NH2‐terminus, lysine at its COOH‐terminus and no hexosamine. CD studies revealed that the P2 protein has a very stable β‐structure in aqueous solution at neutral or basic pH and retains much of this structure in acid and in 8 M urea. It is suggested that these structural properties are relevant to the dual role of the P2 protein as a membrane constituent and as an antigen.
EFFECT OF DELTA‐9‐TETRAHYDROCANNABINOL ADMINISTRATION ON THE LIPID CONSTITUENTS OF RAT BRAIN SUBCELLULAR FRACTIONS
Authors: Sarkar C. , Ghosh J. J. 
Published: October 2006

Abstract—An investigation on the effects of acute (10 mg/kg) and chronic (10 mg/kg for 15 days) treatment with Δ9‐THC administration by the intraperitoneal route, on the cholesterol, cerebroside and individual phospholipid contents in microsomal, synaptosomal, mitochodrial and myelin fractions from adult rat brain, is reported. The drug has been found to affect the different subcellular membranous lipid and phospholipid components in a characteristic manner.