bluuebunny/crossref_metadata_2025_split huggingface dataset:
REGIONAL DISTRIBUTION OF PUTRESCINE, SPERMIDINE AND SPERMINE IN RELATION TO THE DISTRIBUTION OF RNA AND DNA IN THE RAT NERVOUS SYSTEM
Authors: Seiler N. , Schmidt‐Glenewinkel T. 
Published: October 2006

Abstract—Putrescine, spermidine, spermine, RNA, DNA and protein concentrations were determined in 14 parts of the rat nervous system. If the concentrations are expressed in DNA units, putrescine and spermidine concentrations change concomitantly in the different brain parts, with the exception of hypothalamus, where relatively higher putrescine than spermidine concentrations are observed. The constancy of putrescine/spermidine ratios indicates the value of putrescine concentration as an index of spermidine biosynthesis. Spermidine correlates with RNA, except in medulla, spinal cord and peripheral nerves. It is assumed that the relative excess of spermidine in these structures indicates an additional functional role. Spermine/DNA ratios are remarkably constant in the diencephalic and telencephalic regions; they are also nearly constant, but significantly lower in midbrain, medulla, spinal cord and cerebellum. This observation gives additional support for the preferential interrelation of spermidine with RNA and spermine with DNA; i.e. for different functional roles of these two narrowly related polycations.
A RADIOIMMUNOASSAY FOR MYELIN BASIC PROTEIN AND ITS USE FOR QUANTITATIVE MEASUREMENTS
Authors: Cohen S. R. , McKhann G. M. , Guarnieri M. 
Published: October 2006

Abstract—A specific radioimmunoassay (RIA) for myelin basic protein is described which is sensitive to 10−9 g of basic protein. The amount of basic protein detected in isolated myelin by the RIA and by SDS‐gel electrophoresis and spectrophotometric quantitation agree to within experimental error. In contrast to isolated myelin, the major portion of the basic protein in fresh tissue is not accessible to its antibody. It is shielded from its antibody in a complex which is disrupted by heat, organic solvents, and various detergents. Maximum antibody binding was obtained with tissue heated to 100°C for 10 min. It is possible to calculate that the RIA quantitatively detects basic protein in boiled tissue. Boiled adult rat brain contains approximately 2·5 μg of basic protein/mg wet wt of cerebral cortex. The antibody to basic protein has no capacity to bind non‐neural tissues.
THE FORMATION OF CDP‐DIGLYCERIDE BY ISOLATED NEURONAL NUCLEI
Authors: Thompson R. J. 
Published: October 2006

Abstract—A population of neuronal nuclei isolated from the rabbit cerebral cortex actively incorporates cytidine‐5′‐triphosphate into an acid‐insoluble product, the incorporation is stimulated by magnesium or manganese ions and appears to utilize CTP directly as substrate. Other nucleoside triphosphates stimulate CTP incorporation at low substrate concentrations, apparently by preventing CTP breakdown, while higher concentrations of nucleoside triphosphates strongly inhibit CTP incorporation at either low or saturating substrate concentrations. CTP incorporation appears to be unrelated to RNA synthesis in that it exhibits a different pH and divalent cation optimum, is unaffected by inhibitors of RNA synthesis, and is strongly inhibited by low concentrations of detergent but not by preincubation of nuclei at 37°C. The product of CTP incorporation is almost entirely soluble in acidified lipid solvents and is not sensitive to digestion by RNAase under conditions where the enzyme can digest newly synthesized RNA. CTP incorporation is markedly stimulated by phosphatidic acid, the stimulated incorporation showing the same characteristics as the unstimulated incorporation, and is inhibited by inositol. Alkaline hydrolysis of the product releases the great majority of radioactivity as 5′‐CMP as judged by chromatography and by 5′‐nucleotidase action. The product of CTP incorporation migrates with synthetic CDP‐diglyceride in five solvent systems. It is concluded that under optimal conditions for CTP incorporation, less than 5% of the incorporated CTP can be included in a polynucleotide chain, this small proportion of the total incorporation could either represent residual RNA synthesis or the formation of poly (C) with an average chain length of less than 3 residues. Under optimal conditions the great majority of CTP incorporation by neuronal nuclei in the presence of either magnesium or manganese ions represents the formation of the unique liponucleotide CDP‐diglyceride.
INHIBITION OF 5′‐NUCLEOTIDASE IN RAT BRAIN BY METHYLXANTHINES
Authors: Tsuzuki Junji , Newburgh R. W. 
Published: October 2006

Abstract—Rat brain 5′‐nucleotidase (EC 3.1.3.5) is inhibited by methylxanthines such as theophylline. Inhibition of the 5′‐nucleotidase by theophylline appears more efficient than the inhibition of cAMP phosphodiesterase by this drug. A similar inhibition is observed with caffeine, theobromine, 7′‐methyl‐xanthine and 1‐methylxanthine.
CIS‐ AND TRANS‐4‐AMINOCROTONIC ACID AS GABA ANALOGUES OF RESTRICTED CONFORMATION
Authors: Johnston G. A. R. , Curtis D. R. , Beart P. M. , Game C. J. A. , Mcculloch R. M. , Twitchin B. 
Published: October 2006

Abstract— Cis‐4‐aminocrotonic acid, an analogue of GABA in a folded conformation, appears not to act as a GABA analogue with respect to bicuculline‐sensitive postsynaptic receptors, ‘high affinity’ GABA uptake and GABA: 2‐oxoglutarate aminotransferase in the mammalian central nervous system. On the other hand, trans‐4‐aminocrotonic acid, an analogue of GABA in an extended conformation, acts as efficiently as GABA with respect to each of the above systems, indicating that extended rather than folded conformations of GABA are likely to be important in the interaction of GABA with the specific macromolecules concerned.
MOLECULAR FORMS OF ACETYLCHOLINESTERASE: THEIR DE NOVO SYNTHESIS IN MOUSE NEUROBLASTOMA CELLS
Authors: Rieger F. , Faivre‐Bauman Annie , Benda P. , Vigny M. 
Published: October 2006

Abstract—Rat mouse AChE molecular forms are indistinguishable with respect to their sedimentation coefficients and their evolutive proportions during brain maturation. Among rat or mouse erythrocytes, rat C6 glial cells, and mouse 2A and NS 20 neuroblastoma cells, only neuroblastoma cells showed both the ES and HS molecular forms with a 1:1 proportion for NS 20 cells. All these cells lack a third molecular form (16S), which is present in rat and mouse superior cervical ganglia. After irreversible inhibition of pre‐existing NS 20 neuroblastoma AchE, the ES form is first synthesized (de novo synthesis). The HS form begins to appear after a lag time of several hours and represents, 24 h after inhibition, only 15% of the total recovered activity, which is near the initial level. The initial relative proportions return by 2 to 3 days after inhibition. The recovery of the HS form is, for the most part, blocked by actinomycin D, which does not block the recovery of activity itself, which remains as an ES form.It seems that integration of the ES form into the HS form more probably depends on the synthesis of a new messenger RNA, which is required for the synthesis of either new AChE polypeptide chain, polymerization initiating protein or activating enzyme.
PROPERTIES OF TYROSINE HYDROXYLATION IN LIVING MOUSE NEUROBLASTOMA CLONE N1E‐115
Authors: Richelson E. 
Published: October 2006

Abstract—Tyrosine hydroxylation was studied in intact cells of mouse neuroblastoma clone N1E‐115 which have high levels of tyrosine 3‐monooxygenase (EC 1.14.16.2) and which have been fully characterized for tyrosine transport. Measurement of [3H]OH formed from L‐[3.5‐3H]tyrosine in the medium was the method of assay and [3H]OH formed was stoichiometric with the formation of L‐[3H]3.4‐dihydroxyphenylalanine. Tyrosine hydroxylation was dependent on time of incubation, cell number, and the concentration of [3H]tyrosine in the medium. From velocity vs. [3H]tyrosine concentration experiments. two apparent Km, values were obtained: Km1= 10 ± 2μM: Km2= 140 ± 10μM. Substrate inhibition occurred with tyrosine concentrations between 20 and 50 μM. The reaction was twice as fast at pH 5.5 as at pH 7.4. α,α′‐Dipyridyl (1 mM) caused major inhibition (75%) when [3H]tyrosine concentration was 10 μM. L‐3‐Iodotyrosine was a competitive inhibitor with Ki= 0.3 μM. Dopamine was a non‐competitive inhibitor with Ki= 500 μM. 1‐Norepinephrine had no effect. These results show that the hydroxylation of tyrosine by living N1E‐115 cells has many of the properties of the reaction catalyzed by purified tyrosine 3‐monooxygenase from normal tissue.
CATECHOL‐O‐METHYLTRANSFERASE IN RAT ERYTHROCYTE AND THREE OTHER TISSUES: COMPARISON OF BIOCHEMICAL PROPERTIES AFTER REMOVAL OF INHIBITORY CALCIUM1
Authors: Quiram D. R. , Weinshilboum R. M. 
Published: October 2006

Abstract—The biochemical characteristics of soluble catechol‐O‐methyltransferase (COMT) activity in rat erythrocytes were compared with the properties of the soluble enzyme in rat liver, heart, and brain. COMT was measured by a procedure that avoided artifacts of some other assay procedures including inhibition of the enzyme by endogenous calcium. After the removal of calcium from the reaction mixture the apparent Michaelis‐Menten constants for the two cosubstrates of the COMT reaction, S‐adenosyl‐1‐methionine (SAM) and 3,4‐dihydroxybenzoic acid (DBA), were similar in tissue preparations of rat liver, brain, heart and blood. The apparent Km, values for the four tissues ranged from 5.7 to 6.7 × 10−6M and from 0.9−1.4 × 10−4M for SAM and DBA, respectively. The optimal pH and the optimal concentration of magnesium for the assay of red blood cell COMT were also similar to those for the enzyme in the three other rat tissues. After the removal of endogenous calcium, COMT activity in all four tissues was inhibited by the addition of calcium, and the [CaCl2] necessary to inhibit the enzyme activity 50% was 3−5 × 10−4M in all cases. The relative activities of COMT in the rat heart, brain, erythrocyte, and liver when expressed per g tissue or per ml of packed red blood cells were 1 to 1.15 to 1.58 to 140, respectively.
THE PHOSPHORYLATION OF BRAIN MICROTUBULAR PROTEINS IN SITU AND IN VITRO
Authors: Reddington M. , Tan L. P. , Lagnado J. R. 
Published: October 2006

Abstract—The phosphorylation of microtubular proteins isolated by reassembly in vitro from slices of guinea‐pig cerebral cortex labelled with [32P]orthophosphate was investigated. Under the conditions tested, both and the α and β forms of tubulin contained metabolically‐active P which accounted for about one third of the total 32P incorporated into protein; the remaining protein‐bound 32P was associated with 3–4 minor high MW components co‐purifying with tubulin during two cycles of assembly4sassembly. Microtubular protein prepared in this way contained approx. 0.8 mol of alkali‐labile P/mol of tubulin dimer (M.W. 110,000). In vitro studies showed that reassembled microtubular protein preparations catalysed the incorporation of up to 0.55 mol of P/mol of tubulin dimer during incubation with Mg2+ and [γ32P]ATP. The reaction was linear during the first 30 min of incubation at 37°C. Cyclic AMP (10 μm, final concentration) caused a transient increase in the initial rates of tubulin phosphorylation. Little label was incorporated into the minor high M.W. components under these conditions. The in vitro phosphorylation of microtubular protein increased in a non‐linear manner with respect to protein concentration: this was in contrast to earlier experiments showing linear kinetics when chromatographically isolated tubulin was tested for intrinsic kinase activity. Isolated microtubular protein preparations bound [3H]GTP, [3H]ATP and to a lesser extent, [3H]cyclic AMP, and exhibited Ca2+‐ATPase activity (up to 60pmol Pi released min/mg protein at 37°C).
SUBCELLULAR DISTRIBUTION OF TAURINE AND CYSTEINE SULPHINATE DECARBOXYLASE ACTIVITY IN OX RETINA
Authors: Macaione S. , Tucci G. , Luca G. De , Di Giorgio R. M. 
Published: October 2006

Abstract– Taurine levels have been determined in primary and secondary subcellular fractions of ox retina and pigment epithelium.About the 79.5% of recovered taurine is located in the soluble fraction (S3), while the remainder is associated with the particulate components. In the secondary subcellular fractions, taurine is primarily associated with the synaptosomal fraction.Cysteine sulphinate decarboxylase is predominantly associated with particulate components of retinal cells. About the 50% of the recovered enzyme activity of crude mitochondria is present in the synaptosomal fraction.
HETEROGENEITY OF ACETYLCHOLINESTERASE IN NEUROBLASTOMA
Authors: Chang C.‐H. , Blume A. J. 
Published: October 2006

Abstract– Multiple forms of acetylcholine hydrolyzing activity have been observed in Triton X‐100 treated homogenates of mouse neuroblastoma cells. All these forms appear to be the true acetylcholinesterase, AChE (EC 3.1.17): they are substrate‐inhibited; hydrolyze acetylcholine > acetyl‐β‐methylcholine ≫ butrylcholine and are preferentially inhibited by specific AChE inhibitors. Almost all of the cell AChE activity is membrane associated, but readily ‘solubilized’ by Triton X‐100 and as such appears free of membrane contamination. With the aid of affinity chromatography the ‘solubilized’ neuroblastoma AChE has been partially purified (490‐fold) to a specific activity of 34,300 nmol/min/mg protein.Four active neuroblastoma AChE species appear upon acrylamide gel electrophoresis (with MWs of 64,000; 116,000; 186,000 and 284,000) while three species (4S, 6S and 9.6S) have been found upon sucrose gradient sedimentation analysis. We have determined that the 4S form migrates on acrylamide as the 116,000 MW species and the 9.6S form contains, in equal amounts, the 186,000 and 284,000 MW acrylamide species. Numerous active AChE forms are seen on Sepharose 6B chromatography. From comparing the crude, 4S, 9.6S and partially purified AChEs on acrylamide gels, sucrose gradients and Sepharose, mouse neuroblastoma appears to contain active AChE units which are capable of multiple types of dissociation and reassociation. An attempt is made to correlate all the observed AChE forms as well as relate this data to that known about AChE obtained from other sources.
RELEASE OF GLUTAMATE AND OTHER AMINO ACIDS FROM ARTHROPOD NERVE–MUSCLE PREPARATIONS
Authors: DAOUD A. , Miller R. 
Published: October 2006

Abstract—A study has been made of the release of glutamate and other amino acids from perfused leg preparations from Carcinus and Schistocerca, at rest and during stimulation of motor nerves to the leg muscles. Stimulation caused an increase in release af many amino acids. No evidence was obtained to link glutamate release from such preparations with synaptic function. If release of transmitter glutamate is to be demonstrated in arthropods, techniques must be devised to avoid contamination with large quantities of non‐transmitter glutamate.
BINDING OF [3H]KAINIC ACID, AN ANALOGUE OF l‐GLUTAMATE, TO BRAIN MEMBRANES
Authors: Simon J. R. , Contrera J. F. , Kuhar M. J. 
Published: October 2006

Abstract—The specific binding of [3H]kainic acid to synaptic membranes from rat brain was saturable with a dissociation constant of about 60 nm. The apparent maximal number of binding sites was about 1 pmol/mg protein. The most effective displacer of specific [3H]kainic acid binding was quisqualic acid, a powerful excitant which is structurally similar to l‐glutamate. However, quisqualic acid was one‐third as potent a displacer as kainic acid itself. l‐Glutamate was the next potent in displacing [3H]kainic acid binding, but also was less effective (1/25) than kainic acid itself. All other compounds including suspected neurotransmitters were at least an order of magnitude lower in potency compared to l‐glutamate. When various tissues and brain regions were tested for specific [3H]kainic acid binding, we found the specified binding was localized to grey matter in the brain. In studies of subcellular fractionation of the brain, we found that crude synaptosomal membrane preparations were most enriched in specific [3H]kainic acid binding. Specific [3H]kainic acid binding in various regions of the rat brain varied 5‐ to 6‐fold.
CYTOCHROME REDOX POTENTIAL DEPENDENCE ON SUBSTRATE IN RAT CEREBRAL CORTEX SLICES: IMPORTANCE OF CYTOPLASMIC NAD(P)H AND POTASSIUM
Authors: Bull R. J. 
Published: October 2006

Abstract—Using dual‐wavelength absorbance spectrophotometry, the ability of various substrates to produce and maintain a redox potential in the cytochrome chain of rat cerebral cortex slices was studied. In general, the ability to reduce the cytochromes parallels previously reported capabilities of the substrates to support metabolic responses to stimulation. The steady‐state kinetics of cytochrome reduction by glucose or lactate displayed a very sharp dependency upon concentration in the regions of 1 or 3 mm, respectively. This was in contrast to a near linear reduction of the cytochromes with concentrations of pyruvate over a range of 1–10 mm. The production and maintenance of a cytochrome redox potential was found to be at least partially dependent upon the presence of potassium (3 mm in the incubation media). Reduction of the cytochromes attributable to potassium was inhibited by ouabain, indicating that intracellular potassium was the important variable.Addition of glucose or lactate to 'starved’ tissues was found to result in a complex cycle of oxidation and reduction of tissue NAD(P)H. A small initial reduction of NAD(P) was followed by an oxidation of NAD(P)H which occurred in an all‐or‐none fashion with reduction of the cytochromes. The oxidation of NAD(P)H and reduction of cytochrome b appeared to occur with a similar time course.Respiratory changes following addition of glucose were complex in time course, but established a new steady‐state rate 0.41 μmol/g per min above the preaddition rate in 10–12 min. Despite a similar level of reduction in the cytochrome chain, stimulation of respiration by pyruvate was only about 50% of the rate observed with addition of glucose. However, stimulation of respiration by addition of equim concentrations of pyruvate and lactate was found to be additive, producing a 0.48 μmol/g per min increase in the steady‐state rate of oxygen consumption.These data seem to support the conclusion that the cytoplasmic reducing equivalent derived from the initial oxidation of glucose or lactate plays an important, perhaps regulatory, role in the respiration of cerebral tissues.
CHOLINE UPTAKE BY CHOLINERGIC NEURON CELL SOMAS
Authors: Suszkiw J. B. , Beach R. L. , Pilar G. R. 
Published: October 2006

AbstractThe cellular compartments of ciliary ganglia take up choline by a single, saturable process with Km=7.1 × 10−5 M and Vmax= 4.66 pmol/min per ganglion: Denervation of the ganglia and the resultant degeneration of nerve terminals caused no significant decrease of the rate of accumulation of choline by the ganglia. This indicates that the measured uptake is by the postganglionic ncurons and nonneural elements (NNE: glial and connective tissue cells) in the ganglia. This uptakc is not dependent on metabolic energy and is not affectcd by lowcring Na+ or raising K+ concentrations in the incubating mcdia but is depressed in the presence of ouabain and hemicholinium‐3. The presence or Na+‐dependent. rapidly saturable uptake in the preganglionic nerve terminals which is not detectablc kinetically is, however, inferred from a decrease in ACh synthesis in dcncrvatcd prcparations and a similar decrcasc in intact ganglia incubated in low Na+ solution.
REGIONAL DISTRIBUTION OF GLUTAMATE DECARBOXYLASE AND GABA WITHIN THE AMYGDALOID COMPLEX AND STRIA TERMINALIS SYSTEM OF THE RAT
Authors: Ben‐Ari Y. , Kanazawa I. , Zigmond R. E. 
Published: October 2006

AbstractThe distribution of glutamate decarboxylase (GAD) and δ‐amino butyric acid have been studied in the amygdaloid complex and in the stria terminalis system of the rat. The central and medial nuclei of the amygdala had significantly higher activities of GAD than the lateral olfactory tract nucleus, anterior amygdala, anterior lateral nucleus, posterior lateral nucleus, cortical nucleus, basomedial nucleus, basolateral nucleus, and pyriform cortex. The enzyme activity was about two and a half times higher in the central and medial nuclei than in the pyriform cortex. GABA was also significantly more concentratcd in these nuclei than in the pyriform cortex although this was not true for four other amino acids studied–glutamic acid, aspartic acid, taurine and glycine. GAD activity was also measured in the stria terminalis (the major afferent and efferent pathway of the amygdala) and in its bed nucleus. The enzyme activity was higher in the stria terminalis than in four other fibre tracts studied–the optic tract, anterior commissure, corpus callosum, and fimbria. GAD activity was exceptionally high in the bed nucleus of the stria terminalis particularly in its ventral part. The significance of the results are discussed in terms of what is known about the evolution and anatomy of the amygdala.
INHIBITION OF SYNAPTOSOMAL NORADRENALINE UPTAKE BY VERATRIDINE, GRAMICIDIN D AND VALINOMYCIN
Authors: White T. D. 
Published: October 2006

Abstract— —The effects of brief exposures of rat brain synaptosomes to veratridine, gramicidin D and valinomycin on noradrenaline uptake were investigated. All three drugs inhibited the Na+‐dependent component of noradrenaline uptake by synaptosomes. These effects were independent of extracellular Ca2 + concentrations, indicating that the reductions were not due to the release of newly accumulated noradrenaline.Gramicidin D reduced the Vmax for noradrenaline uptake, whereas veratridine and valinomycin reduced the Vmax and also increased the Vm for uptake.Most of these findings can be explained on the basis of the effects that these drugs have on the inward‐directed electrochemical gradients for Na+ across synaptosomal membranes, although, in the cases of veratridine and valinomycin, the elevated Km's suggest that an impairment of noradrenaline binding to its carriers might also be involved.
IN VIVO LABELLING OF ACETYL‐ASPARTYL PEPTIDES IN MOUSE BRAIN FROM INTRACRANIALLY AND INTRAPERITONEALLY ADMINISTERED ACETYL‐l‐[U‐14C] ASPARTATE
Authors: Sinichkin A. , Sterri S. , Edminson P. D. , Reichelt K. L. , Kvamme E. 
Published: October 2006

Abstract— Following intracranial and intraperitoneal injection of acetyl‐l‐[U‐14C]aspartate into mice about 5% and 0.7% of the radioactivity, respectively, was recovered from the brain after 30 min.On chromatographic separation of the cationic and anionic compounds on a Dowex 50 column, the former fraction contained about 60% of the radioactivity, predominantly as labelled aspartate and glutamate. The anionic compounds, containing 20% of the labelled compounds, were fractionated in several chromatographic systems and resolved into a great variety of labelled peptidic compounds of which five acetyl‐[U14‐C]aspartyl peptides, containing two to four amino acids, were purified. One of these, acetyl‐aspartyl glutamine, has not previously been found in brain.