bluuebunny/crossref_metadata_2025 huggingface dataset:
PROTEINS OF HUMAN BRAIN TISSUE OBTAINED DURING SURGICAL PROCEDURES
Authors: Cain D. F. , Ball E. D. , Dekaban A. S.
Published: October 2006

Abstract— A series of normal and abnormal brain tissues were obtained during surgical procedures; adjacent portions were evaluated histologically or extracted with dilute buffer. The proteins were separated in acrylamide gels using electrophoresis and isoelectric focusing. Twelve of the patients showed a very similar distribution of the proteins on electrophoretic separation referred to as the ‘typical’ pattern. This group includes all of the histologically normal specimens, and in addition, one mild gliosis, two cases of juvenile lipidosis, one mucopolysaccharidosis and one Unverricht epilepsy. Remarkably little variability in the electrophoresis gel pattern was found in a series of five pairs of histologically normal gray and white matter samples. An increased density of several bands was apparent in extracts of gray matter when compared with corresponding white. No differences which could be correlated with the different areas of the cortex were seen.

Six of the patients showed gel patterns different from the ‘typical’ pattern. One of these (glioblastoma) differed only in the increase in band 9. Another glioblastoma showed a virtual absence of nearly all of the brain proteins usually found in the gels. Two astrocytomas and one surgical scar specimen showed a very dense protein band (No. 15) and a novel minor protein component, band 20, while one case of SSPE showed only the heavy band in the area of band 15. The content of band 5 was reduced in those specimens which presented a dense band 15. The pronounced increase in band 15 and band 20 appears to correlate with the marked increase in astrocytic elements in these three patients.
NEURONAL CELL BODY ENRICHED AND GLIAL CELL ENRICHED FRACTIONS FROM YOUNG AND ADULT RAT BRAINS: PREPARATION AND MORPHOLOGICAL AND BIOCHEMICAL PROPERTIES
Authors: Nagata Y. , Mikoshiba K. , Tsukada Y.
Published: October 2006

—A technique for separating neuronal and glial cell fractions in bulk from rat brain has been developed which does not use any digestive enzymes. Carbonic anhydrase, S‐100 protein and 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase were associated with the glial fraction. Glutamate and aspartate were the most abundant free amino acids; the neuronal fraction was richer in GABA and glycine than the glial fraction. Both d‐glutamate and potassium ions were actively accumulated in each fraction during aerobic incubation. Na,K‐ATPase was higher in the glial fraction; its activity, especially in the glial fraction, increased rapidly from the 10th to the 20th day after birth. Lactate dehydrogenase showed higher activity in the neuronal than in the glial fraction during early development; its isozyme pattern in each fraction was similar to that of whole brain. Acetylcholine esterase had its maximum activity around the 15th day in both fractions. Limitations of this bulk separation technique are discussed.
FLUID SPACES OF SYNAPTOSOME BEDS
Authors: Heaton G. M. , Bachelard H. S.
Published: October 2006

—The fluid spaces of synaptosome beds were estimated by vol. measurement and also by a combination of chemical and enzymic analyses. The extra‐synaptosomal space of the beds was concluded to be about 80 per cent of their total vol. Beds prepared by conventional techniques after sucrose density‐gradient centrifugation were found to contain 0‐08 M‐sucrose within the synaptosomes.
THE MECHANISM OF THE EXCLUSION OF SODIUM IONS AND THE CONCENTRATION OF POTASSIUM IONS BY GUINEA‐PIG CEREBRAL CORTEX SLICES
Authors: Hillman H. , Stollery Susan , Joanny P.
Published: October 2006

—Guinea pig cerebral slices were incubated in oxygenated Krebs‐Ringer bicarbonate glucose saline for periods of 1 s to 60 min, and their swelling and Na+ and K+ cone were measured. The swelling was at the rate of 8 per cent for the 1st min, and 0·8 per cent for the next 29 min; it fell significantly during the subsequent 30 min (P= 0·05). The Na+ and K+ concn in the tissue fluctuated during the 1st min of incubation, but the Na+ concn had risen to a mean of 108 mm after 1 min incubation and the K+ concn had fallen to a mean of 52 mm by 3 min. The concentrations of these cations did not change significantly after these times. Cerebral slices were also incubated for 30 min in isotonic media modified such that Na+, + K+, Na++ choline+, or K++ choline+ always added up to 150 mm. It was found that about half of the swelling (20‐25 per cent) was independent of the Na+ or K+ concn and a further 20‐25 per cent of the swelling varied with the cations only if Na+ and K+ were both present and was a function of the K+ concn in the medium (0·15 per cent m‐mol). The Na+ concn in the tissue was a mean 8·4 mm after incubation in a Na+‐free medium and 7·1 mm in K+ after incubation in a K+‐free medium. Cerebral slices in the presence of Na++ K+ excluded one molecule of Na+ for every four molecules in the incubating medium; they accumulated K+ from the medium until the concn in the medium exceeded 130 mm.
EFFECT OF PHOSPHOLIPASES A AND C ON FREE AMINO ACID CONTENT OF THE SQUID AXON1
Authors: Rosenberg P. , Khairallah E. A.
Published: October 2006

Abstract— Squid axonal preparations consisting of the giant axon plus adhering small nerve fibres were incubated for 30 min with phospholipase A (1, 0.2 and 0.025 mg/ml); phospholipase C (10 and 0.5 mg/ml) or lysolecithin (1 and 0.2 mg/ml) followed by another 30 min incubation in normal sea water. The axoplasm and envelope (sheath) of the axonal preparation were then separated and the phospholipids and free amino acids determined. The released amino acids were also measured in the incubation solutions. Compared to phospholipase C, phospholipase A caused a much greater reduction in the free amino acid content of axoplasm and envelope; and a concomitant much greater increase in amino acids released into the incubation solutions, even when phospholipase A was used in concentrations which caused less phospholipid splitting than phospholipase C. Lysolecithin had a much weaker effect than phospholipase A. It is concluded that disruption of hydrophobic binding has a much greater effect on the structure of the non‐lipid portion of the axonal membranes than does disruption of hydrophilic (electrostatic) forces of interaction. Our results can be interpreted in terms of the protein‐crystal or mosaic models of membrane structure whereas they do not support the unit membrane hypothesis.
BRAIN ACETYLCHOLINE AND CHOLINESTERASE: EFFECT OF PHENOTHIAZINES AND PHYSOSTIGMINE INTERACTION IN RATS1
Authors: Sethy V. H. , Van Woert M. H.
Published: October 2006

Abstract— The effect of phenothiazines either alone or in combination with physostigmine on whole brain acetylcholine concn and cholinesterase activity has been investigated in male rats. Phenothiazines (chlorpromazine, trifluperazine and thioridazine) when injected alone had no significant effect on brain acetylcholine concentration. Pretreatment with chlorpromazine and thioridazine significantly enhanced the physostigmine‐induced increase in brain acetylcholine concn and inhibition of cholinesterase activity. However, trifluperazine had no significant effect on the physostigmine‐induced increase in brain acetylcholine concentration and inhibition of cholinesterase activity. The potentiation of the physostigmine‐induced increase in brain acetylcholine concn by phenothiazines may be due to (1) increased acetylcholine turnover secondary to the blockade of dopamine receptors by neuroleptic drugs and.
CEREBROSPINAL FLUID HOMOVANILLIC ACID AND ISO‐HOMOVANILLIC ACID: A GAS–LIQUID CHROMATOGRAPHIC METHOD
Authors: Dziedzic S. W. , Gitlow S. E.
Published: October 2006

Abstract— The hexafluoroisopropyl esters of trifluoroacetylated homovanillic acid (HVA) and 3‐hydroxy‐4‐methoxyphenylacetic acid (iso‐HVA) were the derivatives chosen for assay of these phenolic acids in lumbar cerebrospinal fluid (CSF) specimens from 65 control subjects. The mean value obtained in these specimens was 40.0 ± 23.5 ng/ml. Recovery of added HVA and iso‐HVA was 94 ± 2 per cent and reproducibility was ±5 per cent. CSF from Parkinson's disease patients undergoing treatment with l‐DOPA showed significant increases in HVA. Iso‐HVA was detected in those CSF samples obtained during l‐DOPA therapy.
NH2‐TERMINAL ANALYSIS OF WOLFGRAM AND FOLCH‐LEES PROTEOLIPID PROTEINS1
Authors: Wiggins R. C. , Valle U. Del , Joffe S.
Published: October 2006

Abstract— The NH2‐terminal amino acids of Wolfgram and Folch‐Lees proteolipids of bovine and human CNS myelin were determined using the cyanate method (Starke & Smyth, 1963) followed by direct amino acid analysis of the products. Glycine predominated in every case and was recovered in amounts similar to the results described by Whikehart & Lees (1973), who used a dansylation technique followed by thin layer chromatography of the DNS‐amino acids. In the present study substantial amounts of glutamic acid, serine, alanine and aspartic acid were also recovered, plus traces of other amino acids. Few differences were observed between Wolfgram and Folch‐Lees proteolipids. The end group products of purified W1 proteolipid of bovine Wolfgram fraction, of diazometholysed Folch‐Lees proteolipid, and of a sample of phosphatidyl serine had essentially the same composition. The similarity of these results, especially for both fractionated and unfractionated Wolfgram proteolipid, may be evidence that the observed products are derived from phosphoglycerides present in proteolipid rather than from the actual NH2‐terminals of the protein.
PREPARATION OF SYNAPTOSOMES AND VESICLES WITH SODIUM DIATRIZOATE1
Authors: Tamir H. , Rapport M. M. , Roizin L. , Huang Y. L. , Liu J. C.
Published: October 2006

Abstract— Synaptosomes were prepared from rat brain on a continuous gradient of sodium diatrizoate and compared with synaptosomes obtained on a discontinuous sucrose gradient. The yield of synaptosomal protein using diatrizoate was double that obtained with sucrose. No significant differences in quality between the two preparations were found based on measurement of: β‐glucuronidase, RNA polymerase, 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase, total and Na+, K+ ‐ATPase, acetylcholinesterase, lactic acid dehydrogenase, glucose utilization, and serotonin uptake. Electron microscopy showed the vesicles in the diatrizoate synaptosomes to be better preserved. Vesicles prepared on diatrizoate segregated into two distinct bands which differed in electron microscopic appearance and enzyme activity. The less dense vesicles were smaller, had much higher Mg2+ ‐ATPase activity, and a lower content of acetylcholinesterase than the more dense vesicles. The less dense vesicle preparation was very homogeneous morphologically, free of myelin and mitochondria, and contained occasional organelle fragments and double membrane structures.
METHYLASES OF MYELIN BASIC PROTEIN AND HISTONE IN RAT BRAIN
Authors: Miyake M.
Published: October 2006

—The two enzymes methylating myelin basic protein and histone were purified 170‐ and 250‐fold respectively from the cell sap fraction of rat brain. These enzymes methylated only arginine residues of the two proteins. The enzyme activities were present in all organs tested. Testis has the highest, brain a moderate and liver the lowest activity. Most of the activities were present in the cell sap fraction in brain, liver and testis. Methylation of myelin basic protein and histone was examined in both the cell sap and solubilized nuclear fraction of rat brain during life span after birth. The myelin basic protein methylating activity in the cell sap fraction increased during myelination. Histone methylase from the nuclear fraction was highest at birth and dropped rapidly thereafter. The other activities remained unchanged. The natural occurrence of NG‐mono‐ and NG,NG‐dimethylarginine residues in histones prepared from rabbit liver was demonstrated.
EFFECT OF UNILATERAL VISUAL DEPRIVATION AND VISUAL STIMULATION ON THE ACTIVITIES OF ALKALINE PHOSPHATASE, ACID PHOSPHATASE, Na+−K+ ACTIVATED Mg2+ CATALYSED ADENOSINE TRIPHOSPHATASE AND ON THE CONTENT OF SODIUM AND POTASSIUM IONS OF THE OPTIC LOBE OF ADULT PIGEON
Authors: Chakrabarti T. , Daginawala H. F.
Published: October 2006

—A study was made of the effects of unilateral visual deprivation and stimulation upon the activities of alkaline phosphatase (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), Na+‐K+ activated Mg2+ catalysed ATPase (EC 3.6.1.4) and upon the Na+ and K+ contents of the optic lobe of adult pigeon (Columba livia). Visual deprivation was achieved by eyelid suturing or by enucleation and maintained for 1–9 weeks. Unilateral visual stimulation was maintained for 75 min following 72 h of darkness. A statistically significant increase in the activity of alkaline phosphatase activity was observed in the optic lobe after unilateral visual deprivation whereas unilateral visual stimulation resulted in the opposite effect. Acid phosphatase activity was found to be unchanged under all experimental conditions. Na+‐K+ ATPase activity was found to increase significantly following unilateral visual stimulation and following eyelid suturing in the corresponding optic lobes; unilateral enucleation resulted in a decrease in the Na+‐K+ ATPase activity. An increase in the enzyme activity was found to be associated with an increase in the level of Na+‐ion and a decrease in the level of K+‐ion, and vice versa.
SHIFTS IN UBIQUINONE REDOX STATUS OF RAT BRAIN IN VITRO WITH CATIONIC STIMULATION
Authors: Klicpera J. A. , Hoffmann P. C.
Published: October 2006

–Changes in respiratory rate, ubiquinone (Q) redox status, lactate and pyruvate levels in chopped rat telencephalon were studied after cationic stimulation of respiration. When chopped telencephalon was incubated with glucose as substrate, increasing the K+ concentration from 5 mm to 55 mm was associated with a 57% increase in the respiratory rate and a reduction in Q redox status from 76% oxidized to 64% oxidized. Lactate increased by over 200%. Substitution of pyruvate for glucose with 5 mm‐K+ resulted in a respiratory rate that was 78% of that seen with glucose and 55 mm‐K+. Increasing K + from 5 mm to 55 mm increased the respiratory rate by only 6%, with pyruvate as substrate. Q underwent a reduction that was half that seen with glucose. Ouabain largely prevented the K +‐induced increase in respiratory rate with glucose as substrate, but Q was still reduced by 5 percentage points while lactate and pyruvate were unchanged. When respiration was uncoupled with 2,4‐dinitrophenol, increasing the K+ concentration from 5 mM to 55 mm had no further effect on any of the metabolic parameters measured. Deletion of Ca2+ from the medium resulted in an increase in respiration of 18%, but neither the Q redox status nor the levels of lactate or pyruvate were significantly changed. The results demonstrate that the K+‐induced stimulation of respiration results from a coordinated metabolic response whereas the stimulation of respiration associated with Ca2+ depletion is probably mediated through ion fluxes at the cell membrane and activation of Na+‐K+‐activated ATPases.
STRUCTURAL ALTERATIONS OF AMINO ACIDS AT THE LEVEL OF AMINOACYL‐tRNAS: TRANSFORMATION OF DICARBOXYLIC AMINO ACIDS
Authors: Roux Huguette , Murthy M. R. V.
Published: October 2006

Abstract— Radioactive glutamate, glutamine, aspartate and asparagine were incorporated into calf brain tRNA in the presence of homologous aminoacyl‐tRNA synthetases. When the aminoacyl‐tRNAs were deaminoacylated and the products chromatographed in the phenol solvent, the glutaminyl‐and asparaginyl‐tRNAs showed two products GnP2 and AnP2 respectively, in‐ addition to the original amino acids. These new substances moved close to the solvent front in contrast to glutamine and asparagine which had much lower RF values. Attachment of the amino acids to tRNA appeared to be a prerequisite for the formation of these substances, since they were not found in the reaction mixture used for aminoacylation in the absence of incubation or on omission of tRNA or when tRNA was degraded by RNase. Application of the deaminoacylation procedure to pure amino acids also failed to lead to their formation. In an other series of experiments, the dicarboxylic aminoacyl‐tRNAs were hydrolysed with pancreatic RNase and then analysed by high voltage paper electrophoresis. Again, the glutaminyl‐ and asparaginyl‐tRNAs showed two new components, GnE3 and AnE3, in addition to the expected glutaminyl‐ and asparaginyladenosines. GnE3 and AnE3 exhibited much faster electrophoretic mobilities in the direction of the cathode than the adenosine derivatives of the original amino acids and thus appeared to be more positively charged. The presence of these new compounds in the products of deaminoacylation or in R Nase hydrolysates was specific to glutaminyl‐ and asparaginyl‐tRNAs and did not occur in the case of either glutamyl or aspartyl‐tRNAs, indicating that the amide group was probably involved in the transformation reaction.
METABOLISM OF POLYAMINES IN MOUSE NEUROBLASTOMA CELLS IN CULTURE:1 FORMATION OF GABA AND PUTREANINE
Authors: Kremzner L. T. , Hiller J. M. , Simon E. J.
Published: October 2006

—Polyamine metabolism of mouse neuroblastoma cells grown in culture was studied with special reference to the synthesis of GABA from putrescine and putreanine from spermidine. This study shows that neuroblastoma cells in the presence of a complete culture medium containing calf serum readily metabolized [14C]putrescine to GABA; the rate of synthesis is similar to the rate of synthesis of spermidine from putrescine. In the absence of serum the conversion of putrescine to GABA is minimal. In the presence of serum GABA formation is completely inhibited by the diamine oxidase inhibitor aminoguanidine. GABA synthesis does not occur in the absence of cells. The GABA synthesized is not readily metabolized to succinate or homocarnosine. Mouse neuroblastoma cells metabolized [14C]ornithine to putrescine, GABA, and spermidine. Spermidine was metabolized to putrescine, putreanine and spermine.
EFFECTS OF DEXAMETHASONE AND NERVE GROWTH FACTOR ON PHENYLETHANOLAMINE N‐METHYLTRANSFERASE AND ADRENALINE IN ORGAN CULTURES OF NEWBORN RAT SUPERIOR CERVICAL GANGLION
Authors: Phillipson O. T. , Moore K. E.
Published: October 2006

Abstract— Phenylethanolamine N‐methyltransferase (PNMT) and adrenaline (A) have been studied in organ cultures of neonatal rat sympathetic ganglia. Organ culture for 2 days without added nerve growth factor (NGF) caused a fall in noradrenaline (NA) and PNMT contents but there was no change in dopamine (DA) or A contents compared to controls. However, in the presence of dexamethasone, there was a marked increase in both PNMT activity and A content, but no change in NA or DA content. Addition of NGF to cultures stimulated with dexamethasone caused no further significant change in PNMT activity or A content, whereas both NA and DA were increased. Prolonged culture without NGF, in the presence of dexamethasone resulted in reductions in both NA and DA content, but the high levels of PNMT activity and A content were sustained. The results are consistent with the hypothesis that both PNMT and A are not contained in the noradrenergic cell bodies but are located chiefly within the small intensely fluorescent cells in sympathetic ganglia.
THE BIOSYNTHESIS OF CHOLESTEROL AND OTHER STEROLS BY BRAIN TISSUE: DISTRIBUTION IN SUBCELLULAR FRACTIONS AS A FUNCTION OF TIME AFTER INJECTION OF [2‐14C]MEVALONIC ACID, SODIUM [2‐14C]ACETATE AND [U‐14C]GLUCOSE INTO 15‐DAY‐OLD RATS
Authors: Jones J. P. , Rios A. , Nicholas H. J. , Ramsey R. B.
Published: October 2006

Abstract—

The distribution of [14C]‐labelled material into subcellular fractions of 15‐day‐old rat brain was studied at 2 and 24 h following intraperitoneal and intracerebral injection of [2‐14C]sodium acetate, [U‐14C]glucose and [2‐14C]mevalonic acid respectively. The total quantity of labelled isoprenoids in the brain was, except for glucose, greater when the precursor was administered intracerebrally. The intraperitoneal route was more advantageous in the case of [U‐14C]glucose. The subcellular distribution of both labelled total isoprenoid material and sterol was distinct for each labelled precursor. Intracerebrally injected [U‐14C]glucose at both time periods studied suggested no dominance of labelling in any fraction. After intraperitoneal injection of [U‐14C]glucose the microsomes were more prominently labelled. Both methods of administration of sodium [2‐14C]acetate resulted in heavy labelling of the myelin fraction after 24 h. The total labelled isoprenoids resided mainly in the microsomes 24 h after injection of [2‐14C]mevalonic acid. Labelled sterol was found to be localized more in the myelin and microsomal fractions for all three precursors than was the labelled total isoprenoids. Depending on the type of experiment to be conducted, each of these precursors can give different results, which must be interpreted accordingly.
INJECTION OF 6‐HYDROXYDOPAMINE AND HYDROGEN PEROXIDE INTO THE SUBSTANTIA NIGRA AND LATERAL VENTRICLE OF THE CAT: SPECIFIC AND NONSPECIFIC EFFECTS ON STRIATAL BIOGENIC AMINES1
Authors: Stahl S. M. , Daniels A. C. , Derda D. , Spehlmann R.
Published: October 2006

Abstract—

Attempting to clarify the mechanism by which intracerabral injection of 6‐hydroxydopamine (60HDA) reduces catecholamines in the caudate nucleus (CN), we have tested two hypotheses: (1) 60HDA specifically attacks catecholaminergic neurons; (2) 60HDA liberates hydrogen peroxide (H2O2) which destroys neurons indiscriminately. To this end, we have injected high or low doses of 60HDA or equimolar amounts of H2O2 stereotaxically into the substantia nigra (SN) or the lateral ventricle of cats and have placed electrocoagulative lesions in the SN. We determined the CN levels of dopamine (DA), norepinephrine (NE) and serotonin (5HT) 7‐10 days later. Nigral injections of high doses (8 μ mol) of either agent or low doses (80 nmol) of 60HDA decreased both DA and NE and induced similar histologic damage in the SN with neuronal drop‐out at the periphery of the lesions. Injection of 80 nmol of H2O2 into the SN did not decrease CN amine levels and did not produce histologic damage in the SN. Electrocoagulation of the SN decreased CN DA and NE, but the histologic lesions failed to show any peripheral neuronal drop‐out. Ventricular injections of high doses (16 μmol) of 60HDA or H2O2 reduced not only DA and NE but also 5HT levels in the ipsilateral CN. Low intraventricular doses (0‐16 μmol) of 60HDA decreased only DA and NE without affecting 5HT levels in the CN whereas 0.16 μmol of H2O2 had no effect on any of the CN amines. The catecholamine‐depleting effects of low doses (80 nmol) of 60HDA were significantly potentiated by inhibiting brain monoamine oxidase by 90 percent or more at the time and site of injection of 60HDA. These results suggest that the extracellular liberation of H2O2 from 60HDA could explain some possibly nonspecific effects of high doses of 60HDA; at lower doses, however, 60HDA may act via selective uptake into catecholaminergic neurons with subsequent intracellular release of H2O2.
A RELATIONSHIP OF N‐ACETYLASPARTATE BIOSYNTHESIS TO NEURONAL PROTEIN SYNTHESIS12
Authors: Clarke D. D. , Greenfield S. , Dicker E. , Tirri L. J. , Ronan E. J.
Published: October 2006

Abstract—

A detailed time study of the incorporation of label from sodium‐[1‐14C]acetate, [1‐14C]ethanol, and [2‐14C]glucose into the aspartyl moiety of N‐acetylaspartic acid (NAA) was conducted. As expected the specific activity of aspartate increased rapidly with time and peaked within 15‐20 min after which it fell sharply; but significantly, that of the aspartyl moiety of NAA rose very slowly even after the specific activity of aspartate had fallen to less than 1 per cent of the peak values.

A rat brain microsomal free supernatant preparation was shown enzymatically to incorporate label from sodium‐[1‐14C]acetate into the t‐RNA fraction from which was isolated N‐[1‐14C]acetylaspartic acid. From these observations we were inclined to speculate that NAA‐t‐RNA may serve as an initiator of neuronal protein synthesis.
TAURINE UPTAKE IN SYNAPTOSOMAL FRACTIONS OF RAT CEREBRAL CORTEX1
Authors: Schmid R. , Sieghart W. , Karobath M.
Published: October 2006

Abstract— [35S]Taurine was found to be accumulated in synaptosomal fractions of rat cerebral cortex. Kinetic analysis in the range of 1–800 μm‐[35S]taurine revealed at least two different uptake processes. A high affinity uptake with a Km of 20 μM and a low affinity uptake with a Km of about 450 μM. The high affinity component was dependent on temperature and energy, and virtually abolished in the absence of sodium. Examination of the influence of structural analogues and putative transmitter substances indicates that the high affinity uptake of taurine into synaptosomal fractions of rat cerebral cortex is unique and highly specific. No specific actions of several centrally acting drugs on taurine uptake could be observed.
THE VISUALIZATION OF CONCANAVALIN‐A BINDING SITES IN THE INTERPERIOD LINE OF RAT SCIATIC NERVE MYELIN
Authors: Wood J. G. , McLaughlin Barbara J.
Published: October 2006

Abstract—

The plant lectin, Concanavalin A (Con A), is used in combination with a peroxidase‐labelling technique to visualize carbohydrates in myelin. The major myelin glycoprotein seen by polyacrylamide electophoresis binds Con A. Thin slices of sciatic nerve bind Con A in the interperiod line of the myelin. These data suggest that the glycoprotein may be located at the interperiod line.
CATECHOLAMINES IN SYMPATHETIC GANGLIA OF RAT: EFFECTS OF DEXAMETHASONE AND RESERPINE1
Authors: Koslow S. H. , Bjegovic M. , Costa E.
Published: October 2006

Abstract—

The superior cervical sympathetic ganglion of rats contains a finite amount of epinephrine all of which is of ganglionic origin. Treatment of new‐born rats with dexamethasone for 8 days results in a 112‐fold increase in the epinephrine concentration, whereas the norepinephrine and dopamine are increased by only 1·4‐ and 1·9‐fold respectively. This epinephrine increase in newborn rats is reversible if treatment is discontinued, and it fails to occur in adult animals. The epinephrine store of normal and dexamethasone treated animals is resistant to the depletion by reserpine. There is no increase in the epinephrine content in organs innervated by axons emanating from the ganglion. The data presented support the localization of epinephrine in small intensely fluorescent cells in the ganglion and we propose that epinephrine may be released from these cells and function as a modulator of ganglionic transmission.
PROPERTIES OF TYROSINE HYDROXYLASE IN PERIPHERAL NERVES
Authors: Numata (Sudo) Y. , Nagatsu T.
Published: October 2006

Abstract—

Approximately 80 per cent of tyrosine hydroxylase activity in bovine mandibular nerve and rabbit sciatic nerve was soluble, and the rest of the activity was particle‐bound. The soluble enzyme in bovine mandibular nerve was isolated by ammonium sulphate fractionation (25–35 per cent saturation). The enzyme had a pH optimum at 5·9 in Tris‐acetate buffer, and at 6·5 in Tris‐HCl or phosphate buffer. The enzyme required a tetrahydropteridine cofactor. Km values toward various tetrahydropteridines such as l‐erythro‐tetrahydrobiopterin (a probable natural cofactor), 2‐amino‐4‐hydroxy‐6‐methyltetrahydropteridine, and 2‐amino‐4‐hydroxy‐6,7‐dimethyltetrahydropteridine were 2 × 10−5m, 5 × 10−5m and 4 × 10−4m, respectively. The Km value for tyrosine at 1 × 10−3m‐2‐amino‐4‐hydroxy‐6‐methyltetrahydropteridine as a cofactor was 5 × 10−5m. The enzyme activity was markedly stimulated with Fe2+ or catalase, but Fe2+ gave higher activity. The activity was inhibited with α, α′‐dipyridyl, l‐α‐methyl‐p‐tyrosine, and various catecholamines. Among catecholamines, dopamine was the most potent inhibitor. l‐5‐Hydroxytryptophan was an inhibitor as potent as dopamine. Neither d‐5‐hydroxytryptophan nor 5‐hydroxytryptamine inhibited the enzyme. The inhibition by l‐5‐hydroxytryptophan was partially competitive with tetrahydrobiopterin at concentrations higher than 9 × 10−5m, and partially uncompetitive at concentrations lower than 9 × 10−5m. The addition of heparin or lysolecithin did not affect enzyme activity with tetrahydrobiopterin as cofactor.
BRAIN LIPID COMPOSITION OF IMMATURE THIAMINE‐DEFICIENT AND UNDERNOURISHED RATS1
Authors: Geel S. E. , Dreyfus P. M.
Published: October 2006

Abstract—

The brain lipid composition of 25‐day‐old offspring of rats exposed to dietary thiamine (vitamin B1) deficiency from the 14th day of gestation was examined and compared to normal and pair‐fed (undernourished) controls. Thiamine‐deprived rats displayed neurological signs and a marked diminution of growth at 25 days of age. No changes in brain lipids of either whole brain or selected brain areas (brain stem, cerebellum, diencephalon) which were distinct from the effects of undernutrition (pair‐fed controls) were observed in the thiamine‐deficient group. Undernutrition, as exemplified by the pair‐fed control group produced a highly significant depression of all lipids expressed per total brain and a significant deficit of whole brain and regional lipid, cerebroside and cholesterol concentrations indicating a deficiency in myelinogenesis. Ganglioside NeuNAc concentration was shown to be significantly greater in whole brain and certain brain areas of the same group while no changes were evident in total phospholipid concentration and the distribution of individual phospholipids. The implications of these findings in terms of the pathophysiology of thiamine‐deficiency encephalopathy and undernutrition in early life are discussed.
PURIFICATION AND PROPERTIES OF ARYLSULPHATASE FROM THE BRAIN OF THE SILKWORM BOMBYX MORI
Authors: Farooqui A. A. , Yusufi A. N. K.
Published: October 2006

Abstract—

(1)Arylsulphatase of the silkworm Bombyx mori was partially purified using ammonium sulphate fractionation, ethanol precipitation, Sephadex G–200 gel filtration and Con‐A Sepharose chromatography.

(2)The purified enzyme preparation was not homogeneous but showed no β‐glucuronidase or β‐galactosidase activities.

(3)The kinetic properties of the enzyme indicated that it could be classified under type‐2 arylsulpha‐tases of vertebrates.

(4)The purified enzyme shows very little activity towards p‐nitrophenyl sulphate and none towards cerebroside 3‐sulphate
THE DISTRIBUTION OF CHOLINE ACETYLTRANSFERASE ACTIVITY IN VERTEBRATE RETINA1
Authors: Ross C. D. , McDougal D. B.
Published: October 2006

Abstract— Choline acetyltransferase (ChAc) activity was determined in retinal layers from 10 vertebrates. In all animals, the highest activity was in the inner plexiform layer, intermediate activity in the inner nuclear and ganglion cell layers, and very low activity in the photoreceptor and outer plexiform layers and optic nerve. The pattern of distribution of enzyme activity within the inner nuclear layer corresponds quantitatively to the distribution of amacrine cells within that layer. A species difference of almost 90‐fold was found between the lowest and highest values for ChAc activity in inner plexiform layer. The variation in enzyme activity found among homeotherms in inner nuclear and inner plexiform layers is related to the number of amacrine cell synapses in the inner plexiform layer. But the differences in enzyme activity are generally greater than those which have been found in numbers of amacrine cell synapses between species. The data suggest that cholinergic neurons in retina are to be found predominantly among the amacrine cell types and that not all amacrine cells will be found to be cholinergic.
BRAIN TYROSINE HYDROXYLATION: ALTERATION OF OXYGEN AFFINITY IN VIVO BY IMMOBILIZATION OR ELECTROSHOCK IN THE RAT
Authors: Davis J. N.
Published: October 2006

Abstract— The rates of brain tyrosine and tryptophan hydroxylation, estimated in vivo from the accumulation of DOPA and 5‐hydroxytryptophan after the administration of a decarboxylase inhibitor, appear dependent on the availability of oxygen as a substrate. During two types of physical stress, electroshock and curare‐immobilization, the rate of brain tyrosine hydroxylation was greater than in unstressed controls and was not significantly decreased when the stresssed animals were made hypoxic. The loss of oxygen dependence by brain tyrosine hydroxylation during stress was observed in several brain regions and was not associated with alterations in the concentrations of brain tyrosine. tryptophan, serotonin, dopamine or norepinephrine. The rate of brain tryptophan hydroxylation was not affected by stress and remained oxygen dependent. The increase in catecholamine synthesis during stress appears to be the result of increased catecholaminergic nerve impulse flow. These experiments are consistent with the hypothesis that during neuronal stimulation an allosteric change in tyrosine hydroxylase increases the affinity of the enzyme for oxygen allowing greater catecholamine synthesis despite limiting concentrations of this substrate.
NEUROTOXICITY OF A NON‐METABOLIZABLE AMINO ACID, 1‐AMINOCYCLOPENTANE‐1‐CARBOXYLIC ACID: ANTAGONISM BY AMINO ACIDS IN CULTURES OF CEREBELLUM
Authors: Nixon R. A. , Suva Mila , Wolf M. K.
Published: October 2006

Abstract— The non‐metabolizable amino acid 1‐aminocyclopentane‐1‐carboxylic acid (ACPC) induced degeneration of myelinated axons but spared nerve cell bodies in well myelinated organotypic cultures of cerebellum. The ACPC concentrations used were comparable to those which induce axonal degeneration in vivo. Developing unmyelinated cultures were more sensitive to ACPC than mature cultures and newly myelinating axons appeared to be particularly affected. Supplementing the medium with amino acids, but not with vitamins, prevented toxicity at the lower concentrations of ACPC and afforded considerable protection against the highest concentrations. The protective effect of amino acids could not be accounted for by inhibition of intracellular ACPC transport. These results are considered in terms of other evidence indicating defective protein metabolism in ACPC‐treated mice.
EFFECTS OF DOPAMINERGIC AGONISTS AND ELECTRICAL STIMULATION OF THE MIDBRAIN RAPHÉ ON THE RELEASE OF 5‐HYDROXYTRYPTAMINE FROM THE CAT BRAIN IN VIVO
Authors: Chiueh C. C. , Moore K. E.
Published: October 2006

—The cerebroventricular system of spinal‐sectioned cats was perfused with artificial cerebrospinal fluid after the intraventricular administration of [3H]tryptophan, and the perfusate was analyzed for [3H]5‐HT. At the end of the experiment the relative contents of [3H]5‐HT in regions lining the cerebroventricular system (caudate nucleus, septum, hypothalamus) were essentially the same as the endogenous 5‐HT contents. Electrical stimulation of the midbrain raphé did not alter the efflux of total radioactivity but significantly increased the efflux of [3H]5‐HT. The addition of potassium to the perfusing CSF also increased the efflux of [3H]5‐HT, while additions of d‐amphetamine, apomorphine or l‐DOPA were without effect.
ATYPICAL INCORPORATION OF SINGLE AMINO ACIDS INTO MYELIN PROTEINS1
Authors: Johnson J. D. , King Neva L. , Binkley F.
Published: October 2006

—Purified myelin incorporated l‐[14C]leucine and l‐[14C]lysine into myelin proteins in an enzymatic process similar to that of renal brush border membranes. The system was not inhibited by cycloheximide or puromycin or by pretreatment with ribonuclease; the reaction was inhibited by cetophenicol. ATP was an effector, shifting the optimal pH from 7.2 to 8.3. In the presence of ATP, myelin was less dense in a sucrose gradient. Ammonia was released from the membrane during the incorporation of amino acids. Myelin preloaded with cold leucine did not incorporate [14C]leucine but did incorporate [14C]lysine; there was no cross inhibition between the two amino acids. The incorporation was into or onto proteins of the Wolfgram proteolipid fraction of myelin. The incorporation was of the high affinity type with a Km of 10−7m and was restricted to the natural amino acids.
EVOLUTION DE L'INCORPORATION IN VIVO DE L'ACIDE [14C]OROTIQUE DANS L'ARN ET L'ADN DU CERVELET DE JEUNES RATS HYPO‐ ET HYPERTHYROIDIENS: EFFETS COMPARATIFS DE L'HYPO‐ ET L'HYPERTHYROIDIE SUR LES MULTIPLICATIONS CELLULAIRES
Authors: Dainat J. , Rebière A.
Published: October 2006

Résumé—

L'evolution du poids du corps et du cervelet, de la quantité d'ARN, d'ADN et des protéines du cervelet. est étudiée jour aprés jour durant les 10 premiers jours de la vie postnatale et à 12, 14 et 17 jours chez des rats normaux, hypo‐ et hyperthyroïdiens.

Chez les animaux normaux: (1) Le contenu moyen des cellules en protéines diminue de 1 à 2 jours, augmente ensuitc jusqu'à un maximum à 4 jours, puis decroit réguliérement. (2) La RAS de I'ARN varie fortement de la naissance à 9 jours, et présente deux maxima à 4 et 6 jours. Aprhs 9 jours elle déroît fortement. (3) L'activite mitotique (nombre de cellules en phase de réplication) croït, passe par un maximum à 9 jours, puis décroït. (4) La RAS de I'ADN (pourcentage de la population cellulaire en phase de réplication) passe par un maximum à 6 jours. (5) Le rendement mitotique (nombre de cellules en phase de réplication rapportéà une même activité mitotique) dácroît irréguliirèment de 2 à 7 jours, puis augmente à nouveau.

Chez les animaux hypothyroïdiens: (1) Le contenu moyen des cellules en protéines, augrnente de 1 a 2 jours puis décroït rtgulièrement. (2) La RAS de I'ARN, significativement supérieure à la normale, varie fortement de la naissance à 9 jours et présente deux maxima à 4 et 6 jours; après 9 jours elle décroït fortement. (3) L'activité mitotique significativement inférieure à la normale, croït dépuis la naissance, passe par un maximum à 9 jours puis décroît. (4) La RAS de L'ADN non significativement diffèrente de la normale, passe par un maximum à 6 jours, puis décroît. (5) Le rendement mitotique n'est pas significativement différent de la normale.

Chez les animaux hyperthyroidïens: (1) Le contenu moyen des cellules en protkines, est maximum a 2 jours, puis decroit. (2) La RAS de I'ARN significativement inférieure à la normale, décroît depuis la naissance. (3) L'activite mitotique non significativement differente de la normale, croît depuis la naissance jusquèa un maximum à 6 jours, puis décroît. (4) La RAS de I'ADN significativement inférieure à la normale, augmente depuis la naissance jusqu'à 5 jours, puis decroît. (5) Le rendement mitotique est signiticativement superieur a la normale.

Dans les 3 groupes d'animaux. le maximum des divisions cellulaires est toujours précédé par une augmentation dc la taille moycnne des cellules. Chez les animaux hypothyroïdiens, le taux des morts cellulaires est supérieur à la normale et la taille moyenne des cellules l'est également durant les 14 premiers jours de la vie postnatale. Chez les animaux hyperthyroîdiens, le taux des morts cellulaires est inférieur à la normale et la taille moyenne des cellules est superieure à 14 et 17 jours.
UPTAKE AND RELEASE OF D‐ AND L‐ASPARTATE BY RAT BRAIN SLICES
Authors: Davies L. P. , Johnston G. A. R.
Published: October 2006

Abstract—

D‐Aspartate is accumulated by slices of adult rat cortex by a high affinity uptake which is abolished if the sodium ions in the incubation medium are replaced by choline. A small uptake of D‐aspartate takes place if the sodium ions are replaced by lithium ions. It appears likely that D‐aspartate shares the same transport system with L‐aspartate, and that the uptake of D‐aspartate is into the same osmotically‐sensitive particles as those which accumulate L‐aspartate. D‐Aspartate is released from cerebral cortex slices by raised potassium concentrations, provided calcium is present in the perfusing buffer.

Both D‐ and L‐aspartate produce gross hyperactivity when injected intraperitoneally into immature rats.

Radioactive D‐aspartate may be very useful in examining the neurotransmitter role of the naturally‐ occurring L‐aspartate e.g. in studies of the autoradiographic localization of high affinity L‐aspartate accumulation, its main advantage being that, unlike L‐aspartate, D‐aspartate does not undergo rapid metabolism.
GANGLTOSIDES AND THE ARCHITECTURE OF HUMAN FRONTAL AND RAT SOMATOSENSORY ISOCORTEX
Authors: Hess Helek H. , Bass N. H. , Thalhhmer Carol , Devarakonda Rita
Published: October 2006

Ganglioside sialic acid was determined in the layers of human frontal association cortex and rat somatosensory cortex by microchemical methods of sampling and analysis. In both cortices the distribution per unit dry weight showed three main peaks or inflections: (1) at the junction of layers II and III; (2) in the lower part of layer III at the junction with IV; and (3) at the junction of layers V and VI. These distributions parallel the occurrence of high concentrations of dendritic and axonal plexuses and their synaptic articulations. In human cortex, the concentration of ganglioside sialic acid per unit dry weight was slightly greater, the amount per cell was twice as great. and the amount per neuron present was 2‐ to 6‐fold greater than in rat somatosensory cortex. The ganglioside sialic acid per cell was 120‐ to 200‐fold greater in human association cortex than in rat retina, which is a CNS region with sparse neuropil. The results support the validity of ganglioside sialic acid as an index of the relative mass of neuronal plasma membranes in neural tissues and its usefulness in chemoanatomic quantitation of axodendritic interrelationships established by synaptic contacts with local and distant neurons.
SUBSTRATE AND INHIBITOR‐RELATED CHARACTERISTICS OF MONOAMINE OXIDASE IN C6 RAT GLIAL CELLS
Authors: Murphy D. L. , Donnelly Cynthia H. , Richelson E.
Published: October 2006

Cultured C6 rat glial cells preferentially deaminated 5‐hydroxytryptamine, tryptamine, dopamine and tyramine in comparison to phenylethylamine and benzylamine. Deamination of all substrates was uniformly sensitive to inhibition by clorgyline and relatively insensitive to deprenyl. These data together with the observations of simple sigmoid curves for the inhibition of tyramine deamination by both inhibitors suggest that C6 glial cells contain mainly monoamine oxidase type A, which previously had been suggested to be primarily an intraneuronal MAO type. As these findings are in agreement with other studies of brain MA0 activity in mitochondria separated from neuronal vs glial cell preparations, they help explain why MA0 activity measured with some substrates may be little affected by lesions or by drugs producing nerve ending degeneration.
A COMPARISON OF AXONALLY TRANSPORTED PROTEINS IN THE RAT SCIATIC NERVE BY IN VITRO AND IN VIVO TECHNIQUES
Authors: THEILER R. F. , MCLURE W. O.
Published: October 2006

Abstract—

An in vitro system for studying fast axonal transport in mammalian nerves has been developed. The viability of in vitro nerve preparations was established on the basis of three criteria: electron microscopy, electrical properties, and the activities of two marker enzymes, 5'‐nucleotidase and total ATPase. The specific activity of transported proteins was greater using the in vitro procedure, and the level of locally incorporated radioactivity lower, when compared to in vivo transport experiments. Separation of solubilized transported proteins on polyacrylamide gels in the presence of sodium dodecyl sulfate showed that a large number of polypeptides are transported. Using a double label procedure which employed L‐[3H]methionine and L‐[35S]methionine, proteins transported in vitro and in vivo were compared. No differences in the electrophoretic distribution of transported proteins from the two systems was seen. The major component of transported proteins electrophoresed with an apparent molecular weight of 105,000 ± 24,000. Using the in vitro system, transported proteins were compared to those labelled locally in either Schwann cells or cells of the dorsal root ganglion. Large differences in the labelling patterns were observed in both comparisons. We conclude that in vitro procedures provide a valid means of studying rapid axoplasmic transport. The proteins carried by rapid axoplasmic transport differ from those synthesized in either the Schwann cells of the sciatic nerve or the cells of the dorsal root ganglion.
THE CHARACTERIZATION OF HISTIDINE DECARBOXYLASE AND ITS DISTRIBUTION IN NERVES, GANGLIA AND IN SINGLE NEURONAL CELL BODIES FROM THE CNS OF APLYSIA CALIFORNICA
Authors: WEINREICH D. , Yu Y.‐T.
Published: October 2006

Abstract—

Histamine (HA) is present in substantial quantities in all ganglia of Aplysia californica. Within the cerebral ganglia this amine is known to be concentrated in at least two identified neurons designated C‐2 neurons. In this study a combination of chemical and enzymatic analyses was employed to provide evidence for the existence of a biochemical pathway for HA synthesis in ganglia and individual neurons of this marine mollusk. Examination of extracts of individual neurons dissected from ganglia organ‐cultured in the presence of [3H]histidine showed that every neuron accumulated labelled histidine, but only the HA‐containing C‐2 neurons synthesized and stored labelled HA suggesting that the formation of HA in Aplysia could be catalyzed by the enzyme histidine decarboxylase (HDC). HDC activity was studied with a new microradiometric assay. Many of the properties of the molluscan HDC studied were found to correspond to the vertebrate enzyme. Enzyme activity was inhibited by α‐hydrazino‐histidine but unaffected by concentrations of α‐methyldopa or by 5‐(3,4‐dihydroxycinnamoyl) salicylic acid which produced nearly complete inhibition of aromatic amino acid decarboxylase activity. HDC was measurable in nervous but not other Aplysia tissues assayed. All 5 major ganglia contained HDC activity which spanned a 15‐fold range between the least and most active ganglia. Only 4 of the 13 nerve trunks assayed yielded measurable enzymic activity; these active nerves were associated with the cerebral ganglia which has the highest HDC activity of all measured ganglia. Of the numerous individual neurons assayed for HDC, only the C‐2 cells showed measurable enzyme activity, about 25 pmol/cell/h or 70 μmol/g protein/h. Since the activity of HDC in the HA‐containing neurons was at least three orders of magnitude larger than all other neurons assayed in the cerebral and other ganglia, these data appear to provide a direct metabolic basis for the selective presence of HA in these cells, and they indicate that the cellular presence of HDC provides a useful biochemical marker for the location of HA‐rich neurons in Aplysia.
CYCLIC GMP IN A NEUROBLASTOMA CLONE: POSSIBLE INVOLVEMENT IN MORPHOLOGICAL DIFFERENTIATION INDUCED BY DIBUTYRYL CYCLIC AMP
Authors: Zwiller J. , Goridis C. , Ciesielski‐Treska J. , Mandel P.
Published: October 2006

Abstract— DBcAMP induces morphological differentiation of mouse neuroblastoma cells grown in culture. DBcGMP or 8‐Br cyclic GMP when added alone also induces a discrete morphological differentiation. When analogues of cyclic GMP were added together with dBcAMP, neurite outgrowth was strikingly enhanced as compared to the effect of dBcAMP alone. Intracellular concentrations of cyclic GMP were increased during dBcAMP treatment and cyclic AMP levels were increased during 8‐Br cyclic GMP treatment. Both treatments produced an increased protein kinase activity, supporting the possibility that not only cyclic AMP but also cyclic GMP may be involved in the differentiation process.
COMPARISON OF THE ISOELECTRIC AND MOLECULAR WEIGHT PROPERTIES OF TUBULIN SUBUNITS
Authors: Feit H. , Neudeck Ursula , Baskin F.
Published: October 2006

Abstract— Brain tubulin subunits were separated by a combination of isoelectric focusing and electrophoresis in the presence of sodium dodecyl sulfate (SDS) using a two‐dimensional polyacrylamide slab gel technique. Isoelectric focusing separated tubulin subunits into two major groups of bands, such that the more acidic group corresponded to the α subunit and the less acidic group corresponded to the β subunit. In addition, isoelectric focusing resolved the β subunit into two subspecies which differed slightly in isoelectric properties but were the same apparent molecular weight. The a subunit was resolved into many subspecies that appear to differ from each other by both apparent molecular weight and isoelectric properties.