bluuebunny/crossref_metadata_2025 huggingface dataset:
FURTHER STUDIES OF THE TRANSPORT OF PROTEIN TO NERVE ENDINGS*
Authors: Barondes S. H.
Published: October 2006

Mice were injected intracerebrally with [l‐14C]leucine, and the specific activities of subcellular fractions of brain and effractions of isolated nerve endings were determined. There was a progressive increase in the specific activity of protein associated with isolated nerve endings after incorporation of [l‐14C]leucine into whole brain protein had terminated. Although, the incorporation of [14C]leucine into soluble protein of whole brain did not differ significantly in mice which were 3 months or 1‐year old, the subsequent increase in specific activity of soluble protein isolated from nerve endings was significantly greater in the younger animals; 6‐month‐old mice were intermediate. Therefore, changes in some aspect of the transport of protein to nerve endings is altered even after sexual maturity.

Anaesthetization with pentobarbitone during incorporation of [14C]leucine into protein, and inhibition of protein synthesis with acetoxycycloheximide after incorporation of [14C]leucine was complete, did not interfere with the subsequent appearance of radioactive protein at the nerve ending.

Evidence is presented for the transport, from a proximal site of synthesis, of protein associated with particulate components of the nerve ending, including synaptic vesicles.
HISTOCHEMICAL MAPPING OF LACTATE DEHYDROGENASE AND MONOAMINE OXIDASE IN THEMEDULLA OBLONGATA AND CEREBELLUM OF SQUIRREL MONKEY (SAIMIRI SCIUREUS)
Authors: Manocha Sohan L. , Bourne Geoffrey H.
Published: October 2006

Abstract— —The gross distribution of LDH and MAO was studied in a caudo‐cranial series of 50 μ thick sections through the medulla oblongata and cerebellum. In general, LDH exhibited a stronger reaction in the neuropil and in the perikarya, whereas MAO showed moderate activity in the neurons and mild to moderate activity in the neuropil. The axonal processes and nerve fibres showed comparatively stronger MAO activity. The nuclei gracilis, cuneatus medialis and lateralis, cranial nerve nuclei, olivaris inferior, vestibularis and cochlearis nuclei showed particularly strong LDH and equally weak MAO activities. The lateral part of the formato reticularis myelencephali showed much more MAO than did the medial part, whereas the LDH reaction was uniformly strong. The reticularis lateralis showed uniformly strong LDH and very mild MAO activities.

In the cerebellar cortex, the MAO activity was concentrated in the molecular layer and nerve fibre layer, whereas LDH activity was particularly strong in the Purkinje cells and their processes in the molecular layer. The cerebellar nuclei showed strong LDH and weak MAO in the neutrons and stronger MAO and moderate LDH in the neuropil.
THE EFFECT OF PHENYLPYRUVATE ON OXIDATIVE‐PHOSPHORYLATION IN BRAIN MITOCHONDRIA1
Authors: Gallagher B. B.
Published: October 2006

Abstract— A mitochondrial fraction isolated from the cerebral cortex of immature rats was shown to possess the characteristics of intact, functional mitochondria. Phenylpyruvate, in low concentrations, had an inhibitory effect upon oxygen utilization by this system without uncoupling phosphorylation. The inhibition was specific for the keto acid and to pyruvate as substrate. It was concluded that phenylpyruvate inhibits the oxidation of pyruvate and the implications of this are discussed in relation to phenylpyruvic oligophrenia.
RELEASE OF [3H]SEROTONIN FROM BRAIN SLICES1
Authors: Chase T. N. , Katz R. I. , Kopin I. J.
Published: October 2006

Abstract—

1. Labelled serotonin ([3H]5‐HT) accumulated by slices of rat brain either in vivo or in vitro is released by depolarizing procedures such as electrical stimulation or high external potassium concentrations. Electrical stimulation predominantly affects the liberation of the unchanged amine, rather than of its principal metabolite, 5‐HIAA.

2. Release of [3H]5‐HT does not appear to be calcium‐dependent.

3. Amount of release parallels the density of serotonin‐containing nerve terminals in each of several cerebral regions tested. Release from several extracerebral tissues was similar to that obtained from cerebral tissues having relatively little endogenous 5‐HT.

4. Electrically induced release of [3H]5‐HT is markedly inhibited by desipramine, chlorpromazine, LSD, lithium and ouabain.
SYNTHESIS OF RNA IN NEURONS OF THE HYPOGLOSSAL NERVE NUCLEUS, AFTER SECTION OF THE AXON, IN MICE
Authors: Haddad A. , Iucif Sálua , Cruz A. R.
Published: October 2006

Abstract—

Synthesis of RNA in neurons of the hypoglossal nerve nucleus after axonal section was studied by means of [5‐3H]uridine administration and radioautographic counting techniques in mice. The results of the experiments were evaluated by counts of silver grains over the nucleoplasm and cytoplasm of the neurons. RNA synthesis was greater in neurons after axonal section, and this increase was evident from 12 hr after the operation. The greatest increases in the operated side were observed in the 1st, 2nd and 3rd days after operation. In the 7th and 14th days RNA synthesis was still greater in the hypoglossal nucleus of the sectioned nerve but the difference in the control nucleus was not so striking. In the 30th day synthesis of RNA in left and right hypoglossal nuclei was comparable.
THE BIOSYNTHESIS OF TRIPHOSPHOINOSITIDE BY PURIFIED MYELIN OF PERIPHERAL NERVE
Authors: Iacobelli S.
Published: October 2006

Abstract—

The distribution of diphosphoinositide kinase activity in homogenates and myelin of rabbit nerve was determined by measuring the synthesis of labelled triphosphoinositide. Evidence is presented to show that the biosynthesis of triphosphoinositide in peripheral myelin involves a membrane‐bound diphosphoinositide kinase.
AN ISOTOPIC MICROMETHOD FOR THE MEASUREMENT OF CHOLINESTERASE ACTIVITY IN INDIVIDUAL CELLS
Authors: Koslow S. H. , Giacobini E.
Published: October 2006

—A microisotopic method for measuring acetylcholinesterase activity in isolated cells is described. The assay employs [14C]acetylcholine and can measure 7 × 10‐12 moles of acetylcholine hydrolysed/hr in 50‐150 samples per experiment.

The method described has been applied to the measurement of cholinesterase activity in individual sympathetic ganglion cells of the cat. It has been shown that under standard conditions the substrate has complete access to the enzymatic site.
ISOLATION AND CHARACTERIZATION OF GLYCOSAMINOGLYCANS IN PERIPHERAL NERVE AND SPINAL CORD OF MONKEY
Authors: Chandrasekaran E. V. , Bachhawat B. K.
Published: October 2006

—The isolation of uronic acid‐containing glycosaminoglycans from peripheral nerve and spinal cord of monkey was done by combining the cetyl pyridinium procedure and DEAE‐Sephadex column chromatography. The constituent analyses of the isolated GAG‐fractions indicated that hyaluronic acid, chondroitin‐4‐sulphate, chondroitin‐6‐sulphate, heparan sulphate and a testicular hyaluronidase‐resistant galactosamine‐containing GAG were present in both tissues. Hyaluronic acid was the predominant GAG (63 per cent) in both tissues and its level was much higher than in brain. Chondroitin‐4‐sulphate constituted 16 per cent in both tissues. The levels of heparan sulphate and hyaluronidase‐resistant galactosamine‐containing GAG in these tissues were much lower than in brain. The results indicate that the patterns of GAGs in peripheral nerve and spinal cord of monkey are similar but differ from that of brain.
INCREASE OF GLUCOSE AND HIGH ENERGY PHOSPHATE RESERVE IN THE BRAIN AFTER HYDROCORTISONE1
Authors: Thurston Jean Holowach , Pierce R. Wendell
Published: October 2006

Abstract— Young mice treated with hydrocortisone (50 mg/kg) subcutaneously for 10 days showed a doubling of brain glucose. Brain phospho‐creatine, glucose‐6‐phosphate, and ATP increased slightly. Brain glycogen and lactate were unchanged. Total energy reserve of the brain was 23 per cent higher than the control value. Liver glycogen was increased 47 per cent; liver and blood glucose levels were 11 per cent lower than in control animals. Since the animals showed no evidence of sedation, these findings suggest a facilitated transport of glucose from blood into the brain under the influence of hydrocortisone. Other possible explanations include an inhibition of the hexose monophosphate shunt and a proportionate decrease in both the oxidative and glycolytic pathways of the brain, but it was concluded that these explanations are less likely.
POLYAMINES and NUCLEIC ACID METABOLISM DURING DEVELOPMENT OF CHICK EMBRYO BRAIN
Authors: Caldarera C. M. , Moruzzi M. S. , Rossoni C. , Barbiroli B.
Published: October 2006

Abstract— Spermine and spermidine reach maximum concentrations in the chick embryo brain between the 12th and 14th day of incubation. Sucrose‐density‐gradient analysis of polyribosome distribution in the developing chick embryo brain, showed the presence of polyribosomal aggregates in the regions of 147 S and 206 S between the sixth and eighth day of incubation. After the 16th day of incubation the presence of heavier polyribosomal aggregates in the region of 259 S and 280 S was found. The injection of spermine or spermidine into the air space of embryos on the tenth day of incubation leads to a remarkable increase in the incorporation rate of [3H]formate into the ribosomes. Studies under similar experimental conditions, showed an increased radioactivity in the region of 147 S, 206 S, 259 S and 280 S in embryos injected with spermine or spermidine.
α‐(γ‐AMINOBUTYRYL)‐LYSINE IN MAMMALIAN BRAIN: ITS IDENTIFICATION AND DISTRIBUTION
Authors: Nakajima T. , Kakimoto Y. , Kumon A. , Matsuoka M. , Sano I.
Published: October 2006

Abstract— α‐(γ‐Aminobutyryi)‐lysine was identified in rabbit brain. This compound was detected exclusively in the brain of mammals, but not in other tissues. It is not concentrated in any particular region of the rabbit brain.
PURIFICATION AND CHARACTERISTICS OF RNase INHIBITOR FROM PIG CEREBRAL CORTEX
Authors: Takahashi Y , Mase K , Suzuki Y
Published: October 2006

Abstract— An RNase inhibitor has been purified from pig cerebral cortex by DEAE‐cellulose and hydroxylapatite chromatography and Sephadex G‐100 gel filtration. The purified RNase inhibitor could be resolved into a major band (about 80–85 per cent of total protein) and several minor components by polyacrylamide gel electrophoresis.

The ultraviolet absorption curve of the purified RNase inhibitor indicated a typical protein spectrum. The inhibitor was inactivated by digestion with trypsin or prozyme, and by heating at 70ºC for 5 min. The inhibitor was also inactivated by an SH reagent such as p‐chloromercuribenzoate. The inhibitor did not affect RNase T1. It has been suggested that the inhibitor is an acidic protein and also a SH‐protein. The molecular weight of the RNase inhibitor was estimated to be about 60,000.
FRACTIONNEMENT DE L'ORGANE ELECTRIQUE DE LA TORPILLE: LOCALISATION SUBCELLULAIRE DE L'ACETYLCHOLINE SUBCELLULAR FRACTIONATION OF THE ELECTRIC ORGAN OF TORPEDO MARMORATA
Authors: Israël M , Gautron J , Lesbats B
Published: October 2006

Résumé— L'acètylcholine a été localisée au niveau d'une fraction de vésicules synaptiques isolée à partir de l'organe électrique; le taux d'acétylcholine est fonction de la pression osmotique du milieu. La choline‐acétyltransfèrase (EC 2.3.1.6) n'est pas associée à cette fraction. Les distributions sont comparées à celles de diverses enzymes.

—The electric organ of Torpedo is a purely cholinergic tissue from which fractions of small vesicles 800 Å in diameter may be isolated by homogenisation and centrifugation. The vesicle fraction is rich in acetylcholine. The yield of acetylcholine in the vesicle fraction is dependent on the osmolarity of the homogenisation medium, 800 mosm being optimal. The isolated vesicles themselves lose acetylcholine when subjected to hypo‐osmotic conditions. Choline acetyltransferase (EC 2.3.1.6) behaves as a cytoplasmic enzyme and is not associated with the vesicular fraction. Acetylcholinesterase (EC 3.1.1.7) is found in fractions containing membrane fragments. The cellular distribution of these components of the cholinergic synapse is similar in Torpedo electric organ and mammalian cortex.
THE METABOLISM IN VIVO OF GLYCINE AND SERINE IN EIGHT AREAS OF THE RAT CENTRAL NERVOUS SYSTEM1
Authors: Shank R. P , Aprison M. H
Published: October 2006

Abstract— Results of studies designed to estimate the rates at which glycine is derived from various possible sources in discrete areas of the rat CNS are reported. These results suggest that glycine is derived predominantly by de novo synthesis, presumably via the established pathways leading from glucose through serine to glycine. The content of glycine ranged from a low of approximately 0‐6 μmol/g in the cerebellum and telencephalon to a high of 5·5 μmol/g in the spinal cord grey matter; however, based on its estimated rate of synthesis from serine, there appeared to be no correlation between the content of glycine and its rate of synthesis in the various areas studied. The flux of glycine from blood into the CNS was slower (0·03‐0·15 μmol/g/h depending on the CNS structure) than that of serine (0·15‐0·23 μmol/g/h) and both amino acids entered various CNS areas at rates unrelated to their respective tissue contents. These data have been discussed with regard to the putative transmitter function of glycine in the spinal cord and brainstem.
WALLERIAN DEGENERATION IN RABBIT OPTIC NERVE: CELLULAR LOCALIZATION IN THE CENTRAL NERVOUS SYSTEM OF THE S‐100 AND 14‐3‐2 PROTEINS1
Authors: Perez V. J , Olney J. W , Cicero T. J , Moore B. W , Bahn B. A
Published: October 2006

Abstract— The S‐100 and 14‐3‐2 proteins, which are found only in nervous tissues, were measured in degenerating rabbit optic nerve at 0, 5 10, 20, 40, 60, 80, 100, 150 and 200 days after unilateral enucleation in order to obtain indications of the cellular localization of these proteins in the central nervous system. S‐100 increased and 14‐3‐2 decreased (both approximately 70 per cent) in cut nerves by 200 days of degeneration. Changes in amounts of the proteins were related to cellular alterations which characterize the degenerative process, as demonstrated by electron microscopy. In uncut nerves (intact eye) from these experimental animals, S‐100 increased and 14‐3‐2 decreased slightly at 5 days, after which time the levels of each returned to those approximating the content in corresponding nerves from unoperated control animals. No appreciable change in total soluble proteins was measured in degenerating or intact nerves. Since S‐100 increased and 14‐3‐2 decreased in the degenerating optic nerve as it became relatively enriched in glial constituents but impoverished in axonal content, it is suggested that S‐100 is primarily a glial protein and 14‐3‐2 predominantly a neuronal protein in the central nervous system.
PHOSPHOLIPID COMPOSITION OF SOME PARTS OF RAT HYPOTHALAMUS, AND ITS RELATION WITH SOME HISTOCHEMICAL OBSERVATIONS1
Authors: Roozemond R. C.
Published: October 2006

—In continuation of a histochemical investigation of phospholipids in rat brain, the content and composition of these lipids in some regions of rat hypothalamus were examined using ultra‐micromethods. The supraoptic and paraventricular nuclei, the anterior area of the hypothalamus, and the adjacent optic chiasma were chosen for this study. The phospholipid content of all of these regions was found to be almost equally high. Proportionally higher amounts were found for phosphatidylethanolamine in the optic chiasma and for phosphatidylcholine in the neurosecretory nuclei. In all regions investigated the sphingomyelin content was nearly the same. From these results it was concluded that the large differences in staining properties of myelinated and unmyelinated areas of the tissue when applying Baker's acid haematein test could not be ascribed to large differences in the content of the Baker‐positive, choline‐containing, phospholipids. Treatment of fixed tissue with cold acetone in order to extract non‐polar lipids that may mask phospholipids, did not abolish the staining differences.

The possible involvement of cerebrosides and proteolipids mainly found in myelinated tissue in the Baker reaction is discussed. It is suggested that the differences in staining properties might be ascribed to differences in structure of myelinated and unmyelinated tissue, rather than to differences in the content of Baker‐positive lipids.
CEREBRAL LIPIDS IN A CASE OF SYSTEMIC GM2‐GANGLIOSIDOSIS OF A LATE INFANTILE TYPE1
Authors: Klibansky Chaya , Saifer A. , Feldman N. I. , Schneck L. , Volk B. W.
Published: October 2006

—Quantitative analyses performed on the lipids of cerebral grey matter from brains of a normal child and a child with Tay‐Sachs (T‐S) disease were compared with such analyses on the brain of a 6‐year‐old, non‐Jewish male with systemic GM2‐gangliosidosis of a late infantile type (GM2‐LI). Analysis of gangliosides showed a 3·5‐fold increase of total gangliosides in the GM2‐LI brain and a six‐fold increase in the T‐S brain, compared to normal brain. Both pathological brains had similar distribution patterns for gangliosides, with the GM2‐ganglioside component constituting more than 80 per cent of the total. Lipid components in the T‐S brain were below normal values except for lecithin and cholesterol, while in the GM2‐LI brain there were increases in sulphatides, cerebrosides, sphingomyelin and cholesterol. Approximately twice as much ceramide trihexoside was present in the T‐S brain as in the GM2‐LI brain, and none could be detected in the normal brain. The clinical, pathological and biochemical data support the conclusion that this case represents a new variant of systemic late‐infantile gangliosidosis in which there is an accumulation of the GM2‐ganglioside like that in Tay‐Sachs disease.
THYMIDINE METABOLISM AND DEOXYRIBONUCLEIC ACID SYNTHESIS IN THE DEVELOPING RAT BRAIN
Authors: Mori K. , Yamagami S. , Kawakita Y.
Published: October 2006

—In growing rat brain, the specific activity of DNA at 12 h after the subcutaneous injection of [3H]thymidine underwent a sharp rise during the first 6 days of life, dropping just as precipitously by 15 days, thereafter continuing to decrease with increasing age.

When [3H]thymidine was given to 6‐day‐old rats, a considerable amount was taken up immediately into the brain. Thymidine taken up into the acid‐soluble fraction was readily phosphorylated to its nucleotides, thymidine mono‐, di‐, and triphosphate (TMP, TDP and TTP) within only 30 min following injection. The highest specific activity was found in TTP. The incorporation of of [3H]thymidine into DNA took place over a longer period of time after injection.
THE EFFECT OF MORPHINE ON THE TRANSPORT AND METABOLISM OF INTRACISTERNALLY‐INJECTED LEUCINE IN THE RAT
Authors: Clouet Doris H. , Neidle A.
Published: October 2006

—Intracisternally injected l or d‐[14C]leucine was retained longer in the brains of morphine‐treated rats than in saline‐injected control animals. This resulted in higher levels of the labelled leucine and of labelled metabolites of the l‐isomer in free pools of brain tissue. However, the absolute levels of brain amino acids and the relative distribution of radioactivity among l‐leucine metabolites in brain were unaffected by treatment with morphine, indicating that no disturbance of leucine oxidation through the citric acid cycle was produced by the drug. The inhibition of protein synthesis caused by acute administration of morphine was calculated to be greater than previously reported since morphine treatment increased the specific radioactivity of the free pool of leucine in brain following the intracisternal injection of the labelled amino acid. Possible mechanisms responsible for these morphine effects are discussed.
SURFACE CHARGE OF CHOLINE ACETYLTRANSFERASE FROM DIFFERENT SPECIES
Authors: Fonnum F.
Published: October 2006

—The adsorption of partially purified choline acetyltransferase (ChAc) from cat, rat, guinea‐pig and pigeon brains by the cation exchange resins, CM‐Sephadex (C‐50) and Amberlite CG‐50 II, was studied at various pH values and ionic strengths. ChAc from cat and rat were more strongly adsorbed by cation exchangers and therefore have a stronger net positive surface charge than those from guinea pig and pigeon. Experiments showed that the difference in adsorption between these two groups of enzymes could not be explained by overloading of the resin, by competitive effect of other proteins present in the enzyme preparations or by the presence of any component suppressing the adsorption of ChAc in any of the enzyme preparations. The adsorption of ChAc by a cation exchanger is very similar to its binding to synaptosome membranes. The significance of the positive surface charge of ChAc in studies on the compartmentation of ChAc in synaptosomes is discussed.
RESERPINE‐LIKE ACTION OF CHLORPROMAZINE ON RABBIT BASAL GANGLIA
Authors: Tagliamonte A. , Tagliamonte P. , Gessa G. L.
Published: October 2006

Abstract— In rabbits, the sedative effect of chlorpromazine (CPZ) is temporally correlated with a decrease in dopamine and a rise in homovanillic acid (HVA) in the basal ganglia. Reserpine elicits similar biochemical changes. In addition, both reserpine and CPZ reduce the concentration of 3‐methoxytyramine, the O‐methylated metabolite of dopamine in the basal ganglia of normal rabbits. In contrast, both drugs markedly increase the levels of this metabolite in animals treated with a monpamine oxidase inhibitor. The results indicate that CPZ, like reserpine, causes an intraneuronal destruction of dopamine, and suggest that the well‐documented increase in dopamine synthesis after CPZ is the consequence of this mechanism and not of a blockade by CPZ of the dopaminergic receptors in brain.
EFFECTS OF HYPOPHYSECTOMY ON RNA METABOLISM IN RAT BRAIN STEM
Authors: Gispen W. H. , Wied D. De , Schotman P. , Jansz H. S.
Published: October 2006

Abstract— Ribosomal aggregates were isolated from rat brain stem and characterized as polysomes by sedimentation analysis and by their sensitivity to RNase and EDTA treatment.

Three weeks following hypophysectomy there was a significant decrease in the content of large polysomes in the rat brain stem. The incorporation of radioactive uridine into RNA was studied using a double‐labelling technique with [3H]‐ and [14C]uridine and labelling periods of 70 and 180 min. It was found that after hypophysectomy the incorporation of radioactive uridine into total, nuclear and cytoplasmic RNA and in polysomes was decreased after 70 and 180 min. Information on the nature of the rapidly‐labelled RNA in the various subcellular fractions was obtained by sucrose gradient sedimentation analysis.

After 70 min of labelling the nucleus contained heterogeneous RNA with a considerable fraction of RNA sedimenting faster than 28 S. In the cytoplasmic fraction heterogeneous 4 to 30 S RNA was found, presumably associated with RNP particles, whereas after 180 min the polyribosomal aggregates were also labelled.

The present results indicate a profound effect of hypophysectomy on the metabolism of all species of brain RNA investigated.
SIALOGLYCOPROTEINS AND SEVERAL GLYCOSIDASES IN DEVELOPING RAT BRAIN
Authors: Quarles R. H. , Brady R. O.
Published: October 2006

Abstract— The amount of sialoglycoproteins expressed as μmol of sialic acid per g of lipid‐free residue remained fairly constant in developing rat brain. However, the activity of various enzymes which may be involved in glycoprotein metabolism varied in an inconstant fashion during the period of development. The specific activity of a neuraminidase increased, N‐acetyl‐β‐glucosaminidase remained relatively constant, while the specific activities of α‐mannosidase and α‐fucosidase decreased.
CHOLESTEROL ESTERS AND HYDROLYTIC CHOLESTEROL ESTERASE DURING WALLERIAN DEGENERATION1
Authors: Mezei Catherine
Published: October 2006

Abstract—

To study the involvement of cholesterol esters in myelination and demyelination, we determined the concentration of free cholesterol and cholesterol esters and the activity of hydrolytic cholesterol esterase (sterol ester hydrolase; EC 3.1.1.13) in hen sciatic nerve during Wallerian degeneration. A progressive increase in the ratio of cholesterol ester to free cholesterol was observed in the degenerating nerve at 8, 16 and 32 days after nerve section. Hydrolytic cholesterol esterase activity decreased progressively in the degenerating nerves at the same time.

In addition we measured the ratio of RNA to DNA, and the activity of the NADP+‐dependent isocitrate dehydrogenase [L8‐isocitrate: NADP oxidoreductase (decarboxylating); EC 1.1.1.42] at 8, 16 and 32 days after nerve section. The RNA to DNA ratios decreased progressively in the degenerating nerves. NADP+‐dependent isocitrate dehydrogenase increased in activity after nerve section, reaching a peak at 16 days.
DEVELOPMENTAL CHANGES OF CHOLINESTERASES AND MONOAMINE OXIDASE IN CHICK EMBRYO SPINAL AND SYMPATHETIC GANGLIA
Authors: Giacobini G. , Marchisio P. C. , Giacobini E. , Koslow S. H.
Published: October 2006

Abstract— Total cholinesterase, acetylcholinesterase, (AChE) and monoamine oxidase (MAO) activity and protein content were determined throughout the embryonic life of the chick in spinal and sympathetic ganglia. The greatest part of total cholinesterase activity was due to AChE.

AChE and MAO activity increased in both spinal and sympathetic ganglia very similarly from the 6th to the 12th day of incubation; from this day on a significant divergence occurred, mainly owing to a steady fall in spinal ganglion AChE, which decreased to approximately one tenth of the maximum value. The ratio of MAO activity in sympathetic and spinal ganglia increased from the 8th day onwards and approached 5·0 at hatching. The ratio between sympathetic and spinal ganglia, for AChE, choline acetylase (ChAc) and MAO activity, suggests a relationship between the maturation of the synapse in the sympathetic ganglia and the maximal activity of these enzymes.
COMPOSITION OF CEREBRAL LIPIDS IN MURINE LEUCODYSTROPHY: THE QUAKING MUTANT
Authors: Hogan E. L. , Joseph K. C.
Published: October 2006

Abstract—

The composition of sphingolipids and phospholipids of mouse brain during myelination was determined in the Quaking mutant, which manifests a genetic disorder of myelin formation, and in littermate controls. The biochemical changes during myelination in the brains of the controls corresponded quantitatively with previous findings in a different strain of mice. The Quaking mutant exhibited concentrations of sphingolipids and phospholipids in brain which were comparable to those of controls in the early stage of myelination but the tissue content failed to increase with maturation. The greatest differences occurred in the cerebrosides which at 65 days of postnatal age were only 10 per cent of control levels. During development the pattern of cerebral levels of sphingomyelin, plasmalogen and total phospholipid in the mutants tended to resemble that of the cerebrosides.

The defect in the Quaking mutant is compatible with a failure in maturation of myelin. These findings have been compared with those in the Jimpy mutant, a different genetic disorder of myelin in the mouse previously studied in a similar fashion. The Jimpy mutant is characterized by a quantitatively more pronounced deficiency of myelin lipids and a decline in cerebrosides during brain development.
DIFFERENTIAL METABOLISM OF RNA IN NEURONAL‐ENRICHED AND GLIAL‐ENRICHED FRACTIONS OF RAT CEREBRUM
Authors: Flangas A. L. , Bowman R. E.
Published: October 2006

Abstract—

Cerebral tissue of rat, disrupted by passage through a custom‐designed tissue press, was diluted to a 10% (w/v) cellular suspension in 10% (w/v) Ficoll and was then fractionated in the Spinco Model L ultracentrifuge into: (1) two enriched cellular layers (alpha and beta) in an isopycnic Ficoll gradient in the Spinco 40 angular rotor; or (2) into four layers (A, B, C, and D) in a discontinuous Ficoll gradient in the Spinco SW 39 swinging bucket rotor. The cellular composition of these layers was identified microscopically and enzymically as either glial‐enriched (alpha and B layers) or neuronal‐enriched (beta and C layers) fractions of cerebral cortex. Portions of the neuronal and glial fractions were used for determinations of total nitrogen, and for colorimetric determinations of carbonic anhydrase activity (a glial cell marker). These data established that glial contamination of the neuronal‐enriched layer averaged 6·5 per cent. The data also indicated glial enrichment of Layer B, although no quantitative assessment of the amount of neuronal contamination was possible.

The kinetics of metabolism of RNA in the glial‐enriched and neuronal‐enriched fractions were studied from 0·5 to 16 h after‐intracisternal injection of either [3H]cytidine or [3H]orotic acid. In addition, the incorporation of [3H]cytidine into crude nuclear and cytoplasmic components of the layers was studied by the use of 1 h pulses. Our findings indicated greater incorporation of [3H]cytidine into nuclear fractions than into cytoplasmic fractions at 1 h and greater incorporation of both precursors into neuronal‐enriched fractions than into glial‐enriched fractions at all pulse times.
THE INCORPORATION OF [14C]LYSINE INTO THE PROTEIN OF THE GUINEA PIG CENTRAL AUDITORY SYSTEM1
Authors: Davies W. E.
Published: October 2006

Abstract—

The incorporation of [14C]lysine into various brain proteins was studied. The proteins of different areas of the auditory system and cortical subcellular fractions were analysed using a disc electrophoretic technique that allows both protein and radioactivity assays along the gels. The highest level of incorporation was found in the mid brain nuclei, particularly the inferior colliculus, and was lowest in the auditory cortex proteins. This was true for both saline soluble proteins and proteins solubilized by Triton X‐100 treatment. Of the subcellular fractions, the highest level of activity was found in the microsomal fraction. Considerable radioactivity was also found in the proteins isolated from the synaptosome‐rich fraction. Of particular interest in this fraction was a slow migrating protein band which was soluble in Triton X‐100, had a high specific activity, and appeared to be synaptosome specific. These observations are in concurrence with the hypothesis that the nerve ending contains protein synthesizing machinery.
EFFECTS OF COLCHICINE ON AXONAL TRANSPORT IN PERIPHERAL NERVES
Authors: Sjöstrand J. , Frizell M. , Hasselgren P.‐O.
Published: October 2006

—Colchicine injected intracisternally markedly inhibited the rapid migration (300‐400 mm/day) of labelled proteins in the hypoglossal and vagus nerve of the rabbit. The transport of acetylcholinesterase (EC 3.1.1.7) and choline acetyltransferase (EC 2.3.1.6) previously shown to move with the slow (5‐26 mm/day) phase of axoplasmic transport in these nerves, was only partially blocked. In view of this differential effect on axonal flow, we suggest that the neurotubules, on which colchicine acts preferentially, are primarily involved in the rapid (300‐400 mm/day) axoplasmic flow. After local injection of colchicine into the nerves both the rapidly migrating labelled proteins and the enzymes (AChE and ChAc) accumulated above the site of injection to the same degree as they accumulate above a nerve ligation. Since this blockage of enzyme transport occurred after concentrations of colchicine much higher than those used for intracisternal injections these findings after local injection may represent more severe effects on axonal transport systems.
REDUCTION OF LEVEL OF L‐GLUTAMIC ACID DECARBOXYLASE BY γ‐AMINOBUTYRIC ACID IN MOUSE BRAIN1
Authors: Sze P. Y. , Lovell R. A.
Published: October 2006

Abstract— The effects of accumulated endogenous GABA on the activity of L‐glutamic acid decarboxylase (GAD) were studied in mouse brain. When the content of GABA in the brain was increased after administration in vivo of aminooxyacetic acid (AOAA), there was a reduction of GAD activity which could not be reversed by the addition of pyridoxal‐5′‐phosphate (PLP). Since inhibition of GAD activity by AOAA could be readily reversed by PLP, the reduction of GAD activity measured in the presence of added PLP indicated a decrease in the level of GAD apoenzyme. Similarly, increase of GABA content by hydrazine was also accompanied by a reduction in the level of GAD. Thiosemicarbazide and hydroxylamine did not affect the content of GABA appreciably, and in both cases levels of GAD remained unchanged when measured in the presence of added PLP. The correlation of the reduction in the levels of GAD with the increases in content of GABA suggests that GABA may regulate its own synthesizing enzyme by feedback repression.
AXONAL TRANSPORT OF PROTEINS IN THE HYPOTHALAMO‐NEUROHYPOPHYSIAL SYSTEM OF THE RAT
Authors: Norströ A. , Sjöstrand J.
Published: October 2006

—Axonal transport of proteins in the hypothalamo‐neurohypophysial system of the rat was studied after a local injection of [35S]cysteine in the region of the supraoptic nucleus. The migration of labelled proteins was followed by measuring the specific radioactivity of the proteins in various parts of the hypothalamo‐neurohypophysial tract. Between 2 and 4 h after the isotope injection there was a sharp increase in the protein‐bound specific radioactivity of the posterior pituitary lobe, demonstrating that a transport of 35S‐labelled proteins had occurred from the supraoptic nucleus to the neurohypophysis. The rate of the transport was 2‐3 mm/h. During the first 24 h after the injection a continuous accumulation of labelled material occurred in the neural lobe. Considerable radioactivity could still be recovered 6 days after the isotope injection.

Fractionation of the neurohypophysial proteins by polyacrylamide gel electrophoresis revealed that approximately 90 per cent of the radioactivity of the soluble proteins was recovered in a single protein fraction. Labelling of this fraction was not observed until 2 h after isotope injection. The radioactivity increased markedly up to 4 h. It is suggested that this protein component is involved in the neurohypophysial response to osmotic stress since the protein disappeared from the posterior lobe upon dehydration of the rat.
ELECTROPHORETIC CHARACTERIZATION OF BASIC PROTEINS IN ACID EXTRACTS OF CENTRAL NERVOUS SYSTEM TISSUE
Authors: Martenson R. E. , Deibler Gladys E. , Kies Marian W.
Published: October 2006

Abstract—

A technique has been outlined for identification of myelin basic proteins in mixtures of CNS proteins. Myelin basic proteins can be recognized easily by high cathodic mobility at low pH, a unique electrophoretic pattern exhibited at high pH and a characteristic colour when complexed with Amido black. The major protein extracted at pH 3·0 from either brain or spinal cord is myelin basic protein. In the low pH electrophoretic pattern of these extracts it is the most conspicuous component and the component migrating farthest cathodically; it does not appear in comparable electrophoretic patterns of liver extracts. Guinea pig myelin basic protein appears as a single dense blue‐green band in low pH electrophoretic patterns, in contrast to the other proteins which are stained greyish‐blue or greyish‐purple by Amido black. The pattern of rat myelin basic protein is similar except that it consists of a pair of dense blue‐green bands.

A third characteristic which facilitates the identification of myelin basic proteins in mixtures is a considerable cathodic mobility and electrophoretic heterogeneity at pH 10·6. Most other basic CNS proteins barely penetrate the gel at this pH. We have also examined in detail the behaviour of two other components of pH 3·0 extracts which migrate close to myelin basic protein at low pH. Both are present in pH 3·0 extracts of liver and brain but not of spinal cord, and both stain grey instead of blue‐green, a characteristic which readily distinguishes them from myelin basic protein. Neither of these components affects the characteristic pattern of microheterogeneity observed in high pH electrophoretograms of myelin basic proteins. One of these components has been purified and tentatively identified as lysine‐rich histone F1.
ISOLATION OF TWO PANTOTHEINE‐CONTAINING ACIDIC PROTEINS FROM MONKEY BRAIN
Authors: Reichelt K. L.
Published: October 2006

The isolation of two acid‐soluble proteins from Macaca irus brain is reported. The proteins contained 34 and 35.6 per cent polar amino acids, respectively. One protein had a mol. wt. of approx. 37,100 and the other of 23,000 with subunits of 11,500. Each protein contained 4′‐phosphopantetheine, which was hydrolytically determined as taurine and β‐alanine and microbiologically as pantothenate. The smaller protein is found to be present in the supernatant following homogenization both in 0‐32 M‐sucrose and in 0‐32 M‐sucrose with 40 mm‐NaCl. The larger protein is also mainly present in the supernatant fluid. The function of these proteins is unknown, but the mol. wt. 23,000 species could be acetylated from glucose and acetate in mouse brain tissue slices and the acetyl groups could be isolated as the hydroxamate.
METABOLISM OF PUTATIVE TRANSMITTERS IN INDIVIDUAL NEURONS OF APLYSIA CALIFORNICA
Authors: MCaman R. E. , Dewhurst Susan A.
Published: October 2006

The activities of acetylcholinesterase (acetylcholine acetyl‐hydrolase; EC 3.1.1.7) and catechol‐O‐methyl transferase (S‐adenosylmethionine: catechol‐O‐methyl transferase; EC 2.1.1 .a) were measured in the various ganglia of the nervous system of Aplysia californica and in some of the individually identifiable neurons in these ganglia. All of the neurons studied had measurable levels of activity for both enzymes. Since different individual neurons exhibited approximately the same level of activity we concluded that neither of these enzymes could be used to classify neurons as ‘cholinergic’ vs. ‘aminergic’ or ‘cholinoceptive’ vs. ‘aminoceptive'. The ubiquitous distribution of either or both of these enzymes in different single neurons may be related to glial contamination.
REGULATION OF PROTEIN SYNTHESIS IN DEVELOPING MOUSE BRAIN TISSUE: IN VITRO BINDING OF TEMPLATE RNA TO BRAIN RIBOSOMES
Authors: Lerner M. P , Johnson T. C
Published: October 2006

Abstract— Ribosomes, isolated from brain tissue of mice of various ages, were tested for their ability to participate in cell‐free protein synthesis and to bind polyuridylic acid. Although protein synthesis was markedly reduced by ribosomal preparations obtained from increasingly older animals, no significant differences could be measured with respect to template RNA binding. Similar binding properties were also measured with ribosomal subunits purified from young and mature brain cell ribonucleoprotein particles. In addition, no differences could be detected in the relative firmness of template RNA binding that could explain the maturation‐dependent loss in ribosomal activity.
FAST AXONAL TRANSPORT IN VITRO IN THE SCIATIC SYSTEM OF THE FROG
Authors: Edström A. , Mattsson H.
Published: October 2006

Abstract— An in vitro system from the frog has been used to study fast axonal protein transport. The preparation, which was incubated in a specially made chamber, consisted of the gastrocnemius muscle, the sciatic nerve, the dorsal ganglia and part of the spinal cord. The parts were separated from each other by silicone grease barriers, which made it possible to follow the migration of labelled proteins from the spinal cord and ganglia, along the sciatic nerve, towards the muscle. About 80 per cent of transported proteins in the sciatic nerve originated from the dorsal spinal ganglia and moved antidromically at a rate of 60–90 mm per day at 18°C. The rapidly transported proteins were 90 per cent particulate and mainly associated with structures sedimenting in the microsomal fraction.

The effects of cyclohexirnide showed that the synthesis of rapidly moving proteins and their transport were separate processes. A low concentration of colchicine inhibited the transport when it was present in the medium surrounding the ganglia, but had no effect even at a higher concentration, when it was added to the nerve compartment. The presence of vinblastine at a low concentration in either of the two compartments completely arrested the protein transport. Likewise N‐ethylmaleimide or p‐chloromercuribenzene sulphonic acid in the nerve medium effectively blocked the fast transport. Results from experiments performed to test the possibility of disto‐proximal flow and of transfer of proteins from the muscle to the nerve are discussed.
DISTINCT PATTERNS OF ENTRY OF TWO NONMETABOLIZABLE AMINO ACIDS INTO BRAIN AND OTHER ORGANS OF INFANT GUINEA PIGS1,2
Authors: Schain R. J. , Watanabe Kathy S.
Published: October 2006

Abstract— Entry of [3‐14C] α‐aminoisobutyric acid (AIB) and [1‐14C] 1‐aminocyclopentanecarboxylic acid (cycloleucine) into the brain and other organs of the infant guinea pig has been investigated in vivo. The entry of [14C]AIB into brain was markedly restricted in comparison to its entry into other organs. The mean distribution ratio (14C in tissue water/14C in plasma water) achieved in brain at 45 min after administration of a pulse of [14C]AIB was 0.3. All other organs studied concentrated [14C]AIB from the blood stream, with the greatest uptake occurring in liver and kidney, in which distribution ratios reached values of 5–10. In contrast to AIB, [14C]cycloleucine entered the brain at a rate approximately the same as that into other organs. Distribution ratios for [14C]cycloleucine ranged between 0.5 and 2.0 for all organs. During the first few days of postnatal life, there was a sharp increase of concentrative uptake of [14C]AIB into liver and kidney. The entry of [14C]AIB into brain remained unchanged during this period. There was a small (35 percent) decrease in the rate of entry of [14C]cycloleucine into brain during the first 3 days of postnatal life. Since [14C]AIB is known to be concentrated from the surrounding medium by brain slices in vitro, we concluded that the locus of restriction of the entry of [14C]AIB into the brain in vivo is at the blood‐brain barrier. We hypothesize that this property of the barrier is important in preventing concentrative uptake of pharmacologically active and potentially harmful amino acids by brain tissue.
METABOLISM OF INTRACEREBULLY ADMINISTERED HISTIDINE, HISTAMINE AND IMIDAZOLEACETIC ACID IN MICE AND FROGS1
Authors: VAN Balgooy J. N. A. , Marshall F. D. , Roberts E.
Published: October 2006

Abstract— After intracerebral administration of [14C]histidine to mice the major labelled substance found in the brain extracts was histidine itself; small amounts of labelled carnosine and homocarnosine were detected. No other labelled substances were detected on radio‐ autographs of two‐dimensional TLC's of the extracts. In the case of the frog, radioactive histidine, N‐acetylhistidine, carnosine and homocarnosine were found in the brain extracts at various times after intracerebral injection of the labelled histidine. With time, approximately 90 per cent of the radioactivity in the extracts was found in the N‐acetylhistidine. In neither the mouse nor frog could we find unequivocal evidence for the formation either of histamine or imidazoleacetic acid from intracerebrally administered histidine, but our analytical procedures may have lacked sufficient sensitivity to pick up extremely low activities of histamine and imidazoleacetic acid. Experiments with [14C]histamine administered intracerebrally into mice demonstrated the major pathway of metabolism in brain to be histamine → methylhistamine → methylimidazoleacetic acid. No detectable label appeared in inlidazoleacetic acid. In the frog intracerebral administration of the labelled histamine led to the formation of methylhistamine and imidazoleacetic acid, but at most only traces of methylimidazoleacetic acid were found. The injection of [14C]imidazoleacetic acid intra‐ cerebrally into mice and frogs resulted in virtually no loss of the label in the form administered in the frog brain over a period of 4 h and in a slow rate of decrease in the mouse brain. No radioactive metabolites of imidazoleacetic acid were found in either species. The limitations of trying to determine natural functions of substances in brain by following the fate of exogenously administered materials is discussed.
CALCIUM MOVEMENTS IN BRAIN SLICES IN LOW SODIUM OR CALCIUM MEDIA
Authors: Stahl W. L. , Swanson P. D.
Published: October 2006

Abstract— Movement of 45Ca into and out of cerebral slices in vitro was altered by incubation in Na‐free medium or in the presence of ouabain. 45Ca uptake into the ‘non‐inulin’ space was more than doubled in slices that were losing Na into Na‐deficient media. Replacement of Na in the incubation medium by choline chloride reduced the efflux of 45Ca into Ca‐free medium. In the presence of ouabain (10‐4M), the rate of efflux was also reduced. NaCN or NaCN plus ethacrynic acid increased the rate of 45Ca efflux. The data are compatible with a sodium‐calcium exchange mechanism in cerebral slices.
METABOLISM OF POLYAMINES IN NORMAL AND SCRAPIE‐AFFECTED MOUSE BRAIN AND SPLEEN
Authors: Giorgi P. P. , Field E. J. , Joyce Greta
Published: October 2006

Abstract— Following intracerebral inoculation of mouse adapted scrapie agent into mice, polyamine concentration in the brain decreases to about 75 per cent of the normal level during the first 2 months after intracerebral inoculation of the agent. Between 2 and 4 months after infection thelevel of spermidine and spermineincreased by 80 and 40 percent respectively to reach concentrations of 25 and 20 per cent higher than controls of the same age. During the same period the rate of incorporation of [14C]putrescine into spermidine is increased four‐fold as compared with controls. The changes in polyamine levels correlate well with the pattern of astrocyte hypertrophy and are similar to those reported for human brain tumours. The concentration of polyamines in spleen increases soon after inoculation. Whilst changes in brain polyamines might be referred to the hypertrophic growth of astrocytes those in spleen are perhaps due to an increased metabolic activity of spleen cells associated with the replication of the agent. These results are derived from experimental mouse scrapie and not naturally occurring disease in sheep.
PURIFICATION AND PROPERTIES OF BRAIN ACETYL‐CHOLINESTERASE (EC 3.1.1.7)1
Authors: Chan S. L. , Shirachi D. Y. , Trevor A. J.
Published: October 2006

Abstract— Approximately 50 per cent of the total AChE of brain tissue was solubilized by a simple procedure of repeated homogenization and centrifugation in 0.32 M‐sucrose containing EDTA. Ion‐exchange and molecular‐sieve chromatography demonstrated two peaks of AChE activity which apparently differed with respect to charge properties and molecular size. The most active preparation of AChE, which hydrolysed 13,500 μMmoles of acetylthiocholine/mg of protein/h, had an estimated molecular weight of 291,000 and was contaminated by a single protein component, as judged by disc gel electrophoresis.
RESPIRATORY ACTIVITY OF GUINEA PIG BRAIN NUCLEI
Authors: Mukherjee S. K. , Narayanaswami A.
Published: October 2006

Abstract— Preparations of guinea pig brain nuclei, obtained by discontinuous gradient centrifugation in sucrose solutions of pH 6.7–6.8, containing 3 mM‐MgCl2 and phosphate exhibited steady and reproducible oxygen uptake. Oxygen uptake was stimulated 60–70 per cent by glucose, pyruvate, oxalacetate or α‐ketoglutarate and 267 per cent by succinate. This respiratory activity was unaffected by the relative sodium or potassium ion content of the medium and by variations in the concentration of inorganic phosphate. Agents known to inhibit citric acid cycle oxidation, oxidative phosphorylation and glycolysis diminished oxygen uptake, but antibiotics inhibiting nucleic acid or protein synthesis did not. Treatment of the nuclear preparation with DNase decreased respiratory capacity, which was partially restored by the addition of polyacrylic acid.