bluuebunny/crossref_metadata_2025_split huggingface dataset:
TRANSPORT OF CHOLINE ACETYLTRANSFERASE AND ACETYLCHOLINESTERASE IN THE RAT SCIATIC NERVE: A BIOCHEMICAL AND ELECTRON HISTOCHEMICAL STUDY
Authors: Kéasa P. , Mann S. P. , Karcsu Sarolta , Tóth L. , Jordan Susan 
Published: October 2006

AbstractThe transport of acetylcholinesterase (AChE) and choline acetyltransferase (ChAc) were investigated by biochemical and histochemical methods. After ligature of one of the sciatic nerves of the rat for varying times—4, 14, 20 and 44 h—the normal levels and the accumulation of AChE and ChAc activities were investigated. It can be inferred from the results that there is a rapid accumulation of AChE activity just proximal to the ligature, while the increase in ChAc activity is less pronounced. Distal to the ligature the level of AChE is above the control value whereas, in contrast to this, the ChAc activity is significantly decreased. Histochemical demonstration of the two enzymes indicates that they are present in the cholinergic axons. The reaction end‐product produced by AChE occurs within vesicles and neurotubules, while the endproduct due to ChAc appears to be free in the axoplasm, bound to neurofilaments and on the outer surface of vesicles and tubules.
ANALYSIS OF THE MAJOR AMINO ACIDS OF RAT BRAIN AFTER IN VIVO INHIBITION OF GABA TRANSAMINASE BY ETHANOLAMINE O‐SULPHATE
Authors: Fowler L. J. 
Published: October 2006

AbstractThe effect of in vivo inhibition of GABA transaminase by ethanolamine O‐sulphate on the content of the free amino acids in rat brain has been studied. Intracisternal injection of 2.0 mg/kg resulted in a progressive increase in GABA levels with time, to reach after 8 h a 100 per cent increase over saline‐injected control animals. The effect of injection of 0.5, 1.0 and 2.0 mg/kg was studied 24 h after injection and the results showed that the increased GABA levels were dependent on the dose of inhibitor employed. Apart from the substantial increase in the GABA concentration of the brain there were no significant changes in the content of the other amino acids except for a small but significant decrease in aspartic acid in one experiment. When the extent of inhibition of the transaminase was correlated with the rise in GABA concentration it was shown that no elevation occurred until more than half of the enzymic activity had been inhibited.
LIPID AND PROTEIN CHANGES IN SCIATIC NERVE DURING WALLERIAN DEGENERATION
Authors: Wood J. G. , Dawson R. M. C. 
Published: October 2006

AbstractLipid and protein changes have been measured and correlated during early Wallerian degeneration in the same rat sciatic nerve. The major structural glycoprotein disappears at a steady rate and little remains after 8 days. There is a concomitant appearance of a protein with the same molecular size as basic protein B2 and which is probably formed from the glycoprotein. Basic protein (B1) is slowly lost, but Wolfgram protein tends to increase possibly because of glial cell proliferation. Cholesterol ester has appeared 3 days after sectioning, while cholesterol and probably cerebroside are reduced. Triglyceride levels show considerable variation, but biphasic increases tended to occur at 3‐4 and 10‐14 days. Loss of phospholipids is a later event. The changes in lipid and protein are discussed in relation to the stability of the peripheral nerve myelin membrane.
INTRASYNAPTOSOMAL CONVERSION OF TYROSINE TO DOPAMINE AS AN INDEX OF BRAIN CATECHOLAMINE BIOSYNTHETIC CAPACITY1
Authors: Kuczenski R. , Segal D. S. 
Published: October 2006

Abstract—The potential for intrasynaptosomal conversion of tyrosine to dopamine was evaluated in the cell bodies (substantia nigra) and nerve terminals (caudate‐putamen) of the nigral‐striatal dopaminergic pathway. The conversion technique involves measurement of 14CO2 evolved from carboxyl‐labelled tyrosine in the absence of both exogenous pteridine cofactor and DOPA decarboxylase. Evaluation of apparent Km values for tyrosine uptake and conversion and observed maximal velocities suggest that conversion is not limited by movement of substrate into the synaptosomes. The results, based on brain regional and subcellular distribution, are consistent with the localization of conversion in nerve endings and suggest a rapid and reliable measure for catecholamine biosynthetic capacity when structural integrity of the nerve ending is maintained.
BIOCHEMICAL STUDIES ON DEGENERATIVE NEUROLOGICAL DISORDERS: 1. ACUTE EXPERIMENTAL ENCEPHALITIS
Authors: Bowen D. M. , Flack R. H. A. , Martin R. O. , Smith Carolyn B. , White Pamela , Davison A. N. 
Published: October 2006

Abstract—Weanling mice were either injected with viruses or fed cuprizone. Changes in total activity of two cathepsins and two β‐glycosidases were characteristic of each of the five acute encephalopathies studied. Comparisons made between morphological change and hydrolase activity shows that β‐galactosidase and cathepsin A may be useful indices of neuronal degeneration and cellular infiltration into white matter, respectively. β‐Glucuronidase appears to be a particularly sensitive index of cellular reactions to injury. Cathepsin D activity does not appear to reflect any one type of neural cell. Although the morphological changes included neuronal degeneration, perivascular cuffing with mononuclear cells, astrocytic hypertrophy and microgliosis none of the experimental conditions mimicked biochemical changes in multiple sclerosis or senile dementia. The measurement of lysosomal enzymes appears to be a more sensitive indication of acute neurological disorder than the screening of brain proteins by polyacrylamide gel clectrophoresisor the measurement of enzymes (acetylcholinesterase, DOPA decarboxylase and carbonic anhydrase) characteristic of neural cells.
DIFFERENT RECOVERY RATES OF THE ELECTROPHYSIOLOGICAL, BIOCHEMICAL AND MORPHOLOGICAL PARAMETERS IN THE CHOLINERGIC SYNAPSES OF THE TORPEDO ELECTRIC ORGAN AFTER STIMULATION
Authors: Zimmermann H. , Whittaker V. P. 
Published: October 2006

Abstract—During stimulation there occurred a decay in electrical response, vesicular acetylcholine, ATP and nucleotide as well as a loss of vesicle number and a decrease in vesicle diameter in the electric organ of Torpedo. These alterations were re‐established during a subsequent recovery period. The different parameters recovered at different rates. Firstly, electrical response to single pulses recovered to prestimulation values within about 5 h. Vesicle number and diameter as well as bouton size were found to be re‐established fully after 24 h. The newly formed vesicles appeared to be empty as vesicular acetylcholine, ATP and total nucleotide recovered much more slowly and were back to control values after about three days. Acetylcholine reappeared more quickly in the vesicles than ATP. Only after recovery of the vesicular pool of transmitter and ATP did the electric organ regain full stability of the electric discharge pattern on restimulation.
EFFECT OF ACTINOMYCIN‐D ON LABELLED MATERIAL IN THE RETINA AND OPTIC TECTUM OF GOLDFISH AFTER INTRAOCULAR INJECTION OF TRITIATED RNA PRECURSORS
Authors: Ingoglia N. A. , Grafstein Bernice , McEwen B. S. 
Published: October 2006

Abstract—After injection of [3H]guanosine or [3H]uridine into the eye of goldfish, labelled acid‐soluble radioactivity and RNA appeared in the contralateral optic tectum. When 0·1 μg actinomycin‐D was injected into the eye 4 h before the precursor, the labelled RNA in the retina by 18 h after the injection was only 23 per cent of normal, but the acid‐soluble radioactivity in the retina and the small amount of labelled acid‐soluble material conveyed to the tectum were not significantly affected; by 15–20 days after the injection the acid‐soluble radioactivity in the retina was reduced and the amount of labelled material conveyed to the tectum, including both RNA and acid‐soluble fractions, was less than normal.When the actinomycin was injected at various times before or after the precursor and measurements were made 6 days later, it was found that the amount of labelled RNA conveyed to the tectum was maximally decreased if the inhibitor was given simultaneously with or up to 4 h before the precursor, whereas the amount of RNA was normal if the incorporation of the precursor had been allowed to proceed for 12 h before the inhibitor was given. This result would be consistent with the view that much of the RNA conveyed to the tectum had been synthesized in the retina within 12 h of the injection of the precursor, and had then presumably been axonally transported in the optic nerve to the tectum. However, since the acid‐soluble material conveyed to the tectum was also reduced as a result of the actinomycin treatment, the results of these experiments with actinomycin do not unequivocally rule out the possibility that the RNA appearing in the tectum had been locally synthesized from the axonally transported acid‐soluble material. In the retina, both the labelled RNA and acid‐soluble fractions were reduced, to about 15 and 60 per cent of normal, respectively, without any relationship to the time between the injection of inhibitor and precursor. The discrepancy between the effects of the labelling of the retina and the labelling of material conveyed to the tectum could be correlated with the fact that the actinomycin caused severe damage to the retinal receptor cells, while leaving the ganglion cells relatively intact. The more pronounced effect of actinomycin on the receptor cells could in turn be correlated with the fact that these cells had a higher rate of RNA synthesis than the ganglion cells. This was demonstrated autoradiographically by the higher rate of incorporation of [3H]uridine into the receptor cells.Intracranial injection of actinomycin did not affect significantly the amount of labelled RNA conveyed to the tectum, which would argue against the local synthesis of this RNA. It is not certain, however, that the actinomycin penetrated deeply enough into the tectum to be effective.
SEROTONIN AND FREE AMINO ACID ANALYSIS OF GANGLIA AND ISOLATED NEURONES OF APLYSIA DACTYLOMELA
Authors: Cottrell G. A. 
Published: October 2006

Abstract—The presence of serotonin and different amino acids was investigated in the ganglia and in isolated giant neurones of Aplysia dactylomela. With a few exceptions the pattern of substances was similar in all the ganglia. Of the many identified neurones studied only one giant neurone located in each cerebral ganglion was found to contain serotonin. GABA was detected in most extracts, including those of the serotonin‐containing neurone, known cholinergic, and known neurosecretory neurones. Putrescine, recently detected in extracts of nervous tissue and isolated neurones of Helix, was not detected in Aplysia nervous tissue.
UPTAKE AND METABOLISM OF GLUTAMATE BY ISOLATED TOAD BRAINS CONTAINING DIFFERENT LEVELS OF ENDOGENOUS AMINO ACIDS
Authors: Shank R. P. , Baxter C. F. 
Published: October 2006

Abstract—The uptake of [U‐14C]glutamate into the amphibian brain was studied in vitro using brains from toads (Bufo boreas) adapted either to a fresh water (FWA) or an hyperosmotic saline (HOA) environment. Initial rates of 14C‐glutamate uptake showed a single apparent Km of about 0·2 mm. Uptake by HOA brains was slower than that by FWA brains, reflecting perhaps a non‐competitive type of inhibition by the higher content of glutamate in the HOA brains. Although the glutamate content of HOA brains was maintained during prolonged incubation at twice the level found in FWA toads, other metabolic parameters measured in the two types of brain preparations were surprisingly similar. Tissue to medium concentration ratios of greater than 3000:1 were generated by both FWA and HOA brains. In both brain systems the clearance of glutamate from the medium was accompanied by a rapid conversion of the amino acid to glutamine and its release into the medium. In both the FWA and HOA toad brain systems some [U‐14C]glutamate was metabolized to aspartate and GABA; in both systems the specific radioactivity (SA) of glutamine in the tissue was from two to four times greater than that of glutamate; also the SA of glutamine released into the medium was higher by several orders of magnitude than the SA of glutamine in brain tissues.These and other findings support the concept that, in both the FWA and HOA toad brains, transport processes are instrumental in preserving low extracellular levels of glutamate but that mechanisms other than transport are responsible for the maintenance of different levels of glutamate in the FWA and HOA toad brains.
INHIBITION OF AMINO ACID UPTAKE BY THE ABSENCE OF Na+ IN SLICES OF BRAIN
Authors: Lajtha A. , Sershen H. 
Published: October 2006

Abstract—The Na+ requirement of amino acid transport was measured in brain slices. The tissue was first washed free of Na+ and then Na+ was replaced by one of the following: choline, Li+, Rb+, or mannose. Amino acid uptake was measured at different times (5–120 min) and at low (10‐7–10‐5m) and high (10‐3m) concentrations. Most of the Na+ could be washed out of the tissue; this also decreased K+ levels despite increased K+ in the medium. K+ tissue levels were partially restored when Na+ was added.The absence of Na+ abolished the uptake of Glu, Asp, GABA, Gly, Tau and Pro. Most of the neutral amino acids (Ala, Val, Trp, His) were very strongly inhibited by the absence of Na+ under most experimental conditions. Basic amino acids (Arg, Lys) were not completely inhibited, in that 30 per cent of the equilibrium uptake remained and some of the basic amino acid influx was independent of the Na+ tissue level. The uptake of amines (tyramine, cadaverine, putrescine) did not require Na+, and often was greater in the absence of Na+.We conclude that amino acid uptake in brain slices is Na+ dependent, although the absence of Na+ may affect transport indirectly.
FRACTIONATION OF RNA FROM BRAIN SYNAPTOSOMES AND CYTOPLASMIC SUBCELLULAR FRACTIONS
Authors: Cupello A. , Hydén H. 
Published: October 2006

Abstract—RNA from rat brain synaptosomes, mitochondria and microsomes was analysed by gel electrophoresis under conditions allowing good resolution in three different molecular weight ranges: 4s‐16s, 16s‐28s and >28s.Two synaptosome specific RNA bands were found, one with comparatively low molecular weight (8‐9 × 104 Daltons) and another very large (sE > 60s).RNA species with electrophoretic characteristics similar to those reported for liver mitochondrial RNA were found in brain mitochondria. From the electrophoretic data their mean geometric radii were determined.
AN IMPROVED METHOD FOR THE MEASUREMENT OF 14CO2 APPLIED TO A PROBLEM OF CYSTEINE METABOLISM IN SQUID NERVE
Authors: Hoskin F. C. G. , Pollock M. L. , Prusch R. D. 
Published: October 2006

Abstract—A method has been developed for the measurement of metabolically evolved 14CO2 which reduces contamination, utilizes conventional scintillation counting equipment, and makes possible direct comparisons with liquid samples without the need for large correction factors. The application of the method reveals that cysteine is transported into squid axons where much of it is decarboxylated, but where very little of the remainder of the molecule is metabolized to CO2. In contrast, pyruvate is taken up much more slowly, probably by diffusion, but is almost entirely metabolized to CO2. Thus cysteine does not appear to be appreciably metabolized by squid nerve via a ‘pyruvate pathway’. Although only a little appears to be metabolized via a ‘taurine pathway’, that small portion goes mainly to hypotaurine, and none goes beyond to isethionate.
THE INTRINSIC FLUORESCENCE CHARACTERISTICS OF THE MYELIN BASIC PROTEIN
Authors: Jones A. J. S. , Rumsby M. G. 
Published: October 2006

Abstract—The encephalitogenic basic protein has been isolated from the myelin sheath of ox brain white matter and the purity and amino acid composition have been verified. The intrinsic fluorescence characteristics of the purified basic protein have been determined and the results interpreted in terms of current ideas on the structure of the protein. Fluorescence data obtained from the basic protein in aqueous solution indicate that the tyrosine and tryptophan residues are largely exposed to the solvent and that resonance energy transfer from tyrosine to tryptophan is very inefficient. Denaturing conditions in 8 m‐urea have little effect on the fluorescence properties of the protein. The ionic detergent, sodium dodecyl sulphate, interacts with the basic protein and alters the fluorescence properties in a manner which indicates that the tryptophan residue is in the hydrocarbon chain region of the detergent while the local positive charge around the tyrosine residues is neutralized by the negatively charged sulphate head‐groups. The fluorescence results suggest that the basic protein can be used as a natural, non‐perturbing probe which will report on its environment after it has reacted with other membrane components.
EFFECTS OF AMINO‐OXYACETIC ACID, ETHANOLAMINE‐O‐SULPHATE AND GABA ON THE CONTENTS OF GABA AND VARIOUS AMINES IN BRAIN SLICES
Authors: Starr M. S. , Tanner T. 
Published: October 2006

Abstract—The effects of amino‐oxyacetic acid, ethanolamine‐O‐sulphate and γ‐aminobutyric acid (GABA) on the contents of GABA, noradrenaline, dopamine and serotonin (5‐HT) in slices of rat hypothalamus and midbrain were studied in vitro using a simultaneous fluorimetric assay procedure. Following control incubations the levels of 5‐HT were raised, while the levels of the other substances remained steady. Amino‐oxyacetic acid caused a reduction in the contents of noradrenaline and 5‐HT, but had no effect on either GABA or dopamine. Ethanolamine‐O‐sulphate both raised the GABA content and lowered the noradrenaline content of slices, while the levels of dopamine and 5‐HT were not altered. The presence of GABA in the incubation medium produced complex changes in these levels, depending both on the dose of GABA used and the brain area studied. In the hypothalamus, 0·07 mm‐GABA caused an elevation in 5‐HT, a drop in noradrenaline, and no change in either GABA or dopamine. With 5 mm‐GABA, the noradrenaline level was raised slightly above control values and the endogenous GABA level doubled, while 5‐HT and dopamine levels were not different from controls. Similar changes in 5‐HT and GABA contents were observed with midbrain slices, but noradrenaline and dopamine were not affected. The possible modes of action of amino‐oxyacetic acid and ethanolamine‐O‐sulphate on the amino acid and amine systems in the brain are discussed.
PARTIAL CHARACTERIZATION OF BASIC PROTEINS OF CHICKEN, TURTLE AND FROG CENTRAL NERVOUS SYSTEM MYELIN
Authors: Martenson R. E. , Deibler Gladys E. 
Published: October 2006

Abstract—Myelin basic proteins were isolated from CNS tissues of chicken, turtle and frog and compared with the corresponding protein of bovine origin. At acid pH all four proteins had comparable mobilities in polyacrylamide gels. Upon electrophoresis at alkaline pH the submammalian proteins, like the bovine protein, were separated into multiple components. The components of the chicken and frog proteins had exceptionally high and low mobilities, respectively, while those of the turtle protein had mobilities comparable to those of the bovine protein. The chicken and turtle proteins were similar to the bovine protein in amino acid composition except for containing considerably more serine and valine and having higher proportions of histidine to lysine. The frog protein differed further in having an unusually high content of tyrosine (approx 9 mol/mol protein), an unusually high arginine: glycine ratio (1.09) and practically no methylated arginine (0‐0.036 mol/mol protein). Like those of mammalian origin, the submammalian proteins each contained a single tryptophan and two methionines. Arginine, serine and glycine together accounted for approximately 40 per cent of the residues in each protein. The chicken and turfle proteins each contained roughly equal amounts of NG‐monomethyl‐ and NG, NG‐dimethylarginine, the two derivatives together comprising 0.5‐0.6 mol/mol protein. No NG, NG‐dimethylarginine was detected in any of the proteins examined. The microheterogeneity observed in the chicken and turtle proteins upon electrophoresis at alkaline pH was reproduced upon alkaline pH chromatography on carboxymethylcellulose. Chromatographic fractions of the chicken protein which differed electrophoretically at alkaline pH had virtualy identical amino acid compositions and apparent molecular weights and all contained comparable amounts of both NG‐monomethyl‐ and NG, NG‐dimethylarginine. Treatment of the submammalian proteins with BNPS‐skatole yielded two fragments comparable in size, charge and staining characteristics to those similarly produced from the bovine protein (residues 1‐116 and 117‐170). Fragments produced from the frog protein by treatment with BrCN were comparable in size and charge to those similarly produced from the bovine protein; those produced from the chicken and turtle proteins were much different. In immunodiffusion studies the submammalian and bovine proteins showed reactions of identity when tested against rabbit anti‐chicken basic protein serum.
AMINO ACID TRANSPORT IN PERIPHERAL NERVE: SPECIFICITY OF UPTAKE
Authors: Wheeler D. D. 
Published: October 2006

Abstract—Amino acid uptake has been studied in desheathed frog sciatic nerve. Results indicate that at least two types of processes are involved: a non‐saturable process, possibly simple diffusion, and a saturable, carrier‐mediated process. There appear to be several carrier‐mediated transport mechanisms, which can be separated on the basis of their substrate specificity as follows: small neutral, large neutral, β‐alanine, acidic, basic, aromatic and heterocyclic, and proline. The specificity of some of the mechanisms is incomplete and these can transport certain amino acids from other groups to a limited extent. The percentage of total uptake by a saturable process is highly variable. Basic, acidic, and those amino acids containing aromatic or heterocyclic ring structures are taken up primarily by a saturable process; small and large neutral amino acids and proline are taken up primarily by a non‐saturable process.
POSSIBLE DEFECT IN CHOLINERGIC NEURONS OF MUSCULAR DYSTROPHIC MICE1
Authors: Trabucchi M. , Cheney D. L. , Susheela A. K. , Costa E. 
Published: October 2006

Abstract—The cholinoacetyltransferase activity (CAT) in diaphragm of mice of Bar Harbor strain (129 ReJ dy/dy) with muscular dystrophy was significantly lower than that of phenotypically normal litter mates (129 ReJ dy/+). CAT, tyrosine hydroxylase (TH), dopamine‐β‐hydroxylase (DβH) activities were found identical in adrenal gland and brain homogenates of normal and dystrophic mice. Subacute injections of atropine (72 μmol/kg i. p., twice daily for 3 days) failed to increase the activity of adrenal CAT in dystrophic mice but increased this enzyme activity in adrenals of normal litter mates. The concentration in brain of dopamine, norepinephrine, serotonin, acetylcholine (ACh), γ‐aminobutyric acid (GABA) and some of their precursors were measured. Only the concentration of ACh was significantly lower in the brain of muscular dystrophic mice. The rate of accumulation of brain ACh concentration after the injection of oxotremorine (5μmol/kg i. p.) is slower in muscular dystrophic animals than in normal litter mates. Furthermore, the turnover rate of ACh in total brain was slower in muscular dystrophic mice than in phenotypically normal litter mates. The turnover rate of brain dopamine and norepinephrine in these 2 groups of animals was similar.