bluuebunny/crossref_metadata_2025 huggingface dataset:
THE METABOLISM OF γ‐AMINOBUTYRIC ACID (GABA) IN THE LOBSTER NERVOUS SYSTEM–GLUTAMIC DECARBOXYLASE*
Authors: Molinoff P. B. , Kravitz E. A.
Published: October 2006

Abstract— The glutamic acid decarboxylase has been purified from the lobster central nervous system. Potassium ion (0‐075 m) and β‐mercaptoethanol (0‐025 m) were essential for enzyme activity. Enzyme had about 60 per cent of its optimal activity in the absence of added pyridoxal phosphate. Carbonyl reagents (10−4m‐hydroxylamine or amino oxyacetic acid) would abolish this residual activity. The pH optimum of the enzyme was about 8‐0.

Standard Michaelis‐Menten kinetics were applied to the decarboxylation of glutamate and a Km of 0.02 m was calculated. GABA inhibited the reaction (Ki= 1.25 × 10−3m), but the inhibition showed anomalous behaviour when graphed by the method of Lineweaver and Burk (1934). The GABA inhibition resembled competitive inhibition, but curves rather than straight lines intersecting at a common point on the velocity axis were obtained. This effect remains unexplained.

Preliminary studies failed to reveal any subunit structure of the enzyme. The sedimentation coefficient (.S20.w) was 6‐55 in a sucrose density gradient in an ultracentrifuge. This was unchanged by the addition of any of the agents that influence enzyme activity.

The subcellular localization of the decarboxylase was explored in crude homogenates of lobster central nervous system prepared in various ways. The major proportion (about 90 per cent) of the enzyme activity was in the soluble fraction.‘Particulate’enzyme could be prepared, but gentle suspension of this material in buffer liberated most of the activity.

A contaminant in the radioactive substrates led to the production of radioactive GABA without the simultaneous evolution of CO2. In this case, GABA production required active enzyme but was not an exclusive property of the glutamic decarboxylase activity.
MAPLE SYRUP URINE DISEASE METABOLITES STUDIED IN CEREBELLUM CULTURES1
Authors: Silberberg D. H.
Published: October 2006

Abstract— Myelinating cultures of rat cerebellum were exposed to the branched‐chain amino acids and their α‐keto derivatives at concentrations found in maple syrup urine disease. Decreased‐to‐absent and delayed myelination was produced by α‐keto‐isocaproic acid at physiological levels. Injury to small cells, probably glia, was also noted. The other metabolites failed to produce any visible damage.
CONTROL OF ACETYLCHOLINE SYNTHESIS—THE INHIBITION OF CHOLINE ACETYLTRANSFERASE BY ACETYLCHOLINE
Authors: Kaita A. A. , Goldberg A. M.
Published: October 2006

Abstract— The inhibition of choline acetyltransferase by acetylcholine in vitro occurs at a concentration of 10 mm and increases progressively to 45 per cent at a concentration of 100 mm. The inhibition is competitive for choline and noncompetitive for acetyl‐CoA. It is suggested that the synthesis of acetylcholine may be controlled by its accumulation in synaptic vesicles.
ASSOCIATION OF TYROSINE HYDROXYLASE WITH SYNAPTIC VESICLES IN BOVINE CAUDATE NUCLEUS1
Authors: Fahn S. , Rodman J. S. , Côté L. J.
Published: October 2006

Abstract— The subcellular distribution of tyrosine hydroxylase in the bovine caudate nucleus was investigated, with five other enzymes serving as biochemical markers, and coordinated with electron microscopic observations. Tyrosine hydroxylase is particulate bound and has relatively high specific activities in the synaptosome‐enriched subfractions and in the synaptic vesicle fraction. The association of tyrosine hydroxylase with the synaptic vesicles is consistent with the theory of feedback regulation of catecholamine synthesis.
THE METABOLISM OF TRITIATED DOPAMINE IN REGIONS OF THE RAT BRAIN IN VIVO—II
Authors: Taylor K. M. , Laverty R.
Published: October 2006

Abstract— The levels of tritiated catecholamines and metabolites were measured in regions of the rat brain at intervals after the intraventricular injection of [3H]dopamine, [3H]nor‐adrenaline and [3H]normetanephrine. The disappearance of catecholamines and appearance of metabolites with time and the regional turnover rates of these amines indicate that the major pathway of the metabolism of noradrenaline and dopamine actively released from physiological storage sites is to the neutral alcoholic metabolites. The acid metabolites, homovanillic acid and 3,4‐dihydroxyphenylacetic acid appear to be only minor products of normal dopamine metabolism in rat brain regions including the striate, but are the main end products of the metabolism of excess exogenous dopamine.

The active metabolism of stored noradrenaline to alcohol metabolites is also indicated by the increase in neutral alcohol metabolites accompanying the increased noradrenaline turnover when rats were subjected to electroshock stress. Therefore in the rat brain, neutral alcohol metabolites of dopamine and noradrenaline have great significance in the study of physiological catecholamine turnover in any region.
THE EFFECT OF PHOSPHOLIPASES ON THE UPTAKE OF ATROPINE AND ACETYLCHOLINE BY SLICES OF MOUSE BRAIN CORTEX
Authors: Heilbronn E.
Published: October 2006

Abstract—

The uptake of [3H]atropine, [3H]acetylcholine and [14C]inulin in mouse brain cortex slices was studied in slices treated with phospholipases A or C. In control experiments the slices took up atropine and acetylcholine against a concentration gradient, indicating active uptake. This uptake was decreased by ouabain, by anaerobic conditions and by an increase in the potassium ion concentration.

The phospholipases were found to decrease the uptake of atropine and particularly that of acetylcholine in the slices. The uptake of labelled inulin in enzyme‐treated slices, as compared to untreated slices, was not decreased, indicating no change in the inulin space. The effect of the phospholipases was time dependent and, up to a certainlimit, concentration dependent. The effect of ouabain in decreasing the uptake of atropine was not eliminated by the enzyme treatment. The effect of anaerobic conditions in decreasing the uptake was weak after treatment with phospholipases. The effect of higher concentrations of potassium ions was abolished by treatment with phospholipase A.

The results emphasize the importance of phospholipids as substances controlling structural order in membranes and suggest their participation in active transport.
DEPRIVATION OF PARADOXICAL SLEEP AND BRAIN GLYCOGEN
Authors: Karadzic V. , Mrsulja B.
Published: October 2006

Abstract— Rats deprived of paradoxical sleep (PS) for 72 hr showed a considerable fall of total glycogen in the subcortex and caudal brain stem. No important changes were discovered in the parts of the cerebral cortex which were examined. The stress of the experimental technique of PS deprivation did not lead to significant changes in glycogen content in any of the structures examined. It was concluded that changes in glycogen content corresponded specifically to PS deprivation stress.
ELECTROLYTE DISTRIBUTION IN RABBIT SUPERIOR CERVICAL GANGLION1
Authors: Woodward J. K. , Bianchi C. P. , Erulkar S. D.
Published: October 2006

Abstract— Superior cervical ganglia of the rabbit were removed and analysed for Na+, K+, Ca2+, Mg2+ and Cl−. The mean electrolyte content in μmole/g wet wt. was as follows: Na+, 64.7 ± 1.3; K+, 65.1 ± 2.7; Ca2+, 3.71 ± 0.28; Mg2+, 3.70 ± 0.50; and Cl−, 50.15 ± 2.26. Water content was 0.76 ± 0.01 ml/g wet wt. Extracellular space was 0.37 ± 0.01 ml/g, and the vascular space 0.0238 ± 0.0002. The mean resting potential of the rabbit superior cervical ganglion was – 68.6 mv. After correction for extracellular electrolyte content, the potential differences, ENa, EK and Ecl, were estimated to be +33.6 mv, –96.9 mv and ‐41.1 mv, respectively, in the ganglia.

Permeability coefficients for K+, Na+, and Cl− were estimated to be 1:0.06:0.02. Replacement of sodium in physiological saline solution by lithium results in a displacement of 94 per cent of the sodium content of the ganglion and 69 per cent of the potassium after 30 min of equilibration.
A QUANTITATIVE CYTOCHEMICAL STUDY OF THE DNA CONTENT OF NEURONS OF RAT CEREBELLAR CORTEX1
Authors: Lentz R. D. , Lapham L. W.
Published: October 2006

Abstract— Measurements of nuclear DNA content with quantitative cytochemical methods for determining amounts in single nuclei reveal tetraploid quantities of DNA in cerebellar Purkinje neurons of the rat, or twice the amount of nuclear DNA of rat somatic cells in general. The findings suggest that tetraploidy is probably a universal phenomenon among rat Purkinje cells. Granule and basket cells have a diploid DNA content.
THE CORRELATION BETWEEN CHOLINE ACETYLTRANSFERASE AND ACETYLCHOLINESTERASE ACTIVITY IN DIFFERENT AREAS OF THE CEREBELLUM OF RAT AND GUINEA PIG
Authors: Kása P. , Silver Ann
Published: October 2006

Abstract— Choline acetyltransferase (ChAc) and acetylcholinesterase (AChE) levels were measured quantitatively in samples from the archi‐ and paleocerebellar vermis (Larsell's Lobules IX c,d,‐X, and Lobules VII‐VIII, respectively) and from the cerebellar peduncles, nuclei and white matter of rat and guinea pig. Lesions to isolate archi‐ or paleocerebellar areas were made in some rats and the effect on enzyme levels and ultrastructure were studied. In the rat there was a striking correlation between the activity of ChAc and AChE in the different areas; thus in the archicerebellar cortex the levels of both enzymes were 3–4 times those in the paleocortex. Deafferentation caused a fall in ChAc and this practically paralleled the fall in AChE in the same area. The reduction in both enzymes was more pronounced in the archi‐ than in the paleocerebellar cortex. In the guinea pig the results were very different. The ChAc activity was much lower than in the rat and was equal in the archi‐ and paleocerebellum. The AChE activity was also uniform in the different areas but, in contrast to ChAc, was higher than in the rat.
THE DISTRIBUTION OF NUCLEIC ACIDS IN THE GIANT AXON OF THE SQUID (LOLIGO PEALII)1
Authors: Lasek R. J
Published: October 2006

Abstract— RNA and DNA were determined in the axoplasm and sheath of squid giant axons. If the RNA was related to axonal length, equivalent amounts of RNA were found in the axoplasm and sheath. However, when it was expressed as a function of dry wt. or residue protein, the concentration of RNA in the sheath was four times greater than in the axoplasm. A ratio of 1·1 was found for sheath RNA/sheath DNA. Less DNA was present in the axoplasm than the amount which could be accurately determined with the methods employed.
STOICHIOMETRIC RELATION OF PROTEIN COMPONENTS IN CEREBRAL MYELIN FROM DIFFERENT SPECIES1
Authors: Mehl E , Halaris A
Published: October 2006

Abstract— In cerebral myelin from man, ox, rabbit, guinea pig and chicken, the amounts of proteolipid protein, basic protein and the fraction of further protein components were found to be present in a fixed ratio of 5·0: 3·5: 2·0 by weight. The molecular weights of 25,000 and 35,000 as obtained for the basic protein and proteolipid protein might indicate that cerebral myelin contains one molecule of basic protein per molecule of proteolipid protein. This fixed ratio of protein components was found to be changed in myelin from the PNS and in cerebral myelin from rat and carp, with their exceptional basic proteins. Using the polyacrylamide‐gel electrophoresis it was possible to demonstrate that a homogeneous structural protein (the Folch‐Lees proteolipid protein) constitutes about 50 percent of the total amount of myelin proteins in all species studied. An attempt was made to correlate myelin protein and lipid patterns from various species.
HEXOSE MONOPHOSPHATE PATHWAY IN SYNAPSES1
Authors: Appel S. H. , Parrot B. L.
Published: October 2006

Abstract— Synaptosomes isolated from rat cerebral cortex converted [l‐14C]glucose more rapidly than [6‐24C]glucose to ,14CO2. The ratio of C‐l: C‐6 in 14CO2 was 3‐9, thus suggesting that the hexose monophosphate shunt (HMP) pathway was functional in synapses in vitro. When changes in the ratio of C‐l: C‐6 in 14CO2 were used as an index of shunt activity, glucose oxidation by this route was stimulated by electron acceptors as well as by neurohormones, including norepinephrine, acetylcholine and serotonin. Brain mince also exhibited a C‐l: C‐6 ratio of 3‐2 when short (15 min) incubations were employed. Negative results previously reported are attributable to prolonged incubation during which depletion of NADP or randomization of the labelled carbons in radioactive glucose could have occurred. Our experiments excluded the incorporation of glucose into macromolecules as a specific role for the hexose monophosphate pathway. The generation of NADPH for numerous metabolic reactions including the maintenance of membrane SH groups and the oxidation and hydroxylation reactions may represent the functions of the hexose monophosphate in synaptosomes and account for its stimulation by neurohormones.
THE DISTRIBUTION OF SYNAPTOSOMAL OXIDATIVE ENZYMES AFTER EXPOSURE TO DEOXYCHOLATE1,2
Authors: Moore W. V. , Lindall A. W.
Published: October 2006

Abstract— The distributions of NADH2 dehydrogenase, NADH, cytochrome c reductase and cytochrome oxidase have been determined utilizing synaptosomal isolation techniques. Deoxycholate was used to determine compartmentation and/or ‘latency’ of these activities. NADPH, dehydrogenase proved to be a soluble and mitochondrial enzyme and the activity of this enzyme was not appreciably changed by deoxycholate treatment. NADHg cytochrome c reductase proved to be a mitochondrial enzyme with considerable activity in microsomal fractions. Deoxycholate treatment increased activity in the synaptosomal fraction 8.3‐fold. A bimodal activation pattern was observed with synaptosomal and mitochondrial NADH, cyrochrome c reductase upon exposure to increasing concentrations of deoxycholate, with enhancement of activity at 0.25 % (w/v) and 0.50 % (w/v) deoxycholate. The enzyme was stable at concentrations of deoxycholate less than 0.25% (w/v) but was irreversibly inactivated at concentrations higher than 0.25% (w/v). The mechanism of this activation pattern appeared to be a combination of enzyme release and inactivation. Similar results were not observed in liver mitochondria.

Cytochrome oxidase, a known mitochondrial marker, exhibited a 17‐fold increase in synaptosomal activity with deoxycholate treatment. The synaptosomal cytochrome oxidase activity after deoxycholate treatment approached the activity in the free mitochondrial fraction. The percentage of mitochondrial protein in synaptosomal fractions was estimated to be about 30 per cent from a comparison of the respective total (deoxycholate‐treated) activities. On the basis of these data we suggest that the synaptosomal fraction possesses a relatively sizable energy‐producing potential which may be of significance in vivo.
ALCOHOL DEHYDROGENASE ACTIVITY IN RAT BRAIN AND LIVER
Authors: Raskin N. H. , Sokoloff L.
Published: October 2006

Abstract— A significant level of alcohol dehydrogenase activity has been demonstrated in the soluble fraction of rat brain. The pH optimum, kinetic properties and response to inhibitors are similar to those of liver alcohol dehydrogenase. The nutritional state of the animal, such as that associated with feeding or fasting, appeared to have no effect on the levels of the alcohol dehydrogenase activities in either liver or brain. A cerebral mechanism for the metabolism of ethanol may be involved in local biochemical adjustments in tissues during exposure to alcohol and may play a significant role in the pathogenesis of the neural disorders which can accompany chronic alcohol ingestion or acute withdrawal.
TRANSAMINATION OF AMINO ACIDS IN HOMOGENATES OF RAT BRAIN
Authors: Benuck M. , Stern F. , Lajtha A.
Published: October 2006

Abstract— The aminotransferase activity of homogenates of brains from adult and neonatal rats has been investigated. Aminotransferase activity was demonstrated wtih 15 of 22 amino acids incubated with seven keto acids. The basic amino acids exhibited little or no activity.

The greatest activity was obtained when glutamate or aspartate was incubated with α‐ketoglutarate or oxaloacetate. Significant activity was also observed when the neutral aliphatic and aromatic amino acids were incubated with these two keto acids.

Activity with pyruvate was obtained principally upon incubation with glutamate and alanine. Most of the other amino acids that underwent transamination with α‐ketoglutarate also did so with pyruvate, although at a lower rate.

When phenylpyruvate was added to the medium, glutamate, phenylalanine and tyrosine transaminated most actively.

Incubations with 11 amino acids and glyoxylic acid demonstrated aminotransferase activity, with glutamate and ornithine being the most active substrates.

α‐Ketoisocaproate and α‐ketoisovalerate accepted amino groups primarily from the branched‐chain amino acids. Except for glutamate, activity with other amino acids was low or not detectable.

A comparison of aminotransferase activity in the newborn brain with that in the adult brain showed that the greatest change in activity occurred for glutamate with pyruvate or for alanine with α‐ketoglutarate, these activities increasing about 10‐fold from birth to adulthood; during this time activities with most other amino acids increased two‐ to threefold. Amino transfers from the branched‐chain amino acids showed no increase with maturation, and some reactions, such as that with methionine and a number of keto acids, decreased from birth to adulthood.

Our results correspond in general to previous studies of aminotransferase activity in brain and in liver. However, our study also indicates a possible second aminotransferase acting on the branched‐chain amino acids, the presence of aminotransferase activity for methionine and asparagine, and relatively high aminotransferase activity for glutamine or ornithine when incubated with glyoxylic acid rather than other keto acids. Moreover, phenylpyruvate and glyoxylate are active in amino transfers and may serve as substrates for a number of aminotransferases.
INCORPORATION OF [6‐3H] GLUCOSE INTO LIPID, PROTEIN, RNA AND DNA OF SLICES OF DIFFERENTIATING RAT CEREBRAL CORTEX1
Authors: Glazer R. I. , Weber G.
Published: October 2006

Abstract— An assay in vitro utilizing [6−3H)glucose as precursor for synthesis of lipids, proteins, RNA and DNA was developed for incubated slices of rat cerebral cortex. The developmental changes in synthesis of macromolecules were followed during differentiation of rat cerebral cortex. The incorporation of glucose into lipids and proteins decreased 10‐fold in incubated slices of cerebral cortex during progression from foetal to adult ages. In contrast, the specific radioactivities of RNA and DNA in incubated slices increased from the values at 3 days prepartum to peaks at 2–4 weeks postpartum.
PROTEIN DEGRADATION IN SQUID GIANT AXONS
Authors: Orrego F.
Published: October 2006

Abstract—

Axoplasm extruded from giant axons of the Chilean squid, Dosidicus gigas, contained a low level of neutral proteinase‐like activity, equivalent to 4 × 10−6 mg of chymotrypsin per mg of axoplasmic protein. The enzyme was active at physiological pH and ionic strength. Activity was completely inhibited by 1 mM‐para‐hydroxymercuribenzoate and was enhanced by divalent metal cations, especially Ca2+. Axoplasm also exhibited proteinase activity at pH 4.8. Both neutral and acid proteinase like activities were also present in the axonal sheath containing Schwann cells, but their specific activities relative to those in the axoplasm were different. A physiological role, related to the axoplasmic flow of protein, is discussed for the axoplasmic neutral proteinase‐like activity.
EFFECTS OF POTASSIUM AND GLUTAMATE ON BRAIN CORTEX SLICES: UPTAKE AND RELEASE OF GLUTAMIC AND OTHER AMINO ACIDS
Authors: Arnfred T , Hertz L
Published: October 2006

Abstract— Effects of an increased concentration of K+ (55 mm) in the medium on fluxes of glutamate and other amino acids in the presence and absence of 10 mm‐glutamate were studied. The following observations were made:

(1) The efflux of glutamate is slightly increased by excess K+. The glutamate efflux is smaller than the potassium fluxes.

(2) The K+‐induced increase of glutamate efflux is enhanced under anoxia or in glutamate‐containing media.

(3) The influx of glutamate is unaffected or slightly increased by excess K+.

(4) The efflux of GABA is increased by excess K+, both in the absence and in the presence of glutamate.

(5) Efflux of glutamine, leucine and lysine is increased by excess K+, but only provided that glutamate is also present in the medium.

(6) Efflux of glutamate and of GABA is increased by addition of 10 mm‐glutamate.
MEDIATION BY β‐ADRENERGIC RECEPTORS OF EFFECT OF NOREPINEPHRINE ON PINEAL SYNTHESIS OF [14C]SEROTONIN AND [14C]MELATONIN
Authors: Wurtman R. J. , Shein H. M. , Larin F.
Published: October 2006

Rat pineal organs maintained in organ culture converted [14C]tryptophan to [14C]serotonin and [14C]melatonin. The synthesis of both indoles was stimulated by the presence of norepinephrine or dibutyryl adenosine 3′,5′‐monophosphate. This effect of norepinephrine could be blocked by the α‐adrenergic blocking drug, propranolol, but was not modified by the a‐adrenergic blocking agent, phenoxybenzamine. Neither blocking agent modified the pineal response to dibutyryl adenosine 3′,5′‐monophosphate. Unlike dibutyryl adenosine 3′,5′‐monophosphate, the naturally occurring adenosine phosphates did not stimulate synthesis of [14C]melatonin in vitro.
EFFECT OF TETANUS TOXIN ON THE CONTENT OF GLYCINE, GAMMA‐AMINOBUTYRIC ACID, GLUTAMATE, GLUTAMINE AND ASPARTATE IN THE RAT SPINAL CORD12
Authors: Fedinec A. A. , Shank R. P.
Published: October 2006

Tetanus toxin injected intramuscularly induced no significant changes in the levels of glycine, GABA, glutamate, glutamine or aspartate in extracts of spinal cord from rats killed at timed intervals during the development of local and generalized tetanus. The amino acid contents in the hemisegment (longitudinal one‐half) of the spinal cord (L2‐L6) on the injected side (left gastrocnemius muscle) did not differ significantly from the contents in the hemisegment of the spinal cord on the non‐injected side. Nor were there any consistent changes in the contents of the amino acids in either hemisegment of the spinal cord as the tetanic symptoms became progressively more severe. Hence, the amino acid pool in the spinal cord was relatively stable despite the metabolic changes known to occur in tetanus. Our observations are consistent with the view of Johnston, De Groat and CURTIS (1969) who suggested that if glycine were indeed a spinal inhibitory neurotransmitter released by interneurons affected by tetanus toxin, the toxin should interfere with the release of the amino acid rather than deplete the transmitter stores.
GABA UPTAKE IN RAT CENTRAL NERVOUS SYSTEM: COMPARISON OF UPTAKE IN SLICES AND HOMOGENATES AND THE EFFECTS OF SOME INHIBITORS
Authors: Iversen L. L. , Johnston G. A. R.
Published: October 2006

Abstract— Fifty‐two substances were tested as inhibitors of the uptake of [3H]GABA in slices of rat cerebral cortex. Among GABA analogues tested, only the 2‐fluoro, 3‐hydroxy and 2‐amino compounds had affinities for the uptake mechanism comparable to that of GABA. [3H]GABA uptake was also potently inhibited by p‐chloromercuriphenylsulphonate, N‐ethylmaleimide, chlorpromazine and haloperidol. No inhibitors were found to act in a competitive manner with respect to GABA. [3H]GABA uptake was also examined in homogenates of cerebral cortex and other regions of CNS. There was a rapid uptake of [3H]GABA into particles when homogenate samples were incubated with the labelled amino acid; this uptake had similar kinetic properties and inhibitor sensitivity to that observed in slices of intact tissue. Density gradient centrifugation experiments indicated that the particles responsible for the uptake of [3H]GABA in homogenates were probably synaptosomes. Uptake of [3H]GABA also occurred in slices and homogenates of rat spinal cord, and evidence was obtained by the simultaneous labelling of homogenates with [14C]glycine and [3H]GABA that these two amino acids were taken up by different nerve terminals in this region.
CAPACITIES FOR BINDING AMINO ACIDS BY tRNAs FROM RAT BRAIN AND THEIR CHANGES DURING DEVELOPMENT
Authors: Barra H. S. , Uñates Lilia E. , Sayavedra Marta S. , Caputto R.
Published: October 2006

Abstarct

–The total tRNA and some specific tRNAs from the 100,000g soluble fraction of rat brain were measured during development (postnatal ages 4–55 days). For determination of specific tRNAs we developed a method that measured their capacities to bind specific amino acids. Levels of total tRNA were decreased in the soluble fraction from the brains of 55‐day‐old rats in comparison to those for the 4‐day‐old rats. The aminoacylation capacities of tRNAs for phenylalanine, lysine, proline, valine, leucine, alanine and isoleucine were diminished in the 55‐day‐old rats in comparison to those for 4‐day‐old rats when expressed per unit wet weight of brain. When the 4‐ to 55‐day changes in aminoacylation capacity of each specific tRNA was expressed relative to that of the total tRNA, tRNAPhe and tRNALysLys were diminished; tRNAPro, tRNAVel, tRNAGIY and tRNALeu showed no significant changes; and tRNAA1a and tRNAIle were increased. Incorporation of amino acids into a material insoluble in hot TCA (probably proteins) in a ribosome‐free system occurred in the brain preparations. Out of ten different amino acids studied, arginine and tyrosine exhibited the highest values for this type of transfer.
NEUROCHEMICAL PROPERTIES OF ADRENERGIC NERVES REGENERATED AFTER 6‐HYDROXYDOPAMINE
Authors: Jonsson Gösta , Sachs Charlotte
Published: October 2006

Abstract— The uptake‐storage properties and synthesis of noradrenaline, and fluorescence morphology of adrenergic nerves which have been allowed to regenerate for 4 weeks after a chemical sympathectomy produced by 6‐hydroxydopamine have been investigated in mouse iris and atrium. The regenerated nerve terminals displayed a lower formaldehyde‐induced fluorescence intensity whereas the non‐terminal axons exhibited a stronger fluorescence intensity and a more beaded appearance compared with mature nerves. The endogenous noradrenaline concentration after 6‐hydroxydopamine was 30% in iris and 45% in atrium compared to control values. Recovery of [3H]noradrenaline uptake was found to be more rapid than that of endogenous noradrenaline concentration after the 6‐hydroxydopamine treatment. [3H]Noradrenaline uptake in regenerating and adult mature nerves both obeyed Michaelis‐Menten kinetics having identical Km values. There was a close correlation between [3H]noradrenaline uptake and nerve density of adrenergic nerves regenerated after 6‐hydroxydopamine. These results show that [3H]noradrenaline uptake is a better index for the number of regenerated nerve terminals than is the endogenous noradrenaline concentration. The retention of [3H]noradrenaline taken up and accumulated in vitro was about the same in regenerated and mature nerves, although a slight tendency to less effective retention was observed in the regenerated nerves. Subcellular distribution studies showed that relatively less [3H]noradrenaline was recovered in the microsomal fraction after 6‐hydroxydopamine treatment. The formation of 14C‐labelled catecholamines from [14C]DOPA was higher in regenerating nerves than indicated by the endogenous noradrenaline concentration but lower than that indicated by the [3H]noradrenaline. It is concluded that the regenerating nerves contain less endogenous noradrenaline than adult mature nerves and that the uptake mechanism develops promptly, whereas the development of the storage mechanism lags behind.
FAST AXOPLASMIC TRANSPORT OF ACETYLCHOLINESTERASE IN MAMMALIAN NERVE FIBRES
Authors: Ranish N. , Ochs S.
Published: October 2006

Abstract— Acetylcholinesterase (acetylcholine acetyl‐hydrolase, EC 3.1.1.7) is carried down mammalian nerve fibres by the fast axoplasmic transport system. This conclusion was derived from experiments involving the ligation of cat sciatic nerves at two sites placed 83.5 mm apart. The enzyme accumulated in segments of nerve proximal to the upper ligation in a linear fashion over a period of at least 20 h. At approximately 5 h the accumulation of enzyme ceased in the nerve segment proximal to the distal ligation within the isolated length of nerve, an observation indicating that the portion of AChE free to move within the isolated nerve had been depleted during this period of time. The freely moving fraction of AChE was estimated to be 15% of the total enzyme activity present in the nerve (10% in the proximo‐distal direction and 5% in the retrograde direction). The rate of AChE downflow (as estimated from the intercept of the curve plotting accumulation with the line denoting when depletion started) was 431 mm/day within a 95% confidence interval of 357–543 mm/day. In view of the variability, our results demonstrated that AChE was being carried by the fast axoplasmic transport system, which in earlier studies was estimated to have a characteristic rate close to 410 mm/day.

An accumulation of AChE was also found on the distal side of the ligations that represented a movement of AChE in the distal‐proximal direction in the fibres. This retrograde transport was smaller in amount (about one‐half) than the proximo‐distal rate of transport, or close to 220 mm/day. The rate of AChE transport was discussed in relation to the ‘transport filament’ hypothesis of fast axoplasmic transport.
FREE AMINO ACIDS AND RELATED COMPOUNDS IN FIVE REGIONS OF BIOPSIED CAT BRAIN
Authors: Perry T. L. , Sanders H. D. , Hansen Shirley , Lesk Donna , Kloster Marlene , Gravlin Linda
Published: October 2006

Abstract— Contents (μmol/g wet wt.) of 34 free amino acids and related compounds were measured in grey matter from three areas of cerebral cortex, from the cerebellum, and from the caudate nucleus in unanaesthetized cats with classical cerveau isolé preparations. Brain specimens were frozen in liquid nitrogen within 10 s of removal; thus, the values found were expected to approximate those which occur in living cat brain. Levels of most of the compounds measured were lower than those previously reported for the cat. In the case of GABA, alanine, and ethanolamine, the lower values found seemed attributable to the rapid freezing of brain tissue, and may more closely approximate levels occurring in living cat brain. On the other hand, the relatively low levels of aspartic and glutamic acids found may have resulted from use of the cerveau isolé preparation. Little difference in levels of amino compounds was found among the three cerebral cortical areas examined. However, there were significant differences in the contents of a number of amino acids between cerebral cortex and the cerebellum or caudate nucleus. These differences resembled those previously observed in autopsied human brain. The content of GABA was two‐fold higher in biopsied cat cortex than in biopsied human cortex, whereas the content of cystathionine was only 10 per cent of that in human cortex. Homocarnosine and α‐(γ‐aminobutyryl)‐lysine, two GABA‐containing dipeptides found in relatively large amounts in human brain, were not detectable in cat brain. Living cat brain contained two amino acids not previously reported for this species:putreanine and ɛ‐N‐methyllysine.
EFFECTS OF ACETYLCHOLINE ON THE INCORPORATION OF [32P]ORTHOPHOSPHATE IN VITRO INTO THE PHOSPHOLIPIDS OF NERVE‐ENDING PARTICLES FROM GUINEA PIG BRAIN
Authors: Yagihara Y. , Hawthorne J. N.
Published: October 2006

Abstract— Guinea pig brain nerve‐ending particles (synaptosomes) were incubated with [32P]orthophosphate in a medium with or without 10−4M‐acetylcholine and 10−4 M‐eserine. Phospholipids were then extracted and separated by chromatography. About 60 per cent of the 32P was found in phosphatidic acid and about 20 per cent in triphosphoinositide. Acetylcholine significantly increased the specific radioactivity of phosphatidic acid but had no effect on that of phosphatidylinositol or the nucleotide fraction. Labelling of the other phospholipids, including diphosphoinositide and triphosphoinositide, was not altered significantly by acetylcholine. Labelling of the nucleotide fraction and the polyphosphoinositides reached a peak at 40 min, that of phosphatidic acid at 80 min, while that of phosphatidylinositol was still rising at 160 min.
A TECHNIQUE FOR MEASURING BRAIN PROTEIN SYNTHESIS
Authors: Garlick P. J. , Marshall I.
Published: October 2006

Abstract— Mice were infused intravenously for varying periods of time with L‐[U‐14C]‐ tyrosine. The specific activity of free tyrosine in the blood and the brain, and of protein‐bound tyrosine in the brain, was measured and the mean rate of protein synthesis calculated. The half‐life of mixed brain proteins was found to be close to 4 days with infusions lasting 0.5–2 h.

The origin of the intracellular tyrosine pool was investigated and it was shown that 60 per cent of this was derived directly from the plasma tyrosine and 40 per cent from protein breakdown within the tissue.
The presence of 2′, 3′‐cyclic AMP 3′‐phosphohydrolase in glial cells in tissue culture
Authors: Zanetta J. P. , Benda P. , Gombos G. , Morgan I. G.
Published: October 2006

Abstract— The Enzyme 2′, 3′‐cyclic AMP 3′‐phosphohydrolase (CNP) is regarded as a marker for myelin (KURI‐ HARA and MANDEL, 1970) on the basis of its regional and subcellular distribution (Kurihara and Tsukada, 1967), its ontogenetic characteristics (KURIHARA and TSUKADA, 1968), and its behaviour in two strains of myelin‐deficient mutant mice (Kurihara, Nussbaum and Mandel, 1969). However we have isolated highly‐purified preparations of neuronal plasma membrane from rat brain synaptosomes which contain this enzyme activity (Morgan, Wolfe, Mandel and Gombos, 1971). Two explanations of this finding are possible. The activity could be due to the presence of myelin, but this explanation is ruled out by electron microscopy and by the low level of cerebrosides in the synaptosomal plasma membrane preparations. Myelin is extremely rich in cerebrosides (norton and Autilio, 1966). The second possibility is that the enzyme, 2′, 3′‐cyclic AMP 3′‐phosphohyrolase, may also be found in the glial cells from which myelin is derived (Bunge, Bunge and Pappas, 1962). To test our hypothesis that 2′, 3′‐cyclic AMP 3′‐phosphohydrolase is not a specific marker for myelin, but is also found, in glial cells, we have examined a tumoral glial cell line maintained in myelin‐free tissue culture.
EFFECTS OF SURGICAL DECENTRALIZATION AND NERVE GROWTH FACTOR ON THE MATURATION OF ADRENERGIC NEURONS IN A MOUSE SYMPATHETIC GANGLION
Authors: Black I. B. , Hendry I. A. , Iversen L. L.
Published: October 2006

Abstract— The increase in tyrosine hydroxylase activity in mouse superior cervical ganglion during postnatal development was prevented by administration of the protein synthesis inhibitor cycloheximide. Surgical section of the preganglionic nerves in 4‐day‐old mice prevented the normal increases in tyrosine hydroxylase and monoamine oxidase activity in the ganglion during development. Surgical decentralization also prevented the developmental increases in ganglion size and cell numbers. The preganglionic fibres thus appear to exert a general regulatory effect on the growth and biochemical maturation of postganglionic adrenergic neurons in sympathetic ganglia. Administration of nerve growth factor to young mice failed to eliminate the differences in ganglion size, cell numbers and tyrosine hydroxylase activity between normally innervated and decentralized ganglia. Nerve growth factor, however, caused an increase in all these parameters in both control and decentralized ganglia–the magnitude of these increases being greatest in the control ganglia. Administration of carbachol and physostigmine to neonatal mice did not influence the normal development of tyrosine hydroxylase activity in the superior cervical ganglion.
SPHINGOGLYCOLIPIDS IN THE NERVOUS SYSTEM IN FABRY'S DISEASE
Authors: Miyatake T. , Ariga T.
Published: October 2006

Abstract— Two glycolipids, accumulated in the spinal ganglia of a patient with Fabry's disease were identified as: galactosyl (α1 → 4) galactosyl (β1 → 4) glucosyl(1 → 1) ceramide (CTH) and galactosyl (α1 → 4) galactosyl(1 → 1) ceramide (CDG). Only one glycolipid which had the same structure as the CTH in the spinal ganglia accumulated in the sympathetic ganglia of the patient. In the nervous system, CTH contained behenic acid (C22:0) as the major fatty acid. In the spinal ganglia, CDG also contained behenic acid as the major fatty acid.
EVIDENCE THAT METHADONE BLOCKS DOPAMINE RECEPTORS IN THE BRAIN
Authors: Sasame H. A. , Perez‐Cruet J. , Di Chiara G. , Tagliamonte A. , Tagliamonte P. , Gessa G. L.
Published: October 2006

Abstract— This study has shown that methadone shares with phenothiazine and butyro‐phenoneneuroleptics several pharmacological and biochemical actions:thus, D,L‐methadone causes catalepsy and hypothermia, blocks apomorphine‐induced gnawing, increases brain homovanillic acid levels and stimulates brain dopamine synthesis. The dextro isomer of methadone is inactive. α‐Methyl‐tyrosine potentiates and apomorphine reverses methadone‐induced catalepsy. The data suggest that methadone, like butyrophenone and phenothiazine neuroleptics, blocks dopamine receptors in brain.
EFFECTS OF IMMOBILIZATION AND FOOD DEPRIVATION ON RAT BRAIN TRYPTOPHAN METABOLISM
Authors: Curzon G. , Joseph M. H. , Knott P. J.
Published: October 2006

Abstract— Withdrawal of food or immobilization both led to changes in rat brain tryptophan metabolism. Brain tryptophan and 5‐hydroxyindolylacetic acid concentrations both increased while changes in 5‐hydroxytryptamine were much smaller. Changes were greater upon withdrawal of food. The brain tryptophan change did not appear merely to reflect an overall increase of brain amino acid concentrations, brain tyrosine concentration being only slightly increased by food withdrawal and significantly decreased upon immobilization. Plasma tryptophan did not increase. The changes in brain indole metabolism were not abolished by adrenalectomy. Results are discussed in relation to the regulation of brain serotonin metabolism.
THE PRESENCE OF BIOLOGICALLY LABILE COMPOUNDS DURING ISCHEMIA AND THEIR RELATIONSHIP TO THE EEG IN RAT CEREBRAL CORTEX AND HYPOTHALAMUS
Authors: Swaab D. F. , Boer K.
Published: October 2006

—Two surgical methods are described in the present paper, allowing for the approximate determination of in vivo levels of ATP, lactate, glucose, pyruvate and glycogen in anatomically uninjured cortex and hypothalamus from unanaesthetized rats. It was not possible to obtain such levels for P‐creatine in the 2 mm thick samples used in the present investigation. No fundamental difference was observed between the cortical and the hypo‐thalamic levels of these substrates nor in their fluxes.

The substrate fluxes during ischemia were correlated with electrical activity in the rat cortex and hypothalamus, recorded by means of telemetrically transmitted electroencephalograms. The electrical activity declined precipitously at 9.6 s after decapitation in the cortex, and after 12.1 s in the hypothalamus. High levels of glycogen, glucose and ATP were present at this moment, while P‐creatine had declined sharply.
THE EFFECT ON GABA METABOLISM IN BRAIN OF ISONICOTINIC ACID HYDRAZIDE AND PYRIDOXINE AS A FUNCTION OF TIME AFTER ADMINISTRATION
Authors: Wood J. D. , Peesker S. J.
Published: October 2006

—The effect of intramuscularly administered INH on brain levels of GABA in chicks was dependent on the amount injected. A subconvulsant dose of INH (1·1 mmol/kg) produced a slow steady decline in the level of GABA, whereas a convulsant dose (2·19 mmol/kg) brought about a sequential fall and rise in GABA level. This sequence of events reflected changes in the relative activities of GAD and GABA‐T brought about by the hydrazide. The administration of pyridoxine together with the INH (2·19 mmol/kg) prevented the onset of seizures and lessened the effect of the INH on GABA levels and GAD activity but not on GABA‐T activity. The possibility that a deranged GABA metabolism is responsible for hydrazide‐induced seizures is discussed.
REMOVAL AND UTILIZATION OF KETONE BODIES BY THE BRAIN OF NEWBORN PUPPIES
Authors: Spitzer J. J. , Weng J. T.
Published: October 2006

The removal of circulating ketone bodies by the brain was investigated in 0‐ to 8‐day‐old puppies under pentobarbital anaesthesia. Of the arterial acetoacetate (AcAc) and β‐hydroxybutyrate (βOHB), 24 and 30 per cent, respectively, were removed by the brain. There was a direct correlation between the arterial concentrations of either AcAc or βOHB and the A‐V difference of the respective ketone body across the brain. When a continuous infusion of Na‐dl‐3‐hydroxybutyrate [3‐14T] was administered for more than 2 h, labelling of both phospholipids and free cholesterol was consistently observed in all six areas of the brain that were sampled. We conclude that the removal and utilization of ketones is of physiological importance in the brain of newborn animals.
TEMPERATURE AND INHIBITOR EFFECTS ON FAST AXONAL TRANSPORT IN A MOLLUSCAN NERVE
Authors: Heslop J. P. , Howes Elizabeth A.
Published: October 2006

—The cerebro‐visceral connective of Anodonta cygnea has been shown to provide a convenient system for experiments on fast axonal transport. The transport mechanism is directional, independent of the cell bodies, inhibited by cyanide, dinitrophenol and colchicine but is resistant to anoxia. Although the rate of transport increases with temperature above 15°C it is more or less temperature‐independent from 4 to 15°C, i.e. over the normal temperature range of this pond‐dwelling mollusc.
LIPID COMPOSITION OF QUAKING MOUSE MYELIN: COMPARISON WITH NORMAL MOUSE MYELIN IN THE ADULT AND DURING DEVELOPMENT1
Authors: Baumann N. , Bourre J. M. , Jacque C. , Harpin M. L.
Published: October 2006

Abstract— In the ‘Quaking’ mouse, a deficiency in the long chain fatty acid content of galactolipids has been shown to occur.

Myelin in the mutant has been compared to myelin in adult and in 12‐day‐old controls. We have shown that myelin is not only quantitatively reduced but also qualitatively modified, with a higher protein and a lower galactolipid content. Cerebrosides contain only a small amount of kerasin, lacking long chain nonhydroxylated fatty acids in comparison to both controls; the relative percentage of phrenosin is increased.

Although many similarities exist between adult Quaking myelin and myelin at 12 days, differences have been shown to occur which may be in relation to a genetic block at an earlier stage of development.
Low molecular weight constituents of cerebrospinal fluid: N‐benzoylglycine (hippuric acid)
Authors: Couch Margaret W. , Greer M. , Scott K. N. , Williams C. M.
Published: October 2006

When examined by gas chromatography, methylated acid extracts of cerebrospinal fluid (CSF) contain large numbers (20–40) of constituents ranging in concentration from about 1 to 30 μg/ml. We have recently undertaken the identification of these constituents by the use of chemical ionization mass spectrometry and electron impact mass spectrometry as primary tools. In this paper we report the identification in CSF of N‐benzoylglycine (hippuric acid), an acid not hitherto reported in CSF.
EFFECTS OF AMINO ACIDS ON THE ISOLATED CHICKEN RETINA, AND ON ITS RESPONSE TO GLUTAMATE STIMULATION1
Authors: Van Harreveld A. , Fifkova Eva
Published: October 2006

Abstract— The effect of a number of amino acids on the transparency and on the release of of [14C]glutamate from isolated chicken retinae charged with this compound was investigated. Also the effect of various amino acids on the response of the retina to stimulation with unlabelled glutamate, which causes an increase in transparency and a release of the label, was examined. In parallel experiments the effect of these same amino acids on the transparency and spreading depression (SD) was investigated in preparations consisting of the posterior part of the eye. A number of amino acids such as L‐leucine, L‐phenylalanine, L‐tryptophan, L‐lysine, L‐histidine, L‐arginine and others had little or no effect on these preparations. DL‐valine and DL‐homoserine caused an increase in transparency but no release of the label and did not affect the response to glutamate. Another group of amino acids comprising DL‐a‐alanine, L‐serine, L‐threonine, L‐proline and glycine also caused an increase in the transparency of the retina without a release of labelled glutamate, but prevented the increase in transparency resulting from glutamate stimulation without affecting the release of the label. A final group of amino acids which included L‐glutamic acid diethyl ester, DL‐a‐methyl glutamate, L‐glutamine, L‐asparagine, DL‐homocysteate and L‐cysteine caused a change in transparency of the retina accompanied by a release of the label; they prevented the change in transparency as well as the release of the label during stimulation by glutamate. Some amino acids, L‐serine, L‐threonine, DL‐a‐methyl glutamate, L‐asparagine, DL‐homocysteate and L‐cysteine, caused wrinkling and folding of the retinae which furthermore became opaque. Of the amino acids investigated, proline gave promise of being a practical antagonist to the action of glutamate on the retina.
THE FREE AMINO ACIDS IN PERIPHERAL NERVES AND IN ISOLATED INHIBITORY AND EXCITATORY NERVE FIBRES OF CANCER MAGISTER1
Authors: Sorenson Martha M.
Published: October 2006

Abstract— Free amino acids in whole nerve and in excitatory and inhibitory fibres isolated from the walking legs of the crab, Cancer mgister, have been determined, using a densitometric method which permits quantitative estimates of 1 nmol of a ninhydrin‐positive substance on paper chromatograms. In confirmation of previous reports, whole nerve contained 5 amino acids at levels greater than 10 mmol/kg wet wt., including two anions (glutamate and aspartate) of major importance. The concentrations of 12 other amino acids were also estimated. The free amino acid fraction contributed about 40% (415 mosmol/kg of cell water) to the osmotic concentration of the tissue. Isolated inhibitory fibres were distinguished by a 15‐fold higher level of GABA than that found in excitatory fibres (46 vs 3·1 mmol/l. of axoplasm). The level of proline also differed in the two types of fibres, but in contrast to GABA it was less concentrated in inhibitory fibres. As a consequence of these and of other smaller differences, the total concentration of free amino acids was slightly less in inhibitory fibres (365 vs 405 mmol/l. of axoplasm in excitatory fibres). The demonstration of the presence of GABA in crab inhibitory axons supports earlier suggestions that it may be the inhibitory transmitter at crab neuromuscular junctions.