bluuebunny/crossref_metadata_2025 huggingface dataset:
TETANUS TOXIN AND AMINO ACID LEVELS IN CAT SPINAL CORD
Authors: Johnston G. A. R. , de Groat W. C. , Curtis D. R.
Published: October 2006

Abstract— —The levels of the depressant amino acids found in appreciable amounts in cord extracts—α‐alanine, cystathionine, GABA, glycine and serine—were not significantly influenced by tetanus toxin. This supports the view that the antagonism of spinal inhibition by the toxin is the result of an interference with transmitter release rather than a reduction in the amount of transmitter available for release.

The marked increase in aspartic acid levels found in the spinal cord after treatment with tetanus toxin may reflect the association of aspartic acid with the increased activity of spinal excitatory interneurones or the involvement of aspartic acid as a glycine precursor in spinal tissue.
A STUDY OF LIPID COMPONENTS IN BRAIN OF THE ‘JIMPY’ MOUSE, A MUTANT WITH MYELIN DEFICIENCY
Authors: Nussbaum J. L. , Neskovic N. , Mandel P.
Published: October 2006

Abstract—

(1) Brain composition and developmental changes were investigated in a mutant (‘Jimpy’) mouse characterized by a severe myelin deficiency.

(2) Significantly lower cholesterol, phospholipid and galactolipid values were observed, and the accumulation of these lipids during the myelination period was markedly reduced or absent.

(3) The most remarkable feature of ‘Jimpy’ brain was a very small galactolipid content. In 29‐day‐old mutants the concentration of galactolipids was 0‐18 μ moles/g wet wt., representing a 46‐fold decrease when compared to values determined in normal mice.

(4) There was no such striking change in the distribution of different phospholipids. However, lowered relative amounts of some phospholipids, e.g. ethanolamine plasmalogen, sphingomyelin and phosphatidylserine, were observed in ‘Jimpy’ brain.

(5) Protein content was also lower in mutant brains and showed an absolute decrease after 23 days of life.

(6) These data support the statement that the process of myelination is disturbed at an early stage, resulting in a deficiency of mature myelin sheaths and leading probably to the breakdown of primitive myelin structures.
COMPARISON OF CEREBRAL REGIONAL METABOLISM OF [14C]LEUCINE FOLLOWING THIRD VENTRICLE AND INTRAVENOUS ADMINISTRATION IN THE CAT
Authors: Berl S. , Frigyesi T. L.
Published: October 2006

Abstract— In the cat, intraventricularly injected [14c]leucine does not appear to penetrate into the cerebral tissue, whereas intravenously injected [14c]leucine readily penetrates the blood‐brain barrier. The latter route of administration of [14c]leucine produces rather uniform distribution of radioactivity in cortical and subcortical regions as well as diencephalic, lower brain stem, and cerebellar regions. Data consistent with compartmentation of the glutamate‐glutamine system were observed in all regions except the cerebellum and head of the caudate nucleus. In the latter two areas, the ratios of the specific activity of glutamine to glutamic acid was less than 1, whereas in all other areas it was greater than 1. The turnover rate of the brain protein was fastest in the cerebellum and neocortex and slowest in the caudate nucleus and in the pons and medulla.
METABOLISM OF GLUCOSE AND REDUCTION OF RETINALDEHYDE IN RETINAL PHOTORECEPTORS1
Authors: Futterman S. , Hendrickson Anita , Bishop P. E. , Rollins Martha H. , Vacano Elsi
Published: October 2006

—The capacity of a variety of substrates to support reduction of retinaldehyde to retinol by preparations of outer segments from photoreceptor cells of bovine retina, the requirement for supplements, the effect of iodoacetate, and the stoichiometry of the metabolism of glucose and the reduction of retinaldehyde have been studied. Metabolism of glucose supported reduction of retinaldehyde by preparations of outer segments at approximately the rate observed for the intact retina. Throughout the physiological range of pH, the dehydrogenase reactions of the pentose cycle in outer segments provided virtually all of the reduced pyridine nucleotides that were utilized for reduction of retinaldehyde. It was concluded that reduction of retinaldehyde during light adaptation is exclusively dependent upon NADPH.
ON THE ORIGIN OF THE ACETYL MOIETY OF ACETYLCHOLINE IN BRAIN STUDIED WITH A DIFFERENTIAL LABELLING TECHNIQUE USING 3H‐14C‐MIXED LABELLED GLUCOSE AND ACETATE
Authors: Sollenberg J. , Sörbo B.
Published: October 2006

—Cortex slices of rat brain were incubated with glucose mixed‐labelled with 3H and 14C in the 6‐position and the 3H/14C ratios of lactate, acetate, citrate and acetylcholine were determined. The values obtained were: lactate 0·95, acetate 0·85, citrate 0·65 and acetylcholine 0·67 when expressed in relation to a glucose 3H/14C ratio of 1·00. When brain slices were incubated with [2‐14C, 2‐3H]acetate in the presence of unlabelled glucose, labelled acetylcholine was formed with a 3H/14C ratio not significantly different from the labelled substrate. The results indicate that citrate is a precursor to the acetyl moiety of acetylcholine.
LEVELS OF MYO‐INOSITOL IN NORMAL AND DEGENERATING PERIPHERAL NERVE1
Authors: Kusama H. , Stewart M. A.
Published: October 2006

—Free inositol was measured in peripheral nerves of the monkey, rabbit, rat, frog and lobster; levels in mammalian nerve were similar, and two to three times greater than in the other species. Concentrations of myo‐inositol in rabbit tibial nerve increased from proximal to distal segments; in optic nerve the concentrations decreased with greater distance from the retina. In the early stages of Wallerian degeneration rabbit tibial nerve contained 25 per cent less free myo‐inositol, rat nerve 50 per cent less. Rabbit nerves were analysed at 2 and 5 weeks after section; by 5 weeks levels of myo‐inositol had increased to 50 per cent above normal. Similar changes were found in degenerating rabbit optic nerve. The combination of galactose feeding and nerve section resulted in reduction of the myo‐inositol in rat sciatic nerve to one‐fifth of the control value; galactitol in the nerve decreased by 50 per cent after section. The evidence suggests that myo‐inositol in nerve is located mainly in Schwann cells or glia.
BASE‐EXCHANGE REACTIONS FOR THE SYNTHESIS OF PHOSPHOLIPIDS IN NERVOUS TISSUE: THE INCORPORATION OF SERINE AND ETHANOLAMINE INTO THE PHOSPHOLIPIDS OF ISOLATED BRAIN MICROSOMES1,2
Authors: Porcellati G. , Arienti G. , Pirotta M. , Giorgini D.
Published: October 2006

Abstract— The calcium‐dependent incorporation of l‐[3‐3H]serine and [1,2‐14C]ethanol‐amine into the phospholipid of isolated subcellular fractions from chick brain was studied and the properties of incorporation were examined. The microsomal fraction was found to possess the highest rate of incorporation and was able to convert under optimal conditions about 120 nmol of labelled serine and 220 nmol of ethanolamine/g of fresh brain microsomes/h. The requirement for Ca2+ ion appeared to be absolute. Mg2+ ion caused a gradual reduction in the existing enzymic activity, only when pre‐incubated with microsomes and labelled bases before adding Ca2+ ion. The incorporation of serine and ethanolamine was actively inhibited by Hg2+, Co2+, Cu2+ and Mn2+ ions, and was abolished by ethylenediamine tetra‐acetate treatment. Ethanolamine, but not choline, inositol or carnitine, competitively inhibited serine incorporation, while d‐serine had slight effect. Conversely, l‐serine inhibited competitively the incorporation of ethanolamine.

The greater part of the incorporated serine (85 per cent) was localized in microsomal phosphatidylserine, while a small percentage was found in phosphatidylethanolamine. Similarly, 90 per cent of the incorporated ethanolamine was confined to phosphatidylethanolamine and a small percentage was found in the plasmalogen derivative. The mechanism of serine and ethanolamine incorporation was investigated. The results are compared with those published for similar mammalian and non‐mammalian systems.
THE SUBCELLULAR LOCALIZATION OF HISTAMINE AND HISTAMINE METHYLTRANSFERASE IN RAT BRAIN1
Authors: Kuhar M. J. , Taylor K. M. , Snyder S. H.
Published: October 2006

Abstract— We have examined the subcellular localization of histamine and histamine methyl‐transferase (S‐adenosylmethionine: histamine 7V‐methyltransferase; EC 2.1.1.8) in rat brain. The highest levels of histamine and histamine methyltransferase activity were found in the hypothalamus. A large proportion of hypothalamic histamine and histamine methyltransferase activity was found in particles with sedimentation properties in sucrose gradients similar to synaptosomes storing norepinephrine and serotonin. Histamine displayed a bimodal distribution in sucrose gradients. A substantial amount of a tracer dose of [3H]histamine added to hypothalamic homogenates at 4°C was bound to particulate fractions, suggesting that endogenous histamine may redistribute and bind to subcellular fractions during homogenization. The second, lighter peak of histamine in sucrose gradients was thought to be due to histamine that redistributed during homogenization.
GLYCINE UPTAKE IN RAT CENTRAL NERVOUS SYSTEM SLICES AND HOMOGENATES: EVIDENCE FOR DIFFERENT UPTAKE SYSTEMS IN SPINAL CORD AND CEREBRAL CORTEX
Authors: Johnston G. A. R. , Iversen L. L.
Published: October 2006

Abstract— Evidence is presented that glycine is taken up by two different transport systems in rat CNS tissue slices; one system has relatively low affinity for glycine (Km= 300 μm) and predominates in cerebral cortex, cerebellum and mid‐brain, the other has a higher affinity for glycine (Km= 40 μm) and is detectable only in spinal cord, medulla and pons. The low affinity transport system appears to be shared by other small neutral amino acids, whereas the high affinity system is very specific for glycine. Both transport systems were shown to be present in particles in homogenates of CNS tissue by incubation with glycine in vitro, and subcellular fractionation studies suggested that synaptosomes were partly responsible for such uptake. Various substances were tested as inhibitors of the high affinity uptake system for glycine in spinal cord slices; the most potent inhibitors were p‐chloro‐mercuriphenylsulphonate, N‐ethylmaleimide, chlorpromazine, imipramine, desipramine, hydrazinoacetic acid and haloperidol. No competitive inhibitors of the high affinity glycine uptake were found. It is suggested that the high affinity transport system is associated with inhibitory synapses where glycine is a transmitter.
THE FORMATION OF CHOLINE AND OF ACETYLCHOLTNE BY BRAIN IN VITRO
Authors: Collier B. , Poon P. , Salehmoghaddam S.
Published: October 2006

Abstract— Free choline and acetylcholine (ACh) in mouse or rat brain were assayed biologically. The subcellular distribution of ACh in brain slices that had been incubated in the presence of eserine was compared to that in control brain; during incubation, the ACh outside nerve endings increased four‐fold, the ACh released from synaptosomes by osmotic shock doubled but the ACh bound firmly within nerve endings did not increase. The two nerve ending stores of ACh were labelled to similar specific radioactivities when slices were incubated with [3H]choline, but the specific radioactivity of the ACh formed was much lower than that of the added choline. Tissue incubated in the presence of eserine released choline and ACh into the medium and the tissue levels of both substances increased. Brain tissue exposed to Na+‐free medium lost 84 per cent of its ACh and 66 per cent of its free choline; the amounts of both substances returned towards control values during subsequent incubation in a normal‐Na+ medium (choline‐free). Both the ACh outside nerve endings and the ACh associated with synaptosomes were depleted when tissue was incubated in Na+‐free medium.
DEVELOPMENT AND CHARACTERISTICS OF THE HISTAMINE‐INDUCED ACCUMULATION OF CYCLIC AMP IN THE RABBIT CEREBRAL CORTEX
Authors: Palmer G. C. , Schmidt M. J. , Robison G. A.
Published: October 2006

Abstract— In slices of adult rabbit cerebral cortex histamine at 5 μM produced a detectable rise in adenosine 3′,5′‐monophosphate (cyclic AMP). A maximum (20‐fold) increase was observed in response to 0–5 mM histamine, with higher concentrations being less effective. The antihistaminic agent, tripelennamine, inhibited the response to 50 μM histamine in a dose‐related manner. No effect on basal levels of cyclic AMP was noted with the highest dose of tripelennamine. The cyclic AMP response to 50 μM histamine was sustained for up to 1 h of incubation whether the slices and included medium were assayed together or the slices were assayed separately, although after 60 min of incubation cyclic AMP levels were higher when the medium was included in the assay. During development of the rabbit cerebral cortex, the first detectable increase of cyclic AMP in response to histamine occurred at fetal day 25, and from day 28 to birth the response was a 4‐to 5‐fold increase. A maximal (10‐fold) response was observed at 4–8 days postpartum and by 20 days of postnatal age the response had decreased to the adult levels.
CHANGES IN BLOOD FLOW IN THE COMPONENT STRUCTURES OF THE DOG BRAIN DURING POSTNATAL MATURATION
Authors: Kennedy C. , Grave G. D. , Jehle Jane W. , Sokoloff L.
Published: October 2006

Abstract— Blood flow was measured quantitatively in 35 structures of the brains of dogs of various ages from birth to maturity. In general, values were low at birth and rose to maximal levels between 3 and 7 weeks of postnatal age; declines from the peak levels then followed until values characteristic of maturity were attained by 13 weeks of postnatal age. From relatively uniform perfusion rates throughout the brain at birth there gradually emerged a marked heterogeneity, in parallel with the structural and functional maturation and differentiation known to occur in the brain during this period of life. Our observations may reflect the summation of the changes in energy demands associated on the one hand with biosynthetic processes essential for growth and development and with the support for progressively increasing functional activities on the other.
DYNAMICS OF THE REGULATION OF HISTAMINE LEVELS IN MOUSE BRAIN1
Authors: Taylor K. M. , Snyder S. H.
Published: October 2006

Abstract— The intraperitoneal administration of L‐histidine in a dose of 1000 mg/kg increased threefold the whole brain levels of histamine in the mouse. This increase was evident in all brain regions except the medulla oblongata‐pons. The subcellular localization of histamine and histidine was the same in mice administered bhistidine as in salinetreated animals. Cold exposure and restraint further augmented the elevation of histamine elicited by histidine treatment. a‐Hydrazino‐histidine and 4‐bromo‐3‐hydroxybenzyloxyamine (NSD‐1055) but not a‐methyl‐DOPA inhibited histidine decarboxylase [EC 4.1.1.221 activity in mouse brain homogenates and prevented the increase in brain histamine after histidine administration. NSD‐1055 and a‐hydrazino‐histidine also lowered brain levels of histamine by 50 per cent. NSD‐1055 lowered whole brain levels of histamine rapidly, with a half‐life for the depletable histamine pool of about 5 min. Assuming that inhibition of histidine decarboxylase accounted for the reduction in histamine, then the rate of histamine decline reflects the rate of histamine turnover, and our results suggest that a portion of mouse brain histamine turns over quite rapidly. Reserpine lowered brain levels of histamine by about 50 per cent, whereas the antihistaminic agent, dexbrompheniramine, and sodium pentobarbital elevated histamine levels.
METABOLISM OF BRAIN DURING SLEEP AND WAKEFULNESS
Authors: Reich P. , Geyer S. J. , Karnovsky M. L.
Published: October 2006

Abstract— The levels in brain of lactate, pyruvate, creatine phosphate, ATP, ADP and AMP were examined in sleeping and waking adult rats. The animals were monitored electrophysiologically and the biochemical measurements were made after approx. 25 min of sleep or wakefulness. The previous treatment of the animals had a marked effect on the levels of brain metabolites during sleep. In animals not acclimatized to the observation chamber, brain levels of lactate and pyruvate rose during sleep above those in the waking state: creatine phosphate and ATP were depressed somewhat. When the animals were acclimatized by being placed in the observation chamber for at least 2 h on four or more consecutive days prior to the experiment, sleep was accompanied by a depression of brain levels of lactate and pyruvate and slight elevations of brain levels of creatine phosphate and ATP. No significant differences in the EEG recordings were noted between the sleeping rats of the acclimatized and non‐acclimatized groups. These observations on the effect of acclimatization on brain metabolism during sleep may have clinical relevance in man.
GANGLIOSIDES OF THE OPTIC PATHWAY: BIOSYNTHESIS AND BIODEGRADATION STUDIED IN VIVO
Authors: Holm M.
Published: October 2006

Abstract— Rabbits were given an intraocular injection of [3H]acetate and [1‐14C]glucosamine. The two precursors were incorporated into the gangliosides, whose activities were measured in the retina, optic nerve, optic tract and lateral geniculate body. The radioactivities of cerebrosides and ethanolamine and choline phosphoglycerides were also determined. Gangliosides were labelled in all parts of the optic pathway, from both acetate and glucosamine. The precursors seemed to be distributed along the entire pathway shortly after injection. They were not transported with the blood and no ganglioside transport could be shown.
METABOLISM OF ISOLATED RAT BRAIN PERFUSED WITH GLUCOSE OR MANNOSE AS SUBSTRATE1
Authors: Ghosh A. K. , Mukherji B. , Sloviter H. A.
Published: October 2006

Abstract— After isolated rat brain preparations were perfused with fluid containing either mannose or glucose as metabolic substrate, extracts from the rapidly frozen cerebral cortex were prepared and analysed. Brains perfused with mannose contained somewhat lower levels of glucose‐6‐phosphate and fructose diphosphate than those perfused with glucose but the contents of other glycolytic intermediates were quite similar in both groups. The level of mannose‐6‐phosphate was high in brains perfused with either glucose or mannose, but higher in the latter. In both cases, the ratio of mannose‐6‐phosphate to fructose‐6‐phosphate was very high, suggesting that phosphomannose isomerase (EC 5.3.1.8) may be important in the regulation of glycolysis. The levels of adenine nucleotides and creatine phosphate and the redox ratios were not significantly different with mannose as substrate than with glucose. The contents of free amino acids in brains perfused with mannose did not differ significantly from those in brains perfused with glucose. Our results show that mannose is a satisfactory substrate for the brain under these experimental conditions since it maintains the energy reserves and oxidative status of the cerebral tissue and does not alter the levels of amino acids.
DEVELOPMENT OF A CIRCADIAN RHYTHM IN THE ACTIVITY OF PINEAL SEROTONIN N‐ACETYLTRANSFERASE
Authors: Ellison N. , Weller Joan L. , Klein D. C.
Published: October 2006

Abstract— Pineal serotonin N‐acetyltransferase (EC 2.3.1.5) is a neurally regulated enzyme. It is detectable in the rat as early as 4 days prior to birth. A circadian rhythm in enzyme activity appears on the fourth day after birth. It develops most rapidly during the second week and achieves an adult magnitude by the end of the third week at which time nocturnal values are more than 30‐fold greater than daytime values. Norepinephrine, which appears to be the neurotransmitter regulating this enzyme, can cause a 2‐ to 3‐fold stimulation of N‐acetyltransferase in organ cultures of pineal glands from 4‐day‐old animals and a 17‐fold increase in the activity of glands from 15‐day‐old animals. Apparently the norepinephrinesensitive system controlling pineal N‐acetyltransferase activity also develops most rapidly during the first few weeks of life. The circadian rhythm in the activity of serotonin N‐acetyltransferase develops in the pineal glands of both male and female rats at the same rate. A similar rhythm for the enzyme was not observed in twelve other tissues of the rat.
REGIONAL DEVELOPMENT OF CATECHOLAMINE BIBSYNTHESIS IN RAT BRAIN1
Authors: Porcher W. , Heller A.
Published: October 2006

Abstract— The ontogenetic development of norepinephrine and dopamine and their associated biosynthetic and degradative enzymes was investigated in five anatomical regions of the rat brain. Clear regional differences were found in the development of both norepinephrine and tyrosine hydroxylase (EC 1.14.3.1). In the case of both norepinephrine and tyrosine hydroxylase, brainstem structures achieved adult levels well before forebrain structures. The development of DOPA decarboxylase (EC 4.1.1.26), monoamine oxidase (EC 1.4.3.4) and catechol‐0‐methyl transferase (EC 2.1.1.6) did not appear to differmarkedly from area to area. Further analysis of the data revealed that in forebrain structures both the amines and the biosynthetic enzymes developed concurrently. By contrast, in the brainstem structures, there was a dissociation of amine and enzyme development with development of tyrosine hydroxylase, in particular, markedly preceding that of norepinephrine and of DOPA decarboxylase. The bases for both the lower amine levels in the infant brain and the regional developmental differences are discussed in relation to the anatomical organization of the central catecholamine‐containing neurons.
CHARACTERISTICS OF AMINO ACID ACCUMULATION BY SYNAPTOSOMAL PARTICLES ISOLATED FROM RAT BRAIN
Authors: Peterson N. A. , Raghupathy E.
Published: October 2006

—The characteristics of the accumulation of 14 L‐amino acids (Leu, Ileu, Val, His, Tyr, Phe, Gly, Ala, Ser, Thr, Asp, Pro, Arg and Lys) by synaptosomal fractions prepared from rat brains were studied. Distinct differences were observed in the ion requirements for the accumulation of these amino acids. The accumulation of Asp and Pro alone showed a total requirement for Na+; uptakes of the other amino acids were either maximal in Na+‐free media or only partially dependent on the presence of external Na+. With brain maturation, two types of developmental alterations could be distinguished: (1) changes in rates of influx, and (2) changes in the effects of ions. Synaptosomal fractions prepared from brains of immature rats accumulated Leu, Arg and Lys to a greater extent and Val, Tyr, Pro and Asp to a lesser extent than did the fractions prepared from brains of mature animals. The accumulation of Ser and Thr by immature fractions was partially dependent on external Na+, whereas their accumulation by adult fractions was Na+‐independent. These alterations in Na+ requirements coincided with developmental changes in mutual inhibitions of amino acid transport.
ZINC IN MATURING RAT BRAIN: HIPPOCAMPAL CONCENTRATION AND LOCALIZATION1
Authors: Crawford I. L. , Connor J. D.
Published: October 2006

—Alterations in the localization and concentration of zinc in the hippocampus and in other regions of rat brain were studied during postnatal maturation. Histochemical observations indicated increasing levels of zinc in the hippocampal mossy fibre layer at about 20 days of age. Between 18 and 22 days, hippocampal levels of zinc increased by 35 per cent to reach adult levels (121 ng/mg of protein). After subcellular fractionation, more than one‐half of the hippocampal zinc was found in the first pellet (P1; 1085 g– 10 min), where large boutons would be expected. Autoradiographic evidence, revealing the sequential location of positron tracks first in the granular cell layer and later in the mossy fibre layer, raises the possibility of axoplasmic transport of zinc from granule cell perikarya to their terminal boutons. Our data suggest that zinc may be involved in the maturation and function of the mossy fibre pathway.
THE EFFECT OF DEVELOPMENT ON THE GANGLIOSIDES OF RAT AND PIG BRAIN
Authors: Merat A. , Dickerson J. W. T.
Published: October 2006

Abstract— The ganglioside content of the forebrain, brain stem and cerebellum have been studied, in the rat at various ages from 1 day to 27 months, and in the pig at various ages from 93 days gestation to 30 months. Each part of the brain was analysed for total ganglioside NANA and for four major gangliosides (GMl, GD1a, GDlb and GT1 in the nomenclature of Svennerholm, 1963). In the rat forebrain, the concentration of ganglioside NANA rose rapidly between 1 and 21 days after birth, fell to 3 months and subsequently rose to a mature value at 6 months. In the rat cerebellum, the peak concentration was reached at 2 months and the lower adult value at 9 months, whilst in the brain stern, the concentration rose more slowly and had a broad peak from 15 days to 2 months. Values are also given for the changes in the total amounts in each brain part. The changes in the concentrations and total amounts of ganglioside NANA, in the three parts of the pig brain were, on the whole, similar to those in rat brain except that the percentage distribution of the major gangliosides had almost attained the mature pattern at birth. In the forebrain of both species, the disialoganglioside, GD1a, accounted for the highest percentage of the total gangliosides. The results are discussed with respect to their possible structural significance.
Double labelling study of the spreading depression effect on the incorporation of labelled leucine into the proteins of the brain mitochondrial subfractions
Authors: Avaria Lucia Gaete , Křivánek J.
Published: October 2006

Topical application of potassium chloride solutions (above 0·25 M) as well as some other agents onto the surface of the brain cortex provokes typical changes in the basic performance of the brain. Serious impairment of learning as well as depression of spontaneous activity, depolarization of the cortical cells, disappearance of the evoked responses, changes in unit activity and alteration of energy metabolism are among the detectable features of this phenomenon called cortical spreading depression (CSD) by its discoverer LEÃ (1944). For reviews on CSD see Marshall(1959); Burést(1962); Ochs (1962). The inhibitory effect of CSD on the incorporation of the labelled amino acids into the proteins of the rat cerebral cortex has been reported (Ruščák1964; Bennett and Edelman, 1969; Křivánek, 1969, 1970) and the distribution of the effect among the crude subcellular fractions was studied by Křivánek(1970). Possible involvement of macromolecules, particularly proteins in memory formation and storage has been claimed. It was tempting to see whether the proteins of some mitochondrial subfractions namely nerve endings particles and pure mitochondria, could reveal a differential susceptibility to the potassium action which, in vivo, induces such profound changes in the brain cortex function.
PATTERNS OF AMINO ACID RELEASE FROM NERVE‐ENDINGS ISOLATED FROM SPINAL CORD AND MEDULLA
Authors: Osborne R. H. , Bradford H. F. , Jones D. G.
Published: October 2006

The metabolic properties of synaptosomes prepared from the crude mitochondrial and crude nuclear fractions of the medulla/spinal cord were studied. They showed similar properties, glycine being enriched in the latter. The respiration and glycolysis rates were similar to the cortical synaptosomes previously studied. A major difference from cortical synaptosomes was the enrichment of glycine. Medulla/spinal cord synaptosome suspensions and beds responded metabolically to electrical pulses; respiration and lactate production increased by 50 and 25 per cent respectively. Differential release of glutamate, aspartate, GABA and glycine occurred during both electrical stimulation, and when potassium in the medium was increased. Omitting calcium and adding EGTA greatly reduced this response with both forms of stimulation. The electrically induced release of GABA was completely reversible whilst that of aspartate and glycine was only partially reversible. The electrically stimulated release of glycine and other amino acids was reduced in synaptosomes prepared from rats treated intramuscularly with tetanus toxin 15 hr before death. No action of the toxin was seen on synaptosomes incubated with tetanus toxin after preparation.
ENZYMIC AND CEREBRAL METABOLIC EFFECTS OF 2‐DEOXY‐d‐GLUCOSE
Authors: Horton R. W. , Meldrum B. S. , Bachelard H. S.
Published: October 2006

—The time course of effects of 2‐deoxy‐d‐glucose on cerebral glucose metabolism has been studied in vivo and the inhibitory actions of 2‐deoxy‐d‐glucose and 2‐deoxy‐d‐glucose‐6‐phosphate on cerebral glycolytic enzymes in vitro. Mice were given 2‐deoxy‐d‐glucose 3 g/kg intraperitoneally. Blood 2‐deoxy‐d‐glucose/glucose ratio was 2–3 from 5 to 30 min after injection, the hyperglycaemic response to 2‐deoxy‐d‐glucose having been suppressed with propranolol. Maximal cerebral 2‐deoxy‐d‐glucose uptake observed was 1μ11 μmol/g/min between 5 and 10 min after injection. At 10 min brain concentrations of 2‐deoxy‐d‐glucose and 2‐deoxy‐d‐glucose‐6‐phosphate were 5·82 and 3·12 μmol/g. Analysis of the fate of d‐[U‐14C] glucose given subcutaneously 5 min before death showed that glucose uptake was reduced to 40–60 per cent of control from 5 to 30 min after 2‐deoxy‐d‐glucose. However brain glucose concentration rose three to five‐fold 20–30 min after 2‐deoxy‐d‐glucose. The majority of glucose entering the brain after 10 min of 2‐deoxy‐d‐glucose treatment was recovered as glucose. Conversion of brain glucose to other acid soluble components was reduced to 1/3 at 10 min and 1/5 at 20–30 min. Glucose‐6‐phosphate concentration rose from 5 min onwards and was maintained at twice control concentration from 10–30 min. However, because of the rapid entry of 2‐deoxy‐d‐glucose and its conversion to 2‐deoxy‐d‐glucose‐6‐phosphate, the 2‐deoxy‐d‐glucose 6‐P/glucose 6‐P ratio was between 19 and 32. Brain adenosine triphosphate concentration did not change, creatine phosphate concentration fell after 25 min.

Measurement of enzyme activities in cerebral homogenates (using 1 mivs substrate concentration) showed that hexokinase (EC 2.7.1.1) was 40 per cent inhibited by 5 mm‐deoxy‐d‐glucose (but not by 2‐deoxy‐d‐glucose 6‐P). Glucose 6‐P dehydrogenase (EC 1.1.1.49), 6‐phosphogluconate dehydrogenase (EC 1.1.1.43) and phosphoglucomutase (EC 2.7.5.1) were not affected by either 2‐deoxy‐d‐glucose (5 mm) or 2‐deoxy‐d‐glucose 6‐P (5 or 20 mm). Hexose‐phosphate isomerase (EC 5.3.1.9) was 70 per cent inhibited by 20 mm‐d‐deoxy‐d‐glucose 6‐P. Phosphofructokinase (EC 2.7.1.11) was inhibited by 17 per cent by 2‐deoxy‐d‐glucose 6‐P (20 mm). During the initial impairment of cerebral function by 2‐deoxy‐d‐glucose there is competitive inhibition of glucose transport into the brain; later, glycolysis is more powerfully depressed by the inhibition of isomerase produced by the high intracerebral concentration of 2‐deoxyglucose‐6‐phosphate.
DEVELOPMENT OF Na+‐STIMULATED GLUCOSE OXIDATION IN SYNAPTOSOMES1,2
Authors: Diamond I. , Fishman R. A.
Published: October 2006

Abstract— d‐[14C]Glucose was oxidized to 14CO2 by synaptosomes prepared from adult rat brain. Added Na+ stimulated glucose oxidation by 179%, but K+ and choline were without effect. Li+ stimulated glucose oxidation by 64%. Ouabain largely prevented the stimulatory effect of Na+ on glucose oxidation but had no effect in the absence of Na+. 2‐Deoxy‐d‐glucose competitively inhibited glucose oxidation differently at two different ranges of deoxyglucose and glucose concentrations; the Ki was 0.54 and 16 mm, respectively. In the presence or absence of Na+ 2,4‐DNP‐stimulated glucose oxidation by 370% while iodoacetate inhibited glucose oxidation by 87–95%. There was a striking increase in Na+‐stimulated glucose oxidation with development but glucose oxidation in the absence of Na+ did not change dramatically with age.

Taken together the data suggest synaptosomes exhibit coupled respiration which can be modulated by Na+. In addition, the appearance of Na+‐stimulated glucose oxidation with maturation probably is linked to the development of Na+‐K+‐ATPase acitivity in the synaptosomal membrane.
ENZYMIC ACTIVITIES AND SODIUM, POTASSIUM AND COPPER CONCENTRATIONS IN MOUSE BRAIN AND LIVER AFTER CUPRIZONE TREATMENT IN VIVO
Authors: Venturini G.
Published: October 2006

Abstract— The oral administration of cuprizone to mice induces status spongiosus in the CNS and giant mitochondria in the liver. The activities of monoamine oxidase and cytochrome oxidase in brain and liver are inhibited and succinate dehydrogenase activity is increased. There is an increase in sodium and decrease in potassium concentrations; brain dry weight and copper content are decreased. Animals treated with copper‐chelated cuprizone do not show any changes.
UPTAKE AND RELEASE OF [14C]ADENINE DERIVATIVES AT BEDS OF MAMMALIAN CORTICAL SYNAPTOSOMES IN A SUPERFUSION SYSTEM
Authors: Kuroda Y. , McIlwain H.
Published: October 2006

(1) Synaptosomal fractions from guinea pig neocortical dispersions prepared in sucrose solutions were deposited from saline media as ‘beds’ on nylon bolting cloth. When incubated with 0.5–10 μm‐[14C]adenine or adenosine in glucose bicarbonate salines, uptake of 14C from adenosine proceeded at about four times the rate of uptake of [14C]adenine. This contrasted with the relative uptake of the two compounds to neocortical tissue slices or to beds made from mitochondrial fractions, where uptake was similar with the two precursors. Uptake of both precursors to synaptosome beds was much greater than uptake of inosine.

(2) Synaptosome beds, [14C]adenosine‐loaded, contained 88 per cent of the 14C as 5′‐adenine nucleotides, the remainder being present as cyclic AMP, inosine, hypoxanthine and adenosine. When superfused, the 14C output consisted mainly of adenosine, inosine and hypoxanthine, with some 7 per cent of 5′‐nucleotides and 4 per cent of cyclic AMP.

(3) Electrical pulses and the addition of 50 mm‐KCl each increased the efflux of 14C from superfused [14C]adenosine‐loaded beds. The superfusates issuing after excitation contained the same 14C‐labelled compounds as issued before, with a small increase in the proportional yield of adenosine. The additional output of 14C following electrical pulses was diminished by about 50 per cent by 0.5 μm‐tetrodotoxin while that following KCl was not affected; it was however prevented when the superfusing fluids were free of Ca2+.
DISTRIBUTION OF SERINE HYDROXYMETHYLTRANSFERASE AND GLYCINE TRANSAMINASE IN SEVERAL AREAS OF THE CENTRAL NERVOUS SYSTEM OF THE RAT
Authors: Daly E. C. , Aprison M. H.
Published: October 2006

—The regional distributions of serine hydroxymethyltransferase (SHMT) and glycine transaminase (GT) have been determined in five areas of the CNS of the rat. The SHMT activity per mg protein varied in these areas in the following order: medulia‐pons and spinal cord > cerebellum > midbrain > telencephalon. The GT activity per mg protein was essentially the same in the four brain areas, whereas, in the spinal cord it was lower. The activity of GT did not correlate with the glycine content (r=−0.45. P > 0.05). However, SHMT activity per mg protein was correlated with the glycine content in four regions (the telencephalon, midbrain, medulla‐pons and spinal cord; r= 0.997, P < 0.05). When the activity of SHMT was expressed per relative number of mitochondria, the enzyme levels were correlated with the glycine content in all five areas (r= 0.952, P < 0.05). The distribution of SHMT was determined in the primary subcellular fractions of the CNS. The SHMT activity in these areas of the CNS appeared to be located predominately in paniculate structures, while only 1 to 4 per cent was found in the soluble fraction. The crude nuclear (P1) and the crude mitochondrial (P2) fractions contained 90–97 per cent of the activity. Subfractionation of P2 pellets obtained from the telencephalon, medulla‐pons and spinal cord indicated the SHMT activity was localized in both ‘free’ and occluded mitochondria.
CHARACTERIZATION OF THE FRACTION OBTAINED FROM THE CNS OF JIMPY MICE BY A PROCEDURE FOR MYELIN ISOLATION
Authors: Matthieu Jean‐Marie , Quarles R. H. , Webster H. de F. , Hogan E. L. , Brady R. O.
Published: October 2006

Abstract— A subcellular fraction (called the 0·85‐fraction) was isolated from the brains of Jimpy mice by a procedure for obtaining myelin of high purity from immature normal brains. The yield of this fraction obtained from 17‐day‐old Jimpy mice was only 5 per cent of that from age matched controls. In the electron microscope, the O·85‐fractions obtained from 9‐ and 17‐day‐old control mice showed many multilayered whorls of myelin, whereas the corresponding fraction from the Jimpy mice was free of multilayered structures which could be recognized as myelin. Basic proteins, proteolipid protein and galactocerebrosides could not be detected in the 0·85‐fraction from Jimpy mice although they were major components of the 0·85‐fractions from both 9‐ and 17‐day‐old control mice. The specific activity of 2′,3′‐cyclic nucleotide 3′‐ phosphohydrolase in the Jimpy 0·85‐fraction was only 15 per cent of the value for controls. These results can be explained either by the 0·85‐fraction from Jimpy brain being a very abnormal ‘myelin’ or by its being primarily non‐myelin contaminants. Little or none of the major glycoprotein found in normal myelin fractions was found in the 0·85‐fraction from Jimpy brains. This finding is strong evidence indicating that the glycoprotein is closely associated with normal myelin in situ.
THE SUBSYNAPTOSOMAL LOCALIZATION OF HISTAMINE HISTIDINE DECARBOXYLASE AND HISTAMINE METHYLTRANSFERASE IN RAT HYPOTHALAMUS1
Authors: Snyder S. H. , Brown Birghitta , Kuhar M. J.
Published: October 2006

Abstract— We have examined the subcellular localization of histamine, histamine methyltransferase (EC 2.1.1.8) (HMT) and histidine decarboxylase (EC 4.1.1.22) in rat hypothalamus after osmotic lysis of synaptosome‐containing primary particulate fractions. When crude mitochondrial fractions are subjected to osmotic lysis, histamine is retained within particulate structures, while HMT is released into the supernatant fluid. The majority of histidine decarboxylase activity is also recovered in the supernatant fluid, although more histidine decarboxylase than HMT is retained in particulate fractions. After sucrose gradient fractionation of osmotically lysed crude mitochondrial or microsomal pellets, histamine is also retained in particulate structures, with the greatest amount occurring in a fraction enriched in synaptic vesicles. In these sucrose gradients histidine decarboxylase activity shows a greater particulate localization than does HMT activity.
RADIOMETRIC ASSAY OF TOTAL TRYPTOPHAN HYDROXYLATION BY INTACT CULTURED PINEAL GLANDS
Authors: Bensinger R. E. , Klein D. C. , Weller Joan L. , Lovenberg W.
Published: October 2006

Abstract— A new method is described for the analysis of total tryptophan hydroxylation by intact tissue in culture. This method differs from classical measurements of tryptophan hydroxylase because it allows the detection of changes in tryptophan hydroxylation due to alterations in tryptophan transport, cofactor regeneration and protein synthesis. The rat pineal gland was studied. It was found to hydroxylate tryptophan linearly for a 48‐h period. A direct proportional relationship between the concentration of tryptophan in the culture medium and the amount of tryptophan hydroxylated persists between 0.05 and 0.5 mm. As the medium concn of tryptophan is increased above 0.5 mm the amount of tryptophan hydroxylated decreases. Tryptophan hydroxylation is substantially inhibited by 1 mm p‐chlorophenylalanine and 0.03 mm cycloheximide. No difference in the total amount of tryptophan hydroxylated was detected between male and female rat pineal glands, between chronically denervated and normal rat pineal glands, or between control glands and glands treated with 0.1‐0.001 mm norepinephrine, 0.01 mm isoproterenol, or 0.01 mm mescaline.
CHANGES IN THE DEVELOPMENT OF CENTRAL NOR ADRENALINE NEURONES FOLLOWING NEONATAL ADMINISTRATION OF 6‐HYDROXYDOPAMINE1
Authors: Jonsson G. , Pycock Ch. , Fuxe K. , Sachs Charlotte
Published: October 2006

Abstract— The effects of the neurotoxic compound 6‐hydroxydopamine on central noradrenaline (NA) neurones have been investigated in the adult rat after systemic administration of the drug at birth. This treatment produced a permanent and selective reduction in endogenous noradrenaline, [3H]noradrenaline uptake in vitro and the number of histochemically demonstrable noradrenaline nerve terminals in the forebrain, certainly related to neuroneal degeneration. The fluorescence morphology of the noradrenaline perikarya in the locus coeruleus was not notably affected. In the pons‐medulla region, the 6‐hydroxydopamine treatment led to an almost two‐fold increase in endogenous noradrenaline with a similar increase in [3H]noradrenaline uptake and formation of 3H‐catecholamines from [3H]tyrosine. Fluorescence histochemistry revealed an increased number of noradrenaline nerve terminals which in addition showed an increased fluorescence intensity. Subcellular distribution studies of endogenous noradrenaline in pons—medulla disclosed the highest relative noradrenaline increase in the microsomal fraction after 6‐hydroxydopamine at birth. Sucrose gradient centrifugations disclosed that the pons‐medulla synaptosomes from 6‐OH‐DA treated rats sedimented at a higher sucrose concentration than those from untreated controls. It is concluded that treatment of neonate rats with 6‐hydroxydopamine produces a selective degeneration of noradrenaline nerve terminals in the forebrain, especially in the cerebral cortex, whereas in the pons‐medulla this treatment leads to an increased intraneuronal noradrenaline concentration due to accumulation of noradrenaline in collateral systems not affected by 6‐hydroxydopamine and probably also to an increased outgrowth of noradrenaline nerve terminals.
DISTRIBUTION OF GAMMA‐AMINOBUTYRIC ACID (GABA) IN THE RAT HYPOTHALAMUS: FUNCTIONAL CORRELATES OF GABA WITH ACTIVITIES OF APPETITE CONTROLLING MECHANISMS
Authors: Kimura H. , Kuriyama K.
Published: October 2006

—In the hypothalamus, the highest GABA content (approx. 26 nmol/mm3) was constantly observed in the lateral hypothalamic area (LHA). In other parts of the hypothalamus uneven distribution of GABA was also observed, but areas showing high concentration of GABA did not coincide with the locations of various hypothalamic nuclei. In the LHA, which is known to contain a feeding centre, the anterior part (6.4 and 6.0 mm anterior (A 6.4 and A 6.0) respectively to the vertical zero plane of de Groot) showed a remarkably high content of GABA. The GABA content in the LHA at A 6.4 was decreased during the initial phase of insulin hypoglycemia and, in contrast, showed a significant increase following hyperglycemia induced by alloxan administration. In the ventromedial nucleus (VMH) of the hypothalamus, which is known to contain a satiety centre, the GABA content was increased during the initial phase of insulin hypoglycemia.

The results suggest that both certain parts of the LHA and VMH contain or receive GABA‐inhibitory neurons and that these neurons may play important physiological roles in controlling functional states of the feeding and satiety centres in the hypothalamus.
INHIBITION OF THE TRANSPORT OF 5‐HYDROXYINDOLEACETIC ACID FROM BRAIN BY ETHANOL1
Authors: Tabakoff B. , Ritzmann R. F. , Boggan W. O.
Published: October 2006

—The injection of ethanol in mice produced a transient rise in 5‐hydroxyindoleacetic acid (5‐HIAA) levels in brain. However, no concomitant changes in serotonin (5‐HT) levels were noted. In an attempt to explain the biochemical mechanism by which ethanol produced this effect, uptake of tryptophan by brain, serotonin turnover in brain, and transport of 5‐HIAA from brain were investigated. No changes in tryptophan levels or uptake into brain of ethanol‐treated mice were noted. Ethanol 3 g/kg was found to decrease serotonin turnover. Ethanol was also demonstrated to inhibit the removal of 5‐HIAA from the central nervous system, and was found to be an inhibitor of 5‐HIAA uptake by isolated choroid plexus. The inhibition of biogenic acid transport was noted even at sub‐hypnotic levels of ethanol.
INSULIN AND THE WAY THE BRAIN HANDLES GLUCOSE1
Authors: Daniel P. M. , Love E. R. , Pratt O. E.
Published: October 2006

—In living rats the concentration of insulin in the circulating blood was raised and independently of this the glucose concentration in the blood plasma was varied from hyperglycaemic to hypoglycaemic levels. Hyperglycaemia increased the influx of glucose into the brain and it also, for a limited period, increased the glucose gain by the brain. Insulin, on the other hand, did not affect influx but significantly increased the gain of glucose by the brain. It is suggested that although both hyperglycaemia and insulin can increase glucose gain by the brain they do so in entirely different ways.
MASS FRAGMENTOGRAPHIC DETERMINATION OF SOME ACIDIC AND ALCOHOLIC METABOLITES OF BIOGENIC AMINES IN THE RAT BRAIN
Authors: Karoum F. , Gillin J. C. , Wyatt R. J.
Published: October 2006

—A mass fragmentographic procedure is described for the simultaneous quantification of a number of deaminated metabolites derived from tyramine, octopamine, dopamine, and norepinephrine. With this method, several of the metabolites were measured in normal rat brain. The results support the central nervous system origin of tyramine, octopamine and their metabolites. The concentration of the dopamine metabolite, homovanillic acid, in the rat brain was found to be about 15% higher than that of dihydroxyphenylacetic acid. As for the metabolites of norepinephrine, vanilmandelic acid concentration was found to be about 5% that of 3‐methoxy‐4‐hydroxyphenylglycol. The possible role of vanilmandelic acid in the CNS metabolism of norephrine is discussed.
THE INCORPORATION OF RADIOACTIVE AMINO ACIDS INTO BRAIN SUBCELLULAR PROTEINS DURING TRAINING
Authors: Hershkowitz M. , Wilson J. E. , Glassman E.
Published: October 2006

—Total proteins, free amino acids, tritiated water and subcellular proteins of mouse brain were examined for changes in radioactivity during operant conditioning after subcutaneous administration of labelled amino acids. The conditioning was based on appetitive learning, using sweetened milk as a reward.

During training and incorporation for 20‐30 min, both [3H]leucine and [1‐14C]leucine underwent a significant increase in catabolism, resulting in a decreased radioactivity in the free amino acids. [2‐2H]Methionine underwent a rapid loss of isotope, so that 90% of the radioactivity was in the form of tritiated water at the end of training, and this phenomenon masked any possible effect of training. The brain uptake of [35S]methionine increased during the training, resulting in an increased radioactivity in the proteins. Uptake of [3H]lysine increased slightly during training only after 1 h incorporation and not after 20 or 30 min, as judged from a time course of radioactivity in the free amino acids. Incorporation into nuclear proteins increased selectively during 20 min, and into nuclear and cytosol proteins after 60 min incorporations. It is concluded that changes in the observed rate of incorporation of a precursor into brain subcellular proteins under the influence of behaviour might be the result of changes in precursor catabolism or uptake, or both, and that each amino acid behaves in a different way. Even the same amino acid gives different results depending on the isotope and its position in the amino acid.