bluuebunny/crossref_metadata_2025 huggingface dataset:
AXONAL TRANSPORT IN NIGRO‐NEOSTRIATAL NEURONS DURING MORPHINE TOLERANCE DEVELOPMENT AND ABSTINENCE IN RATS1
Authors: IWAMOTO E. T. , CRAVES F. B. , LOH H. H. , MEYERHOFF J. L. , WAY E. L.
Published: October 2006

Abstract—

Axonal transport of [3H]protein in the nigro‐neostriatal pathway in rats was examined during acute and chronic morphine administration and during morphine abstinence. Two days after a microinjection of [3H]lysine into the left substantia nigra zona compacta, more than 95% of the radioactivity present in the rat forebrain was protein‐bound. Examination of frozen frontal brain sections revealed that 80–90% of the labelled protein of the injected side was located in brain areas traversed by the nigro‐neostriatal pathway. As a positive control, intranigrally administered colchicine reduced the amount of [3H]protein transported after 5 days to the nucleus caudatus‐putamen (neostriatum) to approx 18‐26% of control. In animals rendered morphine‐dependent by subcutaneous implantation of tablets containing 75 mg of morphine base, 27–86% more radioactivity accumulated in the neostriatum at 3, 4 and 5 days after [3H]lysine injection. In contrast, 23–48% less radioactivity was recovered in the neostriatal areas of animals withdrawing from morphine 24 h after [3H]lysine. Gel electrophoresis of soluble and particulate [3H]protein fractions from neostriatal tissues indicated that the gel patterns of radioactivity were not altered by chronic morphine administration. Neither morphine administration nor morphine abstinence altered the rate or amount of [3H]lysine incorporation into protein of the substantia nigra. These data demonstrate that chronic morphine administration was accompanied by a generalized increase in the amount of labelled protein transported to the neostriatum but the procedure was not sufficiently sensitive to detect a minor qualitative alteration of any particular protein(s). Furthermore, these data suggest that either the capacity or the rate of nigro‐neostriatal protein transport may be increased during chronic morphine administration in the rat.
LOCALIZATION OF GABAERGIC, CHOLINERGIC AND AMINERGIC STRUCTURES IN THE MESOLIMBIC SYSTEM
Authors: Fonnum F. , Walaas I. , Iversen E.
Published: October 2006

Abstract— The localization of cholinergic, GABAergic and aminergic structures in the ‘mesolimbic’ system has been discussed from studies on the topographical distribution of choline acetyltransferase, glutamate decarboxylase and aromatic amino acid decarboxylase in normal rat brain and in brains hemitransected at the level of globus pallidus. The structures analysed included nucleus accumbens, olfactory tubercle, septum, medial forebrain bundle, striatum, substantia nigra, ventral tegmental area and nucleus interpeduncularis.

Choline acetyltranferase was highly concentrated in the nucleus interpeduncularis, but it did also exhibit considerable activity in the nucleus accumbens, the olfactory tubercle and the striatum. The activities did not change after hemitransection. Aromatic amino acid decarboxylase was highly concentrated in the ventral tegmental area, but high activities were also found in the striatum, the nucleus accumbens, the olfactory tubercle and the pars compacta of the substantia nigra. The activity decreased in all areas rostral to the hemitransection. Glutamate decarboxylase was highly concentrated in the dopamine innervated regions, moreso in the limbic structures than in the striatum. Much higher activity was found in the substantia nigra than in the ventral tegmental area. After hemitransection the activity in the substantia nigra was decreased whereas in the ventral tegmental area it was unchanged. Our results thus suggest that dopaminergic cells in the ventral tegmental area do not receive GABAergic fibres from the terminal regions of the ascending dopaminergic fibres. In addition, we found a very high concentration of glutamate decarboxylase in a region traversed by the rostral medial forebrain bundle. Here the activity was mainly confined to the paniculate fraction, probably the synaptosomes. This fraction also displayed a very active high affinity uptake of y‐aminobutyric acid.
IDENTIFICATION AND DISTRIBUTION OF SOME MONOAMINES IN TISSUES OF THE SUNFLOWER STAR, PYCNOPODIA HELIANTHOIDES (ECHINODERMATA)
Authors: Juorio A. V. , Robertson H. A.
Published: October 2006

Abstract— The distribution of some monoamines in the tissues of an echinoderm, the sunflower starfish, Pycnopodia helianthoides, has been investigated in order to ascertain whether monoamine levels are similar to those found in other Deuterostomia. Dopamine, noradrenaline and octopamine were present in the arm nerves at concentrations of 5954 ng/g, 2133 ng/g and 260 ng/g respectively. The octopamine/ noradrenaline ratio for the arm nerve was 0.12 and thus similar to the typical mammalian (deuteros‐tome) ratio rather than the higher invertebrate (protostome) ratio. Trace amounts of p‐tyramine, β‐phenylethylamine were also present. 5‐Hydroxytryptamine was not detected but tryptamine was present in high concentrations (1251 ng/g).
SOLUBILIZATION AND CHARACTERIZATION OF THE RAT BRAIN CHOLESTEROL ESTER HYDROLASE LOCALIZED IN THE MYELIN SHEATH1
Authors: Igarashi M. , Suzuki K.
Published: October 2006

Abstract— The cholesterol ester hydrolase of rat brain, localized almost exclusively in the myelin sheath, has been solubilized from the acidic high‐molecular‐weight protein fraction of purified myelin. Solubilization required both high ionic strength and an amphoteric detergent, Miranol H2M. Solubilized preparations with apparent purification factors of 300–500 fold over the starting homogenate still contained approx 25% lipid but were retarded on the Sephadex G‐200 column. The enzyme was reversibly precipitated when the concentration of either Miranol H2M or KCI was lowered below certain critical levels. The soluble enzyme was characterized for the pH optimum, linearity against incubation time and enzyme protein, and apparent Km. Activity was dependent on the presence of exogenously added lipid. Phosphatidylserine at optimum concentrations stimulated the hydrolytic activity 25‐Fold. Effects of other lipids, bile salts, cations, heating and potential inhibitors were examined. β‐Naphthyl oleate was a competitive inhibitor but both β‐naphthyl acetate and cholesteryl butyrate were non‐competitive inhibitors. These results suggested a heterogenous nature of the rat myelin cholesterol ester hydrolase, possibly with different specificities with respect to the chain length of the acyl group of substrates.
THE EFFECTS OF INJECTIONS OF d,l‐5‐HYDROXY‐TRYPTOPHAN ON THE EFFLUX OF ENDOGENOUS SEROTONIN AND 5‐HYDROXYINDOLEACETIC ACID FROM A SYNAPTOSOMAL FRACTION1
Authors: Penn P. E. , McBride W. J.
Published: October 2006

Abstract— The effects of i.p. injections of SO mg/kg d,l‐5‐hydroxytryptophan (5‐HTP) and saline alone on the in uitro release of endogenous serotonin (5‐HT) and 5‐hydroxyindoleacetic acid (5‐HIAA) were studied using preparations of axon terminals (P2 isolated from the telencephalon of rats. The level of 5‐HT was 2‐fold greater and the level of 5‐HIAA was 5‐fold greater in the P2 fraction isolated from rats given the d,l‐5‐HTP injection than from rats given saline injections. At 37°C the in vitro efflux of 5‐HT and 5‐HIAA from the P2 fractions of animals injected with 5‐HTP 30min before killing was approx 3 times higher than the saline control group. The amount of 5‐HT and 5‐HIAA released at 37°C was 3–5 times higher than the amount released at 0°C for both the 5‐HTP and saline injected rats. Increasing the concentration of potassium ions in the media to 55 mm significantly increased the release of 5‐HT but not 5‐HIAA in both groups of animals. The amount of 5‐HT released by 55mm‐K+ was about 2‐fold higher from the P2 fraction isolated from rats given 5‐HTP injections with respect to those given saline injections. The potassium stimulated release of 5‐HT was calcium dependent. The data thus indicate that injection of 50 mg/kg d,l‐5‐HTP in rats can cause an increase in the level of 5‐HT and 5‐HIAA in a crude synaptosomal fraction and that as a result of this increase, there is a temperature dependent increased release of 5‐HT and 5‐HIAA under normal resting membrane conditions. There is also an increased release of 5‐HT as a result of membrane depolarizing conditions induced by elevated potassium levels which is calcium dependent.
RAT BRAIN STEM TRYPTOPHAN HYDROXYLASE: MECHANISM OF ACTIVATION BY CALCIUM
Authors: Hamon M. , Bourgoin S. , Artaud F. , Héry F.
Published: October 2006

Abstract— The activity of soluble tryptophan hydroxylase from rat brain stem was increased in presence of mm concentrations of calcium. Similarly to that observed by treating the enzyme with sodium dodecyl sulphate or trypsin, this activation resulted mainly from an increased affinity of tryptophan hydroxylase for both its substrate, tryptophan, and the cofactor 2‐amino‐4‐hydroxy‐6‐methyl‐5,6,7,8‐tetrahydropteridine (6‐MPH4). In addition, the optimal pH for the enzymic activity was shifted from 7.6 to 7.9 following activation by calcium, sodium dodecyl sulphate or trypsin.

Under the assay conditions used for measuring tryptophan hydroxylase activity, calcium also stimulated a neutral proteinase. This latter enzyme could be eliminated from the solution of tryptophan hydroxylase by filtration through Sephadex G 200. The resulting partially purified tryptophan hydroxylase could be activated by calcium only when the neutral proteinase was included in the assay mixture. In support of this conclusion, the effect of calcium on tryptophan hydroxylase was very small in the new born rat when the activity of the neutral proteinase was low. In addition, the activating effect of Ca2+ could be antagonized not only by a chelating agent like EGTA but also (partially) by specific inhibitors of proteinases such as benzethonium and PMSF.

These results strongly suggest that the activation of tryptophan hydroxylase by calcium is the consequence of a partial proteolysis of the enzyme by the calcium‐dependent neutral proteinase. Therefore, the physiological significance of this irreversible effect is doubtful.
THE SUBCELLULAR DISTRIBUTION OF PARTICLE‐BOUND NEGATIVE CHARGES IN RAT BRAIN
Authors: Bittiger H. , Heid J.
Published: October 2006

Abstract— Ferritin cationized with Girard's reagent T [(CH3)3NCH2CONHNH2] was used as a marker for negative electric charges on subcellular components of rat brain. Pre‐ and postsynaptic membranes did not bind cationic ferritin, either on their outer or their inner surface. Vesicular membranes, however, were heavily labelled with cationic ferritin. Post‐ and presynaptic densities appeared to carry a large number of negative charges. Cationic ferritin was also bound within the synaptic cleft. The density varied, however, from synapse to synapse: in general, binding within the cleft was significantly reduced when the synaptosomes were pretreated with 1 M‐NaCl. Cationic ferritin was observed in high density on the outer surface of myelin sheaths and even between the lamellae at the intraperiod lines. Neuro‐tubules and neurofilaments bound cationic ferritin in significant amounts. The results are discussed in relation to the mechanism of neurotransmission and to the binding and transport of drugs.
METHYLHISTAMINE: EVIDENCE FOR SELECTIVE DEAMINATION BY MAO B IN THE RAT BRAIN IN VIVO
Authors: Waldmeier P. C. , Feldtrauer J.‐J. , Maǐtre L.
Published: October 2006

Abstract— A new method has been developed for the separation of histamine and its metabolites after intracisternal injection of [3H]histamine into the rat brain, involving solvent extraction and subsequent thin‐layer chromatography.

The effect of graded doses of the MAO inhibitors deprenil and pargyline, which at relatively low doses inhibit preferentially the B form (phenethylamine deaminating) of the enzyme, and clorgyline, which mainly inhibits the A form (serotonin, noradrenaline and dopamine deaminating) on the brain levels of intracisternally injected [3H]histamine and its labelled metabolites was studied and compared to MAO A and B activity as determined with the substrates serotonin and phenethylamine, respectively. In addition, the time‐course of the effects of a single dose of pargyline (50mg/kg subcutaneously) was investigated. No [3H]imidazoleacetic acid could be detected in any of the control or treated animals. [3H]Histamine accounted for 9–12% of the total extracted radioactivity and this was not altered significantly by pretreatment with any of the MAO inhibitors up to high doses, at which both MAO A and B activities were completely inhibited.

In the controls, 40–43% of the total extracted radioactivity was [3H]methylhistamine and 28–30% was [3H]methylimidazoleacetic acid. Deprenil and pargyline caused [3H]methylhistamine levels to increase in a dose‐dependent manner up to about 150% of control levels and those of [3H]methylimida‐zoleacetic acid to decrease concomitantly to about 10% of control levels. Clorgyline in doses up to 10 mg/kg subcutaneously (s.c.) had no effect on the levels of these two metabolites. The dose‐response curves of the effects of deprenil and pargyline on [3H]methylimidazoleacetic acid levels were congruent with those of the MAOI effects on MAO B activity and not with those on MAO A activity.

Pargyline (50 mg/kg s.c.) had a long lasting effect on the accumulation of [3H]methylhistamine and [3H]methylimidazoleacetic acid. Recovery occurred within 21 days, and the half‐lives observed were 5.3 and 5.6 days, respectively. This compares well to the half‐life for the recovery of MAO B activity reported earlier after the same dose of pargyline (5.5 days).

These results suggest that methylhistamine is metabolized selectively by MAO B in rat brain. Moreover, the fact that clorgyline, at doses where phenethylamine deamination is already considerably inhibited, did not affect the deamination of methylhistamine, suggests that the latter is an even more selective substrate for MAO B than phenethylamine itself.

Therefore, small doses of deprenil (0.3–3 mg/kg s.c.) or pargyline (1–3 mg/kg) can be used to influence histamine catabolism without interfering with catecholamine or serotonin deamination.
NON‐HISTONE CHROMOSOMAL PROTEINS IN MOUSE BRAIN AT DIFFERENT STAGES OF DEVELOPMENT AND IN A TRANSPLANTABLE MOUSE TERATOMA
Authors: Choi D. D. , Friedber E. C. , VandenBerg S. R. , Herman M. M.
Published: October 2006

Abstract— Non‐histone chromosomal proteins (NHCP) from mouse brain at different stages of development and from adult liver and kidney of strain related mice were analyzed by SDS‐polyacrylamide gel electrophoresis and were compared with the mouse teratoma, OTT‐6050. The fetal, neonatal and adult brains were qualitatively similar in their NHCP profiles but had quantitative differences. The NHCP composition of the adult brain was clearly distinct from that of the liver and kidney and was dissimilar from that of the teratoma.
THE DISTRIBUTION OF NEUROPHYSINS AND POSTERIOR PITUITARY HORMONES IN THE PORCINE NEUROHYPOPHYSEAL SYSTEM
Authors: Dax E. M. , Johnston C. I.
Published: October 2006

Specific, homologous porcine neurophysin I and II radioimmunoassays were established together with specific oxytocin and vasopressin radioimmunoassays. The levels of each of these proteins and peptides were measured in acid extracts of individual paraventricular nuclei, supraoptic nuclei, neurohypophyseal stalks and posterior pituitary lobes of 12 pigs in order to quantitate the neurophysin‐hormone relationships in the porcine neurohypophyseal system. Neurophysin III was found to be immunologically identical to neurophysin I. Neurophysin measurements by radioimmunoassay were quantitatively validated by scanning densitometry of polyacrylamide gels stained with 0.5% amido schwarz.

In the hypothalamic nuclei vasopressin was in 3–4 M excess of oxytocin but in the neurohypophyseal stalk and posterior pituitary lobe the hormones were equimolar suggesting that the rate of formation of vasopressin differs from that of oxytocin. Neurophysin I immunoreactivity was present in a 3:1 molar ratio with neurophysin II throughout the porcine neurohypophyseal system. In posterior pituitary lobes total neurophysins were equimolar to total hormone concentrations. The specific activity (pmol/mg extracted protein) of oxytocin increased 1800 times, vasopressin 560 times and neurophysins about 360 times from the paraventricular nucleus to the posterior pituitary lobe. In the hypothalamic nuclei relationships between immunoreactive neurophysin I and vasopressin, and between neurophysin II and oxytocin were highly significant. In the posterior pituitary lobe each immunoreactive neurophysin level correlated with both hormone levels. Quantification of densitometric scans of stained polyacrylamide gels from neurophypophyseal extracts and immunoreactivity patterns of neurophysins in eluates of sliced, duplicate gels indicated that neurophysin III decreased distally within the neurohypophyseal tract while neurophysin I increased. The results demonstrated that vasopressin was associated with porcine neurophysin I. However, oxytocin may be associated with both immunoreactive neurophysin I and neurophysin II in the porcine neurohypophyseal system if a 1:1 molar ratio of neurophysin to hormone is to be maintained. Neurophysin III contributed to the stoichiometry of this relationship.
BIOSYNTHESIS OF S‐ADENOSYL‐L‐METHIONINE IN THE RAT PINEAL GLAND
Authors: Guchhait Ras B. , Grau James E.
Published: October 2006

This investigation provides direct evidence that rat pineal gland contains ATP:L‐methionine S‐adenosyltransferase. The specific activity of the enzyme is about 25 times greater than that of hydroxyindole‐O‐methyltransferase, the unique marker enzyme in this tissue. The major product of the reaction catalyzed by ATP:L‐methionine S‐adenosyltransferase has been identified as S‐adenosyl‐methionine which can function as a methyl group donor for the formation of melatonin. The specific activity of pineal ATP:L‐methionine S‐adenosyltransferase is at least eight times greater than that of brain, and one‐half that of the liver enzyme.
EVIDENCE FOR STRICTLY Na+‐DEPENDENT ACCUMULATION OF SERINE AND THREONINE IN BRAIN CORTICAL SYNAPTOSOMES FROM NEWBORN RATS
Authors: Peterson N. A. , Raghupathy E.
Published: October 2006

Evidence is presented in this paper to show that synaptosomal particles derived from brains of immature rats possess two separate, high‐affinity transport systems for the hydroxyamino acids, serine and threonine. One of these is strictly Na+‐dependent and the other Na+‐nondependent. The Km terms of both of these systems have values in the range of 20 μM. Na+‐dependent uptakes of serine and threonine do not take place in synaptosomal particles isolated from of adult animals.
THE ONTOGENY OF DOPAMINE‐DEPENDENT INCREASE OF ADENOSINE 3′,5′‐CYCLIC MONOPHOSPHATE IN THE CHICK RETINA
Authors: De Mello F. G.
Published: October 2006

The adenosine 3′,5′‐cyclic monophosphate level of chick embryonic retina changes during the course of development. In retinas from 6‐ to 15‐day‐old embryos the cAMP level is approximately 7 pmol/mg protein. A sharp 3‐fold increase is observed between the 16th and 18th embronic day and remains constant thereafter. A dopamine‐dependent increase in cAMP of the chick retina is already present in 7‐day‐old embryos, and by the 8th embryonic day maximal response is attained. Glutamate promotes a 2‐fold stimulation. Carbachol, γ‐aminobutyric acid and glycine do not cause any significant change in the level of cAMP of the embryonic tissue.

Guanosine 3′,5′‐cyclic monophosphate also accumulates during development. Its concentration is approx 0.5 pmol/mg protein from the 8th to the 14th embryonic day, then increases gradually until the 19th day of development when the level observed is approx 14 pmol/mg protein.
DNA‐DEPENDENT RNA POLYMERASES FROM RAT BRAIN, AND RNA SYNTHESIS IN GLIAL AND NEURONAL CELL‐ENRICHED FRACTIONS, AFTER PROTEIN RESTRICTION
Authors: Kubaat.G. Birgitta , Morean Marianne , Decken Alexandra von der
Published: October 2006

DNA‐dependent RNA polymerases were extracted from rat brain and separated by column chromatography on DEAE Sephadex into enzyme I and II. After 6 days of dietary protein restriction the α‐amanitin sensitive RNA polymerase II showed a decrease in activity per total brain wet weight, and per mg brain DNA. RNA polymerase I was unchanged under these conditions. The acid‐soluble pool of nucleotides was also unaffected. Separation of brain tissue into glial‐ and neuronal‐enriched cells revealed dietary effects on RNA synthesis in glial but not in neuronal elements.

Brain wet weight and DNA content remained unaltered after 6 days of protein restriction: but body weight was reduced by 1.3 g day. Control rats increased in weight by 7.7 g/day.
BIOCHEMICAL CHARACTERIZATION OF THE NEURON: RIBONUCLEIC ACID COMPOSITION OF THE NEURONAL CELL BODIES
Authors: Okazaki Hiroko , Abe Sachiko , Satake Mei
Published: October 2006

Base composition of the two major RNA species, 18 S and 28 S, from the neuron were determined. Bulk isolation of the neuronal cell bodies, acrylamide gel electrophoresis of RNA and the microelectrophoresis of the hydrolysate of RNA species were carried out successively for this purpose. It is revealed that 28 S RNA has a base composition which resembles those reported for the cerebral cortex and other tissues. The base composition of the 18 S RNA from the neuron, however, differs from cerebral cortex and other tissue base compositions in that the neuronal 18 S RNA contains a higher percentage of C and a lower percentage of G compared with other tissues.
ENHANCED CEREBRAL PROTEIN SYNTHESIS IN DEVELOPING HYPOTHYROID RATS: EVIDENCE FOR DELAYED MATURATION
Authors: Gonzales Linda W. , Geel Stanley E.
Published: October 2006

(1) Neonatal hypothyroidism resulted in a 40% increase in the incorporation of [14C]leucine into protein by cerebral cortical slices from 25‐day‐old rats. The uptake of the [14C]‐labelled amino acid into the acid‐soluble free amino acid pool was similar in hypothyroid and control groups which excluded the possibility that transport differences contributed to the observed differences in incorporation. (2) The conversion of [14C]leucine in the free amino acid pool to other metabolites was substantially greater in the hypothyroid state compared to euthyroid controls. (3) The correction of the incorporation data for radioactivity associated with [14C]leucine in the precursor pool, provided an estimate of cerebral protein synthetic rate which was markedly higher in thyroid hormone‐deficient‐rats compared to litter mate controls. (4) The administration of L‐thyroxine to hypothyroid animals for two successive days essentially returned the accelerated metabolism of the precursor pool leucine to normal but failed to ameliorate the increased incorporation into protein. (5) Incubations conducted in the presence of high exogenous leucine levels, to eliminate possible differences in intracellular free amino acid pool size, provided additional evidence for an increased rate of cerebral protein synthesis in 25‐day‐old hypothyroid rats compared to controls. (6) The results are compatible with a retardation in the normal developmental decline in the rate of cerebral protein synthesis associated with hypothyroidism.
IDENTIFICATION AND QUANTIFICATION OF 3‐METHOXY ‐4‐HYDROXYPHENYLLACTIC ACID (VLA) IN CEREBROSPINAL FLUID AND 3‐METHOXY‐4‐HYDROXY PHENYLPYRUVIC ACID (VPA) IN THE URINE OF PARKINSONIAN PATIENTS TREATED WITH L‐DOPA
Authors: Muskiet F. A. J. , Jeuring H. J. , Teelken A. W. , Wolthers B. G. , Lakke J. P. W. F.
Published: October 2006

The identification and quantification of 3‐methoxy‐4‐hydroxyphenyllactic acid in cerebrospinal fluid, and 3‐methoxy‐4‐hydroxyphenylpyruvic acid in the urine of Parkinsonian patients on medication with l‐3,4‐dihydroxyphenylalanine with or without a peripheral decarboxylase inhibitor are described. Data are also given for other catecholamine‐ and catecholamine precursor metabolites in urine and cerebrospinal fluid. Analyses were performed by means of gas chromatography with flame ionization or mass spectrometric detection. We have concluded that following the administration of l‐3.4‐dihydroxyphenylalanine + peripheral decarboxylase inhibitor. 3‐methoxy‐4‐hydroxyphenyllactic acid must be considered as a quantitatively important metabolite of L‐3.4‐dihydroxyphenylalanine in cerebrospinal fluid. In addition, some comment is given on the presence of 3‐methoxy‐4‐hydroxy‐phenylpyruvic acid in the urine of these patients.
PRODUCTS OF BIOGENIC AMINE METABOLISM IN THE LOBSTER: SULFATE CONJUGATES
Authors: Kennedy Mary B.
Published: October 2006

Abstract—

Octopamine, dopamine and serotonin, the three biogenic amines found in the lobster nervous system, are each converted by lobster tissues into two principal classes of products, A and B metabolites. In this paper, evidence is presented that the B metabolites are sulfate conjugates of the amines and their A metabolites. Two double‐labelled conjugates were formed from each of the three amines during incubations of lobster nerves with tritiated amine and 35SO4. When the two octopamine conjugates were hydrolyzed by mild acid, one of the conjugates was converted to a mixture of 35SO4 and [3H]‐octopamine, and the other to a mixture of 35SO4, [3H]octopamine, and [3H]metabolite A. [3H]Metabolite A was also converted to octopamine by acid hydrolysis. The results indicated that one of the double‐labelled conjugates was octopamine‐sulfate, and the other metabolite‐A‐sulfate. An enzyme fraction prepared from nerve homogenates catalyzed the synthesis of double‐labelled sulfate conjugates from the tritiated amines and [35S]3′‐phosphoadenosine‐5′‐phospho‐sulfate. Double‐labelled conjugates formed in this way contained 1 mol of sulfate per mol of amine. Indirect evidence suggested that the sulfate was in ester linkage with the ring hydroxyls of the amines.

Neither monoamine oxidase, nor catechol‐O‐methyl transferase is found in lobster tissues; therefore, in these animals, sulfation may be a major means of inactivation of the biogenic amines following their release from nerve endings.
MEASUREMENT OF ACETYLCHOLINE TURNOVER WITH GLUCOSE USED AS PRECURSOR: EVIDENCE FOR COMPARTMENTATION OF GLUCOSE METABOLISM IN BRAIN
Authors: Gibson Gary E. , Blass John P. , Jenden Donald J.
Published: October 2006

Abstract—

The turnover of acetylcholine in whole mouse brain in vivo has been determined using [U‐14C]glucose as a precursor of the acetyl moiety. The standard requirements for the measurement of turnover were met: the injection did not change the concentrations of precursor or product, the amount of radioactivity in the brain was proportional to the amount injected, and the relationship between the specific activity of glucose and that of acetylcholine was typical of a precursor and a product. The value for acetylcholine turnover was 64 pmol/min per mg protein, approx 6.4 nmol/min per g brain. Treatment with amobarbital (0.16 mmol/kg) decreased the incorporation of glucose into acetylcholine by 73 × 7%, and treatment with atropine increased it by 18 × 6%. These values agree with those using choline as a precursor, supporting the validity of the values for turnover obtained with either labelled precursor.

The specific activity of acetylcholine was higher than that of pyruvate at all times in mouse brain in vivo and in rat brain slices in vitro. These observations demonstrate compartmentation of glucose metabolism with respect to acetylcholine synthesis in the brain. They agree with observations by others of compartmentation of acetyl metabolism. They provide an explanation for the close linkage which has been observed between carbohydrate catabolism and acetylcholine synthesis in the CNS.
STUDIES ON NICOTINIC ACETYLCHOLINE RECEPTORS IN MAMMALIAN BRAIN. CHARACTERIZATION OF A MICROSOMAL SUBFRACTION ENRICHED IN RECEPTOR FUNCTION FOR DIFFERENT NEUROTRANSMITTERS
Authors: de Blas Angel , Mahler Henry R.
Published: October 2006

Abstract— A subfraction, derived from the microsomal fraction of rat cerebral cortex, with a buoyant density of 1.112 g μ ml−1 appears to be enriched in receptor sites for a number of potential neurotrans‐mitters. These include the cholinergic (nicotinic and muscarinic) and ß‐adrenergic receptors. This microsomal subfraction (P3B2) has been isolated on a preparative scale by two sequential isopycnic sedimentations in discontinuous sucrose gradients.

We have studied the morphology, enzymatic markers and protein composition of this fraction and have compared them with the properties of other subcellular fractions from the same source. Synaptic plasma membranes resembled P3B2 by exhibiting the same high extent of enrichment in receptors. However, the synaptic membranes appear to contain more mitochondrial and presynaptic (axonal and cell surface) membranes than does P3B2, and the postsynaptic membranes in the two fractions appear morphologically distinct since P3B2 does not contain the characteristic postsynaptic densities. Thus these membranes may be derived from Gray's type II synapses.
ACTIVE UPTAKE OF [3H]5‐HT BY SYNAPTIC VESICLES FROM RAT BRAIN
Authors: Halaris Angelos E. , DeMet Edward M.
Published: October 2006

Abstract—

The question of whether synaptic vesicles accumulate [3H]5‐HT by an active process was investigated in a mixed population of vesiclcs from whole rat brain. The temperature dependence and the effect of metabolic inhibitors were studied in synaptosomal suspensions and vesicular fractions. Arrhenius plots for synaptosomes differed from those for vesicles as did the temperature coefficients for these two fractions. For synaptosomes the Q10 was 7 and for vesicles 1.6. However, if ATP was added to the incubation, the temperature dependence of vesicular amine accumulation became manifest; the Arrhenius plot resembled that of synaptosomes and the Q10 was greater than 20 indicating strong temperature dependence. In the presence of ATP, vesicular uptake was stimulated approx 8‐fold. Ouabain, dinitrophenol and NEM inhibited synaptosomal uptake but failed to affect [3H]5‐HT accumulation by vesicles in the absence of ATP. When ATP was added, vesicular uptake was also blocked by NEM but was unaffected by either ouabain or DNP. Total observed uptake consisted of two components, one ATP‐dependent and one nonsaturable and ATP‐independent. The active process had a Km= 1.25 × 10−7 M and could be completely blocked by either 10−3 M or 10−7 M‐reserpine. Active vesicular [3H]5‐HT uptake was magnesium dependent and was inhibited by sodium and potassium. Cation effects on uptake were specific and could not be accounted for by either changes in osmotic pressure or ionic strength. It was concluded that synaptic vesicles from whole rat brain accumulate [3H]5‐HT by an active process.
THE FLUX OF RADIOACTIVE LABEL THROUGH COMPONENTS OF THE SEROTONERGIC SYSTEM FOLLOWING THE INJECTION OF [3H]TRYPTOPHAN: PRODUCT–PRECURSOR ANOMALIES PROVIDING EVIDENCE THAT SEROTONIN EXISTS IN MULTIPLE POOLS1
Authors: Lane J. D. , Aprison M. H.
Published: October 2006

Abstract— Rats were given an intravenous injection of 100 μCi of l–[3H]tryptophan and were killed between 5 and 180 min post–injection. Brains were dissected into seven areas, and specific activities were determined for major components (tryptophan, 5–hydroxytryptophan. serotonin and 5–hydroxy–indoleacetic acid) and detectable minor components (tryptamine, 5–methoxytryptamine. 5–hydroxyindo–lepyruvic acid, and 5–hydroxytryptophol) of serotonergic metabolism. The minor components represented small amounts of the total radioactivity with respect to the four major components. Anomalies in the product–precursor relationships for 5–hydroxytryptophan and serotonin, as well as for serotonin and 5–hydroxyindoleactic acid, suggest intraneuronal compartmentation of serotonin.
CUTANEOUS SHOCK PRODUCES CORRELATED SHIFTS IN SLOW POTENTIAL AMPLITUDE AND CYCLIC 3′,5′‐ADENOSINE MONOPHOSPHATE LEVEL IN THE PARIETAL CORTEX OF THE CONSCIOUS RAT1
Authors: Skinner James E. , Reed Jane C. , Welch K. M. A. , Nell Janet H.
Published: October 2006

Abstract— Fourteen animals each received 4 cutaneous shocks with an interval of 3–5 min between them. During a fifth trial 3–5 min later, eleven subjects received a fifth shock and then 3–30 s afterwards, as cerebral slow potentials developed in response to the stimulus, samples of parietal cortex were rapidly frozen and extracted by a cryoplate. Three baseline subjects received no shock at the time of the fifth trial and had their parietal tissue samples taken without the presence of slow potentials. A correlation coefficient of r=−0.77 (P < 0.01) was observed between the slow potential amplitude on the surface of the parietal cortex at the time of the sampling and the analyzed level of cyclic AMP in the underlying tissue. Five of the shocked animals whose samples were taken before the slow potentials increased significantly showed a tissue level of 11.1 ± 3.0 pmol cyclic AMP/mg protein. This level was significantly higher (P < 0.01) than that of the baseline animals (3.1 ± 2.0 pmol cyclic AMP/mg protein). The other six shocked animals who had developed large slow potentials manifested a cyclic AMP level that was not different from the baseline group. It is concluded that a reoccurring cutaneous shock results in the immediate increase in the level of cyclic AMP in the parietal cortex and that within 30 s this level decreases in proportion to the amplitude of the slow potential that develops in the same region.
CYCLIC AMP‐DEPENDENT PROTEIN KINASE ACTIVITY AND SYNAPTOSOMAL PROTEIN PHOSPHORYLATION IN THE BRAINS OF AGED RATS
Authors: Schmidt Michael J. , Truex Lewis L. , Conway Richard G. , Routtenberg Aryeh
Published: October 2006

Abstract—

The activity of soluble protein kinase and phosphorylation of endogenous synaptosomal proteins were studied in vitro, in the hippocampus and cerebral cortex of rats 3, 12, or 24 months of age. No between‐age differences in the activity of cyclic AMP‐dependent or independent protein kinase were detected in either brain region. The degree of stimulation by cyclic AMP and the apparent Ka, for cyclic AMP were similar at all stages. Cyclic AMP stimulated the phosphorylation of synaptosomal proteins from the cerebral cortex, hippocampus, caudate nucleus, and cerebellum of rats at all ages. There were no significant differences across age in the extent of phosphorylation of any membrane proteins in any brain region. The number and staining density of synaptosornal proteins separated by polyacrylamide gel electrophoresis were also similar at all ages. These studies indicate that the cyclic AMP‐dependent phosphorylation system in the rat brain does not change during advanced aging.
A BIOCHEMICAL‐BEHAVIORAL MODEL FOR STUDYING SEROTONERGIC SUPERSENSITIVITY IN BRAIN
Authors: Fleisher L. N. , Simon J. R. , Aprison M. H.
Published: October 2006

Chronic treatment with p‐chlorophenylalanine methylester (PCPA) resulted in enhanced sensitivity to D,L‐5‐hydroxytryptophan (5‐HTP) induced inhibition of response rates in rats working on a Variable Interval 1 min schedule of milk reinforcement. Marked depletions of 5‐hydroxytryptamine (5‐HT) were found in the cerebral cortex, hippocampus, striatum, diencephalon, mesencephalon, and pons‐medulla oblongata. Much smaller dopamine depletions were seen in some areas, particularly the hippocampus and pons‐medulla oblongata. Analysis of the binding of [3H]5‐HT to crude membrane fractions from the cerebral cortex of PCPA‐treated animals indicated a significant decrease in the apparent dissociation constant (KdAPP) for 5‐HT, but no change in the maximum binding capacity. The increased behavioral sensitivity to 5–HTP does not seem to be due to increased conversion of 5‐HTP to 5‐HT, increased uptake of 5‐HTP, or release of 5‐HT by p‐chlorophenylethylamine. However, the possibility that p‐chlorophenylalanine or the metabolite p‐chlorophenylacetic acid increased the binding of 5‐HT, thus decreasing KdAPP, cannot be ruled out. Some parallels between a recently proposed model of human depression and the observations of the present investigation are discussed.
INCORPORATION OF AXONALLY TRANSPORTED SUBSTANCES INTO MYELIN LIPIDS
Authors: Haley James E. , Ledeen Robert W.
Published: October 2006

Abstract— The possibility that axonally transported lipids and/or proteins might undergo transaxonal migration and become incorporated into surrounding myelin lamellae was studied by isolating myelin from optic tracts of myelinating rabbits at various times following intraocular injection of [3‐14C]‐serine and [2‐3H]glycerol. Myelin isolated by a procedure employing ethylene glycol‐bis(β‐aminoethyl ether)‐.N,N'‐tetraacetic acid had relatively constant specific radioactivity with respect to both isotopes over a 21 day period. Myelin lipids showed a gradual increase in 14C specific radioactivity, attributed to reutilization of [14C]serine from the axon by a compartment of the oligodendrocyte. Free serine is postulated to arise in the axon from catabolism of axonally transported proteins (and possibly lipids) and to migrate transaxonally into the neighboring oligodendroglia. This reutilization mechanism resulted in synthesis of myelin cerebrosides, sphingomyelin, ethanolamine phosphoglycerides and possibly sulfatides, but not gangliosides or serine phosphoglycerides. The data for choline‐ and inositol‐phosphoglycerides are inconclusive. [3H]Glycerol‐labeled myelin lipids decreased slowly in 3H specific radioactivity with time, indicating either that [2‐3H]glycerol does not participate in the reutilization pathway or that the label is lost in the process. Evidence is presented that 3H‐ and 14C‐labeled lipids are true myelin constituents. Lipids from the myelin, axolemma‐ and axon‐enriched fractions tended to converge in specific radioactivity over the 21 days, especially the former two fractions. These results together with isotope ratio changes point to an equilibration process whereby lipids are able to transfer. (or exchange) between the 3 compartments. Protein radioactivity in isolated myelin was suggested to arise from residual axon/axolemma contamination, and no evidence was found for transaxonal migration of protein into myelin. The 2 mechanisms elucidated here are believed to account for a quantitatively small portion of myelin lipid and are considered to represent a form of axon‐glia interaction.
METABOLITE LEVELS IN BRAIN FOLLOWING EXPERIMENTAL SEIZURES: THE EFFECTS OF MAXIMAL ELECTROSHOCK AND PHENYTOIN IN CEREBELLAR LAYERS
Authors: McCandless D. W. , Feussner G. K. , Lust W. D. , Passonneau J. V.
Published: October 2006

Abstract— The effects of maximal electroshock (MES) and phenytoin on metabolites and cyclic nucleotides in layers of frozen‐dried cerebellum have been investigated. The four layers (molecular, Purkinje‐cell rich, granular and white matter) had remarkably homogeneous distributions of P‐creatine, ATP, glucose, glycogen, lactate, GABA and the cyclic nucleotides. MES caused dramatic decreases in P‐creatine, ATP, and glucose at 10 s after treatment, followed by a decrease in glycogen at 30 s. Lactate levels were elevated, and GABA was unchanged. Cyclic AMP concentrations were increased at 10s and cyclic GMP at 30 s. Phenytoin modified most of the MES induced changes in all the layers, although white matter was less affected by MES and/or phenytoin. Lactate concentrations were increased by MES and these effects were not altered when phenytoin was administered. The most dramatic effects of phenytoin were on the changes in cyclic nucleotides. Cyclic AMP concentrations were elevated after MES but the values returned to normal more rapidly when phenytoin was present. The drug almost obliterated the MES induced changes in cyclic GMP. The possible relationship of cyclic nucleotide concentrations and the modulation of seizure activity is discussed.
A DIRECT METHOD FOR DETERMINING DOPAMINE SYNTHESIS AND OUTPUT OF DOPAMINE METABOLITES FROM BRAIN IN AWAKE ANIMALS
Authors: Maas J. W. , Hattox S. E. , Martin D. M. , Landis D. H.
Published: October 2006

Abstract— A direct method for measuring the rate of dopamine (DA) synthesis and the DA metabolites by the brain of awake monkeys (Macaca arctoides) is described. The method utilizes a coupling of a measure of cerebral blood flow with the mass spectrometrically determined difference in the concentrations of the metabolite under study in plasma obtained from arterial and internal jugular bulb blood. For homovanillic acid (HVA) a consistent and highly significant veno‐arterial (V‐A) difference of 2.2 ± 0.4 ng/ml of plasma (P < 0.0005) was found. When this V‐A difference was coupled with a measure of cerebral blood flow it was determined that, in the awake monkey, the average output of HVA by brain was 113.4 ± 19.1ng/100g brain min−1. There were large individual variations, however, between animals (range = 38‐194 ng/100g brain min−1). In contrast to HVA, no consistent V‐A difference for dihydroxyphenylacetic acid (DOPAC) was found; i.e. the concentrations of DOPAC in plasma obtained from arterial and internal jugular bulb venous blood were essentially identical. These data indicate that, in contrast to the rat, in this non‐human primate HVA is the major metabolic product of brain DA. Since HVA is the major metabolite of DA, production of HVA under steady state conditions gives a measure of DA synthesis by whole brain; i.e. the rate of DA synthesis by whole brain in the awake monkey is 113.4 ± 19.1ng/100g brain min−1. It is suggested that this technique may be of value in both basic and applied types of studies.
INHIBITION OF BRAIN GLUTAMATE DECARBOXYLASE BY 2‐KETO‐4‐PENTENOIC ACID, A METABOLITE OF ALLYLGLYCINE1
Authors: Reingold Diane F. , Orlowski Marian
Published: October 2006

Abstract— 2‐Keto‐4‐pentenoic acid, a potent inhibitor of brain glutamate decarboxylase (Orlowskiet al., 1977) was prepared by oxidative deamination of l‐allylglycine with snake venom l‐amino acid oxidase. In the presence of glutamate the keto acid is a competitive inhibitor of the enzyme with respect to glutamate; its Ki is 2.4 ± 10−6m. After preincubation of brain glutamate decarboxylase with 2‐keto‐4‐pentenoic acid in the absence of glutamate, a slow and incomplete reactivation is obtained by prolonged dialysis, Sephadex gel‐filtration, and dilution, suggesting the formation of a slowly dissociating enzyme‐inhibitor complex and partial inactivation of the enzyme.

In vivo inhibition of brain glutamate decarboxylase after administration of allylglycine is maximal after 2‐8 h with activity returning to normal after 16 h. The inhibition of the enzyme after administration of d‐allylglycine was greatest in the cerebellum and the medulla‐pons area, the sites of the highest activity of d‐amino acid oxidase. These results are interpreted as strongly supporting the postulate that allylglycine‐induced inhibition of brain glutamate decarboxylase is due to the in vivo formation of 2‐keto‐4‐pentenoic acid.
EFFECT OF PENTOBARBITAL ON MITOCHONDRIAL SYNTHESIS IN CULTURED GLIAL CELLS
Authors: Roth‐Schechter B. F. , Winterith M. , Tholey G. , Dierich A. , Mandel P.
Published: October 2006

Abstract— Primary cultures of glial cells prepared from brains of newborn rats were grown for 1 week and then exposed to 5 × 10−4m‐pentobarbital (PB) for 4 weeks. Compared with glial cells grown in drug‐free medium throughout, exposure to PB significantly increased hexokinase activity, primarily in its mitochondrial form. Furthermore, cellular protein and RNA concentrations were significantly higher in barbiturate‐cultivated than in control cells. Pulse labelling with [3H]thymidine after 4 weeks of PB exposure resulted in a significant increase (332%) in 3H incorporation into mitochondrial DNA while 3H incorporation into nuclear DNA was reduced by 58%. In addition, there was a time dependent increase in the size and number of mitochondria as determined in electron micrographs. These results are interpreted to reflect an increased mitochondrial metabolism in glial cells after chronic exposure to the barbiturate and may constitute a compensatory mechanism to the depressant action of this drug.
CORTICOTROPHIN INCREASES CEREBRAL POLYAMINE CONTENT
Authors: Tintner Ron , Dunn Adrian J. , Iuvone P. Michael , Shukla Jayesh B. , Rennert Owen M.
Published: October 2006

Abstract— To determine whether changes in cerebral polyamines might mediate previously reported ACTH‐induced changes in brain biochemistry and behavior, the cerebral content of polyamines was examined following ACTH treatment. Male CD‐1 mice were injected daily for 3 days with long‐acting (zinc phosphate) preparations of ACTH1–24 (1 μg/g) or ACTH4–10 (0.33 μg/g) and killed 24 h after the last injection. Putrescine, spermidine and spermine contents were determined by high pressure liquid chromatography. Putrescine content was significantly elevated in all brain regions by ACTH1–24 (approx 50%), and in the telencephalon by ACTH4–10 At the dose tested ACTH4–10 was less effective than ACTH1–24. Telencephalic spermidine was also elevated (10%)by ACTH1–24, but spermine content was not altered in any brain region. One injection of the long‐acting ACTH1–24 preparation elevated telencephalic putrescine (49%) 24 h post‐injection. ACTH1–24 (1 μg/g) in saline produced a peak elevation of all three telencephalic polyamines 6 h post‐injection, while in the liver only putrescine was significantly elevated and reached a peak at 10h. Neither plasma polyamine nor ornithine concentrations were significantly altered by any of the treatments. Corticosterone, in both single and multiple injection regimens, failed to alter telencephalic polyamine content. Adrenalectomy, however, prevented the ACTH1–24‐induced increase in telencephalic polyamines. It is concluded that ACTH acts directly in the brain to increase cerebral polyamine concentrations. The possibility that adrenal hormones exert permissive effects on this action is discussed.
MUSCARINIC CHOLINERGIC STIMULATION INCREASES CYCLIC GMP LEVELS IN RAT HIPPOCAMPUS1
Authors: Black Asa C. , Sandquist Dean , West James R. , Wamsley James K. , Williams Terence H.
Published: October 2006

Abstract— Muscarinic cholinergic agonists increase cyclic GMP levels in a number of neural tissues. Since the rat hippocampus receives a cholinergic innervation from the septum, we decided to test whether cyclic GMP levels of the rat hippocampus are increased by bethanechol, a muscarinic cholinergic agonist. Incubation of rat hippocampi with varying concentrations of bethanechol showed that the increase in cyclic GMP levels is concentration‐dependent, 500 pwbethanechol producing a maximum increase of 490% over control values. The bethanechol‐evoked increases were blocked by the muscarinic antagonist atropine, and were calcium‐dependent. It is concluded that at least some of the cells projecting to the rat hippocampus form muscarinic cholinergic synapses which act via a cyclic GMP‐dependent mechanism.
DEVELOPMENTAL AND OTHER ASPECTS OF [35S]CYSTEINE TRANSPORT BY RAT BRAIN SYNAPTOSOMES
Authors: Hwang Shing‐Mei , Segal Stanton
Published: October 2006

Abstract— Cysteine uptake by rat brain synaptosomes occurs by active transport. The uptake by synaptosomes isolated from newborn brain is slower and the concentration gradient achieved is lower than that observed in adult tissue. Synaptosomal fractions from both adult and newborn rat brains accumulate cysteine by two saturable systems. The calculated parameters show that the maximum rates of cysteine uptake in adult synaptosomes are approximately twice that observed in newborn synaptosomes for both the high and low affinity systems. The uptake by the high affinity system is sodium dependent and is inhibited by glycine and dibasic amino acids. Uptake by synaptosomes from 14‐day‐old animals is close to that observed in adult tissue. The uptake of cysteine differs greatly from that of cystine since the oxidized form, cystine, is taken up more slowly by systems with low affinities which are sodium independent, do not interact with dibasic amino acids and are independent of age.