bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation and Properties of an Immunosorbent Column Specific for the Myelin Basic Protein
Authors: Reidl Linda S. , Campagnoni Celia W. , Campagnoni Anthony T.
Published: October 2006

Abstract: An immunosorbent column specific for the myelin basic protein (BP) was prepared by coupling purified anti‐BP antibodies to cyanogen bromide (BrCN)‐activated Sepharose 4B. The BP‐immunosorbent column bound BP between pH 4.5 and pH 6.8. In its working range the column bound approximately 400‐475 μg of BP at pH 6.8 and 250 μg at pH 4.5 with recoveries of 72‐77%. The BP‐immunosorbent column could effectively separate BP from simple mixtures of BP and proteins of similar size and charge and from acid extracts of bovine brain. The results indicate that the BP‐immunosorbent column can be used to isolate BP from a mixture of proteins and may be adapted for use in the small‐scale purification of the myelin basic proteins involving a minimum number of steps.
γ‐Aminobutyric Acid Concentration in Cerebrospinal Fluid in Schizophrenia
Authors: McCarthy B. W , Gomes U. R , Neethling A. C , Shanley B. C , Taljaard J. J. F , Potgieter L , Roux J. T
Published: October 2006

Abstract: γ‐Aminobutyric acid (GABA) concentration was determined in cerebrospinal fluid (CSF) of acute and chronic schizophrenic patients, in persons with psycho‐organic or personality disorders, and in nonpsychiatric controls. The mean CSF GABA level in the chronic schizophrenic patients was found to be significantly higher than in any of the other groups. No other statistically significant differences were found. Statistical analysis revealed that the elevated CSF GABA concentration in the chronic schizophrenic patients was unlikely to be caused by medication. These results are interpreted as evidence for possible primary or secondary GABAergic overactivity in the brain in chronic schizophrenia.
A Comparison of the Polypeptide Pattern Between a Brain Primary Culture and Fractions of Bulk‐Isolated Glial Cells
Authors: Hansson Elisabeth , Rönnbäck Lars , Sellström Åke
Published: October 2006

Abstract: This paper reports on the electrophoretic protein/polypeptide pattern of a rat brain primary culture. For comparison, the polypeptide pattern of neuronal and glial enriched fractions from adult rat brain and cerebral hemispheres from newborn and adult rat have been analysed. Water‐soluble and SDS‐extractable polypeptide fractions appeared and/or increased in amount in the cultures until confluency. The polypeptide pattern of the cultures most resembled that of the glial cell fractions, showing some of this fraction's specificity. Removal of fetal calf serum and addition of 0.1 mM dibutyryl cyclic adenosine monophosphate (dB‐cAMP) produced few changes in the electrophoretic pattern. The study thus provides evidence in favour of the astroglial nature of the brain primary culture. It also shows that the cells undergo some maturation in the culture.
Effect of Undernutrition on Tryptophan and Tyrosine Hydroxylases in the Developing Rat Brain
Authors: Kalyanasundaram S , Ramanamurthy P. S. V
Published: October 2006

Abstract: Rats born to well‐fed mothers (20% protein diet ad libitum), protein‐restricted mothers (7.5% protein diet ad libitum) or pair‐fed with protein‐restricted mothers were killed on days 0, 7, 14, 21, 28 and 35 and activities of the two enzymes of neurotransmitter synthesis, tryptophan‐5‐hydroxylase (EC 1.14.16.4) and tyrosine hydroxylase (EC 1.14.16.2) were assayed. Enzyme activities in normal animals were low at birth and progressively increased to reach adult levels by day 15. Protein‐restricted and pair‐fed animals also showed a similar pattern. However, significantly higher activities were observed from day 15 onwards in both experimental groups.
Inhibition of Aminopeptidase and Acetylcholinesterase by Puromycin and Puromycin Analogs
Authors: Hersh Louis B
Published: October 2006

Abstract: Puromycin analogs in which the O‐methyl‐L‐tyrosine moiety was substituted by a number of amino acids were examined as inhibitors of the puromycin‐sensitive rat brain aminopeptidase and bovine erythrocyte acetyl‐cholinesterase. In the case of the aminopeptidase, the structure and stereochemistry of the amino acid substituent were important factors in determining inhibitor effectiveness. In the case of the acetylcholinesterase reaction, the aminonucleoside of puromycin was nearly as effective an inhibitor as puromycin itself, with little effect dependent on the nature or stereochemistry of the amino acid.
The Na+,K+ ‐ATPase: A Plausible Trigger for Voltage‐Independent Release of Cytoplasmic Neurotransmitters
Authors: O'Fallon James V. , Brosemer Ronald W. , Harding Joseph W.
Published: October 2006

Abstract: A comparison was made between the releasability of eight neurotransmitters from eight regions of mouse brain in response to either 60 μM‐K+ or 20 μM‐ouabain, a specific inhibitor of the Na+, K+‐ATPase. With few exceptions, all transmitters were released by either or both agents from each brain region examined. Potassium was superior in releasing the biogenic amines and acetylcholine, while the putative amino acid transmitters were generally releasable by both agents. Measurements of tissue depolarization using [3H]‐tetraphenylphosphonium uptake indicated that 60 μM‐K+ is capable of depolarizing brain tissue above the threshold necessary for initiating an action potential, but 20μM‐ouabain is not. The pattern of release by ouabain coupled with its failure to depolarize brain tissue at 20μM suggests that inhibition of the Na+,K+‐ATPase is capable of releasing cytoplasmic neurotransmitters in a voltage‐independent manner.
Acetylation of Choline and Homocholine by Membrane‐Bound Choline‐O‐Acetyltransferase in Mouse Forebrain Nerve Endings
Authors: Benishin C. G. , Carroll P. T.
Published: October 2006

Abstract: The choline analog homocholine is not acetylated in vitro by choline‐O‐acetyltransferase (ChAT, EC 2.3.1.6), which is solubilized by 100 mM‐sodium phosphate buffer washes of a crude vesicular fraction of mouse forebrain. However, both homocholine and choline are acetylated by a form of ChAT which is nonionically associated with a subcellular fraction of mouse forebrain containing membrane‐associated organelles and occluded acetylcho‐line (P4). Acetylation of homocholine by membrane‐associated ChAT is saturable. 4‐(1‐Naphthylvinyl)pyridine (NVP) inhibits the acetylation of both choline (60%) and homocholine (40%) by membrane‐associated ChAT but reduces the acetylation of choline alone by soluble ChAT (76%). Choline and homocholine serve as competitive alternative substrates for the same membrane‐associated ChAT, whereas homocholine acts only as a competitive inhibitor of choline acetylation by soluble ChAT. Acetylhomocholine competitively inhibits the acetylation of choline by both soluble and membrane‐associated ChAT more dramatically than does the natural end product, acetylcholine.
High‐Affinity [3H]Choline Accumulation in Cultured Human Skin Fibroblasts
Authors: Riker Donald Kay , Roth Robert H. , Breakefield Xandra O.
Published: October 2006

Abstract: [3H]Choline can be transported across cell membranes by high‐affinity (KT 5 μM) and low‐affinity (KT≫ 5 μM) systems. High‐affinity choline accumulation (HACA) has been demonstrated in synaptosomes made from cholinergic brain regions such as the hippocampus and caudate‐putamen. In cell culture. HACA has been demonstrated in glia and avian telencephalon, dissociated spinal cord, and muscle fibroblasts. We examined [3H]choline accumulation in a single normal human fibroblast line cultured from skin biopsy. [3H]Choline accumulation was temperature‐dependent and linear with incubation time up to 6 min at 0.125 μM‐choline. The apparent KT for [3H]choline was 5 μM which is similar to that observed in avian fibroblasts. Isoosmotic replacement of Na+ with either Li+ (144 MM) or sucrose (288 mM) severely reduced [3H]choline accumulation (by 70–90%). Pre‐incubation with ouabain (100 μM), sodium orthovanadate (100 μM), or 2,4‐dinitrophenol (100 μM), or replacement of Ca2+ by Mg2+ had little or no effect on subsequent [3H]choline accumulation. [3H]Choline accumulation was inhibited by hemicholinium‐3 (HC‐3); after pre‐incubation in HC‐3 at 37°C for 10 min, the IC50 (at 0.125 μM‐chohne) was 5.6 μM. The HC‐3 sensitivity, Na+ dependence, and low KT suggest that human skin fibroblasts have a high‐affinity transport system for choline.
Characterization of Two [3H]Glutamate Binding Sites in Rat Hippocampal Membranes
Authors: Baudry Michel , Lynch Gary
Published: October 2006

Abstract: The specific binding of l‐[3H]glutamate was investigated in the presence and the absence of sodium ions in freshly prepared membranes from rat hippocampus. Sodium ions were found to have a biphasic effect; low concentrations induced a marked inhibition of the binding (in the range 0.5‐5.0 mM), whereas higher concentrations resulted in a dose‐dependent stimulation of binding (in the range 10‐ 150 mM). These results permit the discrimination of two binding sites in hippocampal membranes. Both Na+‐independent and Na+‐dependent binding sites were saturable, exhibiting dissociation constants at 30°C of 750 nM and 2.4 μM, respectively, with Hill coefficients not significantly different from unity, and maximal number of sites of 6.5 and 75 pmol/mg protein, respectively. [3H]Glutamate binding to both sites reached equilibrium between 5 and 10 min and was reversible. The relative potencies of a wide range of compounds, with known pharmacological activities, to inhibit [3H]glutamate binding were very different for the Na+‐independent and Na+‐ dependent binding and suggested that the former sites were related to postsynaptic glutamate receptors, whereas the latter were related to high‐affinity uptake sites. This conclusion was also supported by the considerable variation in the regional distribution of the Na+‐dependent binding site, which paralleled that of the high‐affinity glutamate uptake; the Na+‐independent binding exhibited less regional variation.
Lipid Composition in Ganglia of Mollusca
Authors: Bolognani L. , Masserini M. , Bodini P. A. , Fantin A. M. Bolognani , Ottaviani E.
Published: October 2006

Abstract: The aim of the present study is to ascertain lipid composition in the ganglia of Mollusca. Nervous ganglia in the periesophageal ring dissected from Helix pomatia, Lymnaea stagnalis, Murex trunculus and Murex brandaris were studied by biochemical and histochemical procedures. Glycosphyngolipids are present mainly as sulpholipid; sialic acid and gangliosides are not present as revealed by Svennerholm's reaction and TLC separation. The phospholipidcholesterol ratios are: 0.47 (Helix), 0.42 (Lyrnnaea), 0.86 (Murex brandaris) and 1.01 (Murex trunculus).
Noncompetitive Amine Uptake Inhibition by the New Antidepressant Pridefine
Authors: DeMet Edward M. , Vosmer Georgetta , Halaris Angelos E.
Published: October 2006

Abstract: Pridefine (AHR‐1118) is a pyrrolidine derivative with clinically established antidepressant efficacy. Previous work from this laboratory indicates that pridefine is a reuptake blocker of catecholamines and serotonin with weak releasing activity. This study characterized the mode of amine uptake inhibition by pridefine as noncompetitive. The uptake experiments were performed utilizing ouabain instead of zero‐degree controls to differentiate between the passive and active components of uptake. Furthermore, the passive component was resolved into diffusion and binding of substrate. Correction was made for the effects of ouabain on binding. Kinetic constants determined from Lineweaver‐Burk plots were: Km= 3 × 10−7 M for NE, Km= 9 × 10−8 M for DA, and Km= 3 × 10−8 M for 5‐HT. Dixon analyses of uptake at various pridefine concentrations indicated noncompetitive inhibition with Ki= 2.5 × 10−6 M for NE uptake, Ki= 2.0 × 10−6 M for DA uptake, and Ki= 1 × 10−5 M for 5‐HT uptake. These constants compare well with IC50 values for the same transmitters: NE, IC50= 2.4 × 10−6 M; DA, IC50= 2.8 × 10−6 M; 5‐HT, IC50= 1.0 × 10−5 M. The in vitro results indicate that pridefine is relatively specific as a catecholamine uptake blocker. It differs from tricyclic antidepressants which are reportedly competitive inhibitors of monoamine uptake. The possible mechanisms by which pridefine acts as a noncompetitive inhibitor are discussed.
Effect of Intravenous Administration of d‐Lysergic Acid Diethylamide on Subsequent Protein Synthesis in a Cell‐Free System Derived from Brain
Authors: Cosgrove James W. , Clark Bruce D. , Brown Ian R.
Published: October 2006

Abstract: An initiating cell‐free protein synthesis system derived from brain was utilized to demonstrate that the intravenous injection of d‐lysergic acid diethylamide (LSD) to rabbits induced a transient inhibition of translation following a brief stimulatory period. Subfractionation of the brain cell‐free system into postribosomal supernatant (PRS) and microsome fractions demonstrated that LSD in vivo induced alterations in both of these fractions. In addition to the overall inhibition of translation in the cell‐free system, differential effects were noted, i.e., greater than average relative decreases in in vitro labeling of certain brain proteins and relative increases in others. The brain proteins of molecular weights 7SK and 95K, which were increased in relative labeling under conditions of LSD‐induced hyperthermia, are similar in molecular weight to two of the major “heat shock” proteins reported in tissue culture systems. Injection of LSD to rabbits at 4°C prevented LSD‐induced hyperthermia but behavioral effects of the drug were still apparent. The overall decrease in cell‐free translation was still observed but the differential labeling effects were not. LSD appeared to influence cell‐free translation in the brain at two dissociable levels: (a) an overall decrease in translation that was observed even in the absence of LSD‐induced hyperthermia and (b) differential labeling effects on particular proteins that were dependent on LSD‐induced hyperthermia.
Uridine Metabolism in the Goldfish Retina During Optic Nerve Regeneration: Cell‐Free Preparations
Authors: Kohsaka Shinichi , Dokas Linda A. , Agranoff Bernard W.
Published: October 2006

Abstract: The activities of uridine kinase (EC 2.7.1.48), uridine monophosphate (UMP) kinase (EC 2.7.1.3.14), and uridine diphosphate (UDP) kinase (EC 2.7.4.6) were measured in retinal high‐speed supernatant fractions following unilateral optic nerve crush in the goldfish. The enzyme activities followed a similar time course, with initial increases 2‐3 days following nerve crush, peak activity at 4 days, and a gradual return to basal levels by day 21. The magnitude of the stimulation on day 4 was about 35% in each case. Activities of two enzymes of intermediary metabolism, pyruvate kinase (EC 2.7.1.40) and lactic dehydrogenase (EC 1.1.1.27), were not altered, indicating that the coordinate increases in nucleoside and nucleotide kinase activities were specific responses to the nerve injury. The increased labeling could not be explained by altered phosphohydrolytic activities. The nature of the enhancement was further studied in UDP kinase, the most active of the kinases examined. Neither low‐molecular‐weight components nor substrate availability could account for the observed increase in UDP kinase in the 4 day post‐crush retinas. The Km, for UDP was unaltered, and a mixing experiment did not support the possibility that stimulatory or inhibitory factors played a role. The enhancement of UDP kinase activity was blocked by injection of actinomycin D following nerve crush. The results suggest that the observed increases in enzymes of uridine metabolism result from their increased formation following nerve crush.
Antagonism of Excitatory Amino Acid‐Induced and Synaptic Excitation of Spinal Neurones by cis‐2,3‐Piperidine Dicarboxylate
Authors: Davies J. , Evans R. H. , Francis A. A. , Jones A. W. , Watkins J. C.
Published: October 2006

Abstract: In tests on neurones in the cat spinal cord in vivo, and frog and immature rat spinal cord in vitro, cis‐2,3‐piperidine dicarboxylate (cis‐2,3‐PDA) produced the following effects: (1) selective antagonism of amino acid‐induced responses, compared with responses to other putative transmitters; (2) effective antagonism of kainate and quisqualate‐induced responses in addition to responses induced by N‐methyl‐D‐aspartate (NMDA) and other excitatory amino acids; (3) partial NMDA‐like agonist action; (4) antagonism of dorsal root‐evoked excitation of Renshaw cells; (5) potentiation of acetylcholine‐ and ventral root‐evoked excitation of Renshaw cells. This unique spectrum of action may be useful for transmitter receptor characterization in the vertebrate central nervous system.
Cleavage of Rabbit Myelin Basic Protein by Pepsin
Authors: Martenson Russell E. , Liithy Vivian , Deibler Gladys E.
Published: October 2006

Rapid cleavage of bovine and guinea pig myelin basic proteins by pepsin at pH 6.0 is limited to the Phe‐Phe bond in the middle of the molecule. In the rabbit protein, however, rapid cleavages occur elsewhere in addition to the Phe87‐Phe88 bond in regions in which there are amino acid substitutions. Rapid cleavage occurs at the Leu151‐Phe152 bond, at which Ile‐151 has been replaced by Leu, the residue that actually contributes the scissile bond. Rapid cleavages occur at the Phe44‐Phe45 and Leu109‐Ser110 bonds, which in the bovine and guinea pig proteins are relatively resistant under the experimental conditions (pH 6.0). The increased susceptibility of these bonds in the rabbit protein appears to be related to the replacement of Gly‐46 by Ser and the change in the sequence immediately NH2‐terminal to Leu‐109, from Leu‐Ser to Thr‐Val. These cleavages of the rabbit protein at the four very susceptible bonds have permitted us to isolate peptides (1‐44), (45‐87), (88‐109), (110‐151), and (152‐168) in high yield. We have also isolated peptides (88‐151), (1‐14), and (15‐44) in low yield; the latter two result from limited cleavage at the relatively resistant Tyr14Leu15 bond. Peptide (88‐109) has been chromatographically resolved into species differing in the degree of methylation of Arg‐105; this resolution is thought to result from differences in hydrogen bonding ability of the guanidinium groups.
Change of Cyclic AMP Level in Synaptosomes from Cerebral Cortex; Increase by Adenosine Derivatives
Authors: Kobayashi Kazuo , Kuroda Yoichiro , Yoshioka Masanori
Published: October 2006

The endogenous level of cyclic AMP in incubated synaptosomes from cerebral cortex of guinea pigs was investigated after the addition of various agents to the incubation medium. It appeared that the synaptosomal suspension already contained exogenous adenosine. Preincubation with theophyl‐line or with adenosine deaminase (ADase) decreased both the exogenous level of adenosine and the intrasynaptosomal level of cyclic AMP. The level of cyclic AMP was reincreased by the addition of adenosine agonists, especially 2‐chloroadenosine. This increase was antagonized by deoxyadenosine and was not inhibited by dipyridamole. These results suggest that the adenosine derivatives in the synaptic cleft regulate the level of cyclic AMP in nerve terminals through adenosine receptor on the presynaptic membrane. ADP, ATP, dopamine, and histamine also stimulate the formation of cyclic AMP in the ADase‐treated synaptosomes.
Brain Slice Protein Degradation and Development
Authors: Dunlop David S. , van Elden Walter , Plucinska Izabela , Lajtha Abel
Published: October 2006

Protein degradation rates were measured in brain slices prepared from rats of various ages. This was done by adding the protein synthesis rate, determined by incorporation of a labeled precursor, and the net protein degradation rate, determined by measuring the changes with time of total free amino acids. These rates are about 30% higher than those previously calculated from data on protein synthesis rates and protein accumulation rates in vico. The protein degradation rates in brain slices diminish with age; i.e., 2‐day cerebellum > 2‐day cerebral hemisphere > 12‐day cerebral hemisphere > young adult cerebral hemisphere. Protein degradation rates in slices from young brain are initially slightly higher than protein synthesis rates, resulting in a small net degradation with time. Unlike slices from adult brain, the protein degradation rates in slices from young brain decline only modestly with time for as much as 100 min of incubation. The characteristics of protein degradation in brain slices from young animals are roughly similar to some of the data calculated for protein degradation in vivi. suggesting that this system may prove useful for studying factors which control or affect brain protein degradation.
[3H]Propyl β‐Carboline‐3‐Carboxylate Binds Specifically to Brain Benzodiazepine Receptors
Authors: Nielsen Mogens , Schou Henning , Braestrup Clam
Published: October 2006

Ethyl β‐carboline‐3‐carboxylate has recently been isolated from human urine and it was proposed that derivatives of this compound might be related to an endogenous ligand for benzodiazepine receptors. In the present study we investigated high‐affinity binding of [3H]propyl β‐carboline‐3‐carboxylate ([3H]PrCC) to rat brain membranes. [3H]PrCC binds specifically and with high affinity (half‐maximal binding at ca. 1 nM) to rat brain membranes. The regional and subcellular distributions of specific [3H]PrCC binding are similar, but not identical, to the distributions of [3H]flunitrazepam or [3H]‐diazepam binding. The total numbers of binding sites labelled by [3H]PrCC and [3H]flunitrazepam in rat cerebellum are closely similar, and both ligands bind to cerebellar membranes in a mutually exclusive way. The pharmacological selectivity of [3H]PrCC and [3H]diazepam binding is almost identical. Binding of [3H]PrCC, like binding of [3H]diazepam, can be increased in vitro by muscimol, GABA and SQ 20.009. Although subtle differences in binding characteristics were observed, these results indicate that [3H]PrCC and benzodiazepines bind to a common recognition site on benzodiazepine receptors.
A Simple Radioenzymatic Method to Measure Picogram Amounts of DOPA in Brain and Biological Fluids
Authors: Argiolas A. , Gessa G. L.
Published: October 2006

A simple radioenzymatic method for the determination of DOPA is described. The method is based on the conversion of DOPA to 3‐O‐[methyl‐3H]DOPA by catechol‐O‐methyltransferase in the presence of S‐adenosyl‐[methyl‐3H]methionine and purification of the labelled product by Sephadex G10 and Dowex 50 W × 4 ion exchange resin. The method has been applied to the assay of endogenous DOPA in different brain areas and to measuring DOPA accumulation after inhibition of aromatic amino acid DOPA decarboxylase.
Distribution of Protein I, a Synapse‐Specific Phosphoprotein, and Adenylate Cyclase in the Rat Spinal Cord
Authors: Ueda Tetsufumi , Stratford Carol A. , Larson James
Published: October 2006

The longitudinal and transverse distributions of the synapse‐specific phosphoprotein Protein I and adenylate cyclase in the rat spinal cord were studied. Protein I was found to be enriched in all cervical and midlumbar (L3‐L5) segments, and sparse in midthoracic and sacral segments. Adenylate cyclase activity was high in all cervical and lumbosacral segments, and low in mid‐thoracic segments. Cross‐sectionally, both Protein I and adenylate cyclase were more enriched in the dorsal half than in the ventral half in the various segments studied. The similar topographical distributions of Protein 1 and adenylate cyclase in the spinal cord support the idea that adenylate cyclase may be intimately associated with Protein I in the nervous system, and could thereby regulate the state of in vivo phosphorylation of Protein I through formation of cyclic AMP.
Studies on Lipase in Rat Brain
Authors: Mizobuchi Masato , Shirai Kohji , Matsuoka Nobuo , Saito Yasushi , Kumagai Akira
Published: October 2006

Lipase activity was measured in homogenates of rat cerebral hemispheres using radioactive glycerol trioleate emulsified with Triton X‐100 as substrate. The labeled oleic acid was separated from the ester with a methanol‐chloroform‐heptane mixture. Under these assay conditions, the activity showed pH optima at about 5.5 and 7.5. The final products of these lipase activities were suggested to be free fatty acid and glycerol.
Regional Distribution of Catalase in the Adult Rat Brain
Authors: Brannan Timothy S. , Maker Howard S. , Raes Ingrid P.
Published: October 2006

Catalase activity was measured in 11 areas of perfused adult rat brain. The hypothalamus and substantia nigra contained the highest activities. The corpus callosum. a white‐matter structure, contained intermediate activity. The caudate‐putamen and frontal cortex contained the lowest activities. Regional catalase bears some relationship to the reported distribution of microperoxisomes, but considerable activity is present in areas with few microperoxisomes. Catalase may function as one of the systems detoxifying H2O2 formed in CNS amine metabolism.
Inhibition by Neurotoxic Phospholipases A2 of Synaptosomal Uptake of γ‐Aminobutyric Acid
Authors: Ng Ronald H. , Howard Bruce D.
Published: October 2006

A comparison has been made of the abilities of several neurotoxic and nontoxic phospholipases A2 from snake venoms to inhibit the intake of γ‐aminobutyric acid into synaptosomes from rat cerebral cortex. The neurotoxic phospholipases A2 inhibited GABA uptake more than the nontoxic enzymes did. However, there was a poor correlation between the measured specific enzyme activity of a phospholipase A2 and its ability to inhibit the uptake of GABA.
Molecular Forms of Acetylcholinesterase in Pineal Cell and Sympathetic Neuronal Cultures
Authors: Rowe Vernon , Fernandez Hugo , Fernandez Hugo , Duell Myron , Parr James , Battie Cynthia
Published: October 2006

Abstract The activities of the various molecular forms of acetylcholinesterase (AChE) were measured in monolayer cultures of neonatal rat pineal cells grown alone and in co‐culture with sympathetic neurons. AChE forms characterized by sedimentation coefficients of 4S, 6.5S, and 10S were found in the neuronal and pineal cultures, as well as in the co‐cultures. The 16S AChE form was found only in the neuronal cultures. Total AChE activity increased with culture age in the co‐cultures, but it decreased in pineal cells cultured alone. The low level of activity present in the neuronal cultures did not change markedly over the 27‐day culture period. These results, which show bidirectional neuron‐pineal cell effects, suggest that AChE molecular forms may be important markers to study the mechanisms underlying neuron‐target cell interaction in the developing sympathetic nervous system.
Dynamic Changes of Serotonin Levels During the First Visual Experience of Binocularly Deprived Kittens
Authors: Kossut Malgorzata , Wójcik Magdalena , Skangiel‐Kramska Jolanta
Published: October 2006

Abstract— Kittens deprived of pattern vision until the 28th day of life received monocular visual experience for 3, 6, 14, and 75 h. Biphasic response of serotonin was found in the visual cortex. Stimulation for 3 h resulted in an increase of serotonin level whereas at 14 h it produced a decrease. The effects are transient, no longer observable after 75 h stimulation. No changes were observed in somatosensory cortex.
Fucose Incorporation and Identification of Fucosylglycoproteins in Synaptosomes
Authors: Branford White C. J. , Dawson J. M.
Published: October 2006

Abstract— A synaptosome‐enriched fraction from sheep cortex was incubated with l‐fucose. The uptake of the sugar into this preparation was dependent on time, temperature, and concentration. A A K mapp of 0.94 mm‐l‐fucose and a V maxapp value of 0.24 nm‐l‐fucose/mg synaptosomal soluble protein/20 min was determined. After incubation for 10 min at 25°C with l‐[3H]fucose, 70% of the radioactive label was found in the soluble fraction. DEAE‐cellulose chromatography resulted in the elution of three fucosylprotein peaks which were then characterised by gel filtration and sodium dodecyl sulfate‐polyacrylamide electrophoresis (SDS‐PAGE). At least eleven 3H protein‐staining bands were identified with M. W. 13,000‐115,000. Control experiments involving the incubation of the hexose with heat‐treated synaptosomes and myelin, mitochondria, and microsomes indicated that the tritiated material associated with the synaptosomal soluble fraction was not due to nonspecific binding or to the presence of contaminating subcellular material. A 3H glycopeptide was identified, and on analysis the carbohydrate moiety was found to be rich in sialic acid, fucose, galactose, mannose, and N‐acetylglucosamine. Mild acid treatment of the glycopeptide released fucose, which implies that this carbohydrate occupies a terminal position in the oligosaccharide chain. From these results it is proposed that synthesis or the modification of soluble fucosylglycoproteins is possible in synaptosomes.
Brain Levels of Neuron‐Specific and Nonneuronal Enolase in Huntington's Disease
Authors: Marangos P. J. , Paul S. M.
Published: October 2006

Abstract— Levels of the cell‐specific brain isoenzymes of enolase were determined in basal ganglia and cerebral cortical tissue of Huntington's disease and age‐ and sex‐matched control brain. Neuron‐specific enolase (NSE) levels are decreased an average of 45% in basal ganglia from patients with Huntington's disease whereas the glial‐specific form of enolase, nonneuronal enolase (NNE), is not significantly altered. In contrast, levels of NSE in cerebral cortical tissue from Huntington's disease patients remains unchanged in comparison with controls whereas NNE levels are significantly increased. NNE and NSE levels appear to be specific biochemical indicators of glial and neuronal cell number and viability. Levels of these cell‐specific isoenzymes may therefore prove useful in quantitating neuropathological changes in various neurological disorders.
Acetylcholine Synthesis and CO2 Production from Variously Labeled Glucose in Rat Brain Slices and Synaptosomes
Authors: Ksiezak Hanna J. , Gibson Gary E.
Published: October 2006

Abstract: The molecular basis of the close linkage between oxidative metabolism and acetylcholine (ACh) synthesis is still unclear. We studied this problem in slices and synaptosomes by measurement of ACh synthesis from [U‐14C]glucose, and 14CO2 production from [3,4‐14C]‐ and [2‐14C]glucose, an index of glucose decarboxylation by the pyruvate dehydrogenase complex (PDH) and the enzymes of the Krebs cycle, respectively. We examined both under conditions that either inhibited (low O2 or antimycin) or stimulated (2,4‐ dinitrophenol [DNP] or 35 mm‐K+) 14CO2 production from [2‐14C]‐ or [3,4‐14C]glucose. Incorporation of [U‐14C]glucose into ACh was reduced under low O2 and by antimycin or DNP (by 51‐93%) and stimulated by 35 mm‐K+ (by 30‐60%). Under all of these conditions, ACh synthesis and the decarboxylation of [3,4‐14C]‐ and [2‐14C]glucose were linearly related (r= 0.741 and 0.579, respectively). The difference in the rate of 14CO2 production from [3,4‐14C]‐ and [2‐14C]glucose was used as a measure of the amount of glucose that was not oxidatively decarboxylated (efflux). We found that efflux was reduced (low 02 and antimycin), unchanged (DNP in slices), or increased (DNP in synaptosomes and K+ stimulation in slices) compared with control values under 100% O2. ACh synthesis and efflux were more closely related (r= 0.860) than ACh synthesis and 14CO2 production from variously labeled glucoses.
Analysis of α‐Bungarotoxin Binding in the Goldfish Central Nervous System
Authors: Oswald Robert E. , Freeman John A.
Published: October 2006

Abstract: We report here the equilibrium, kinetic, and pharmacological analysis of α‐125I‐bungarotoxin (α‐125I‐Bgt) binding to a Triton x‐100‐solubilized goldfish brain synaptosomal fraction. In addition, a refined analysis of equilibrium binding to a particulate synaptosomal fraction is presented. Equilibrium binding from both particulate and soluble fractions revealed an apparent heterogeneity of binding sites. Kinetic analysis of the soluble receptor revealed linear association kinetics and nonlinear dissociation kinetics. The dissociation curve suggested the presence of at least two rate constants. Potential sources of the binding heterogeneity found in both the equilibrium binding and dissociation kinetics experiments are (1) multiple receptor species, (2) multiple ligand species, and (3) different, possibly interconvertible, states of a single receptor type. No evidence for the first two alternatives was found. Support for the third alternative was obtained by observing the effect of cholinergic ligands on α‐125I‐Bgt dissociation. Carbamylcholine and d‐tubocurarine increased the apparent proportion of rapidly dissociating sites, suggesting that the two binding affinities can be interconverted and may arise from a single receptor type. Evidence concerning the identity of the α‐Bgt binding protein as a nicotinic acetylcholine receptor is discussed.
The Effect of Mesencephalic Lesions on Tyramine and Dopamine in the Caudate Nucleus of the Rat
Authors: Juorio A. V. , Jones R. S. G.
Published: October 2006

Abstract: The dopamine (DA)‐containing nerve terminals in the caudate nucleus arise from cell bodies located in the substantia nigra (pars compacta), and it is possible that p‐tyramine‐ and m‐tyramine‐containing neurons may also exist in this nucleus. We have studied the effects of unilateral electrolytic lesions of the pars compacta in rat on levels of DA, p‐tyramine, m‐tyramine, and homovanillic acid in the caudate nucleus after various survival times. At 12 and 24 h following lesioning the ipsilateral level of p‐tyramine was significantly reduced compared with the contralateral side, whereas the concentrations of m‐tyramine, DA, and homovanillic acid were significantly increased. Thus, in the short term, the lesion results in an increase in DA turnover, which is accompanied by an increase in m‐tyramine levels and a decrease in p‐tyramine levels. Similar changes occur following pharmacological treatments (chlorpromazine, d‐amphetamine, l‐DOPA) that increase DA turnover. At survival times of 2, 11, and 25 days, the ipsilateral concentrations of m‐tyramine, DA, and homovanillic acid were reduced along with p‐tyramine. These longer‐term alterations in amine levels are most likely a consequence of degeneration of nigro‐striatal axons. Placement of a lesion 1 mm dorsal to the usual position centering on the pars compacta produced different biochemical changes from those seen after the pars compacta lesion. One day following this lesion the concentration of p‐tyramine was slightly reduced; DA was unaffected, but the concentration of m‐tyramine was profoundly increased, even more so than after the pars compacta lesion. This could indicate the existence of specific m‐tyramine‐containing cell bodies located dorsal to the substantia nigra. The results suggest that p‐ and m‐tyramine in the caudate nucleus originate from neurons in or close to the substantia nigra. The results in the short term following the lesion support the observation that there is an inverse relationship between p‐tyramine concentration and DA turnover in the caudate nucleus.
Effects of Cell Density on Lipids of Human Glioma and Fetal Neural Cells
Authors: Liepkalns V. A. , Icard C. , Yates A. J. , Thompson D. K. , Hart R. W.
Published: October 2006

Abstract: Gangliosides, phospholipids, and cholesterol of human glioma (12‐18) and fetal neural cells (CH) were analyzed at specified cell densities, from sparse to confluent. Total ganglioside sialic acid, phospholipid phosphorus, and cholesterol increased in the glioma cells on a per cell, mg protein, or mg total lipid basis two‐ to threefold as cell density increased 25‐fold. These same three constituents in the fetal cells increased with cell density on a per cell and mg protein basis but not on a per mg total lipid basis. In glioma cells, the di‐ and trisialogangliosides (GD2+ GDlb+ GT1) increased from 1–2% of total ganglioside sialic acid at sparse densities to 7–8% at intermediate (logarithmic phase) densities to 10–13% at confluent densities. The set of simpler gangliosides (GM4+ GM3+ GM2) decreased from 50% of total ganglioside sialic acid at sparse glioma cell densities, to 36% at intermediate and 30% at confluent densities. In the fetal neural cells, the set of gangliosides (GM4+ GM3+ GM2) had about 48% of total ganglioside sialic acid in both sparse and confluent preparations. The fetal cells were twofold higher in GM3 (32.4 ± 2.1%) than the glioma cells (16.8 ± 1.6%), but lower in GMt (9.1 ± 0.9% versus 18.2 ± 1.8%), cell densities notwithstanding. Confluent cell preparations of both cell lines were consistently higher in ethanolamine plasmalogen than sparse cells. We conclude that in these two neural cell lines quantitative changes in ganglioside and phospholipid species occurred correlatively as cell densities increased. Higher glioma cell densities were associated with greater proportions of complex ganglioside species. These changes in cell membrane constituents during growth may result from cell contact and may indicate a role for them in cell growth regulation and/or differentiation.
Characterization of 2′:3′‐Cyclic Nucleotide 3′‐Phosphodiesterase: Limited Proteolytic Digestion, Plant Lectin Affinity Chromatography, and Immunological Identification
Authors: Müller Hans Werner , Clapshaw Patric A. , Seifert Wilfried
Published: October 2006

Abstract: Purified bovine brain 2′:3′‐cyclic nucleotide 3′‐phosphodiesterase (CNPase) migrates as a protein double band in SDS‐polyacrylamide gel electrophoresis. The positions of the two protein bands correspond to approximate molecular weights (MW) of 56,000 and 53,000. Limited protease treatment of isolated CNPase leads to subsequent degradation of the enzyme into smaller polypeptides having MWs of approximately 40,000, 30,000, and 20,000. During proteolytic digestion CNPase remains enzymatically active. Binding studies with several immobilized plant lectins as well as periodic acid‐Schiff reagent (PAS) staining of SDS gels indicate that CNPase is a glycoprotein. An antiserum against purified CNPase, prepared in rabbits, was used to confirm the immunological identity of various CNPase preparations obtained in our laboratory.
Development and Localization of the Thymidine Phosphorylating Systems in Brain
Authors: Spector Reynold
Published: October 2006

Abstract: The development of the thymidine phosphorylating systems was studied in various regions of brain. Brain slices from cerebellum, brain stem, and forebrain of rabbits 2, 7, 14, 30, 90, 500, and 2500 days of age were incubated for various times in artificial CSF containing 3 nM‐[3H]thymidine at 37°C under 95% O2‐5% CO2. When slices from all brain regions of 2‐day‐old rabbits were incubated in [3H]thymidine for 30 min, tissue‐to‐medium ratios of 3H were between 2 and 4 and declined with age, and the percentages of the total 3H in perchloric acid homogenates of brain slices as [3H]DNA were 26–29%, declining to low levels with age. However, at all ages and in all regions studied, 41 ‐88% of the 3H within the slices was phosphorylated. After homogenization and subcellular fractionation of the brain slices incubated in [3H]thymidine for 30 min, the highest percentage of [3H]thymidine phosphates plus [3H]DNA was present in the nuclear (crude and purified) and mitochondrial fractions of all brain regions. The [3H]DNA content in the nuclear and mitochondrial fractions declined with age, but the percentage of [3H]thymidine phosphates did not. Thymidine phosphates were synthesized from thymidine in all brain regions tested throughout the entire life span.
The Regional Distribution of Monoamine Oxidase Activities Towards Different Substrates: Effects in Rat Brain of Chronic Administration of Manganese Chloride and of Ageing
Authors: Leung Thomas K. C. , Lai James C. K. , Lim Louis
Published: October 2006

Abstract: The effects of chronic manganese chloride administration (1 mg MnCl2 4H2O/ml of drinking water) and ageing on the regional distribution of monoamine oxidase (MAO, EC 1.4.3.4) were studied in 2‐month‐ and 24–28‐month‐old rats. In both the control and Mn‐treated rats, the serotonin oxidation (type A) rates decreased in hypothalamus, pons and medulla, striatum, midbrain and cerebral cortex, but not in cerebellum, in ageing. On the other hand the benzylamine oxidation (type B) rates in hypothalamus, striatum and cerebral cortex increased in ageing. In all regions except the cerebellum, there was a uniform decrease in the A/B ratio. This decrease was verified by differential inhibition studies using clorgyline and l‐deprenyl, specific type A and type B inhibitors respectively. The dopamine‐oxidising rates decreased in all regions, except the cerebral cortex and the cerebellum, in ageing control rats. This age‐related decrease was not seen in the striatum and midbrain of manganese‐treated rats. In these rats the other effect was an age‐related increase in the rate of oxidation of all the amines in the cerebellum, not observed in control rats. These selective effects of manganese are only seen when comparing age‐related changes in both groups of animals, since comparison of manganese‐treated rats with age‐matched controls showed a significant difference only in the rate of serotonin oxidation in the cerebellum of 2‐month‐old rats. The relationship of these observations to the effects of ageing and manganese encephalopathy on specific amine systems is discussed.
Estimate of the Molecular Weight of the Sarcolemmal Sodium Channel Using H2O‐D2O Centrifugation
Authors: Barchi R. L. , Murphy L. E.
Published: October 2006

Abstract: The sodium channel saxitoxin binding component from rat sarcolemma was solubilized with NP‐40 and centrifuged on sucrose gradients constructed in either D2O or H2O. When compared with a series of standard proteins the sedimentation behavior of the solubilized channel complex changed from an apparent S20.w of 9.1 in H2O to 6.1 in D2O. From these observations, a true partial specific volume of 0.83 ml/g was calculated for the complex. A Stokes radius of 8.6 nm was estimated from Sepharose 6‐B chromatography in NP‐40. The calculated protein molecular weight of the lipid‐protein‐detergent complex based on these data is 560,000. The complex contains about 56% protein, and the calculated molecular weight of this component is 314,000 if a v for the protein of 0.74 ml/g is assumed.
Fatty Acid Activation and Temperature Perturbation of Rat Brain Microsomal Phospholipase D
Authors: Chalifour Robert , Kanfer Julian N.
Published: October 2006

Abstract: The hydrolytic and transphosphatidylation activities of rat brain microsomal phospholipase D were highly latent in the absence of an appropriate activator. The most suitable surfactants for this activation were oleate and palmitoleate. Besides the bile acids and unsaturated fatty acids, other naturally occurring surfactants, such as lysophospholipids, acidic phospholipids, acyl‐CoA's, and gangliosides, were inactive. Taurodeoxycholate, at optimal concentration, produced a profound inhibition of oleate activation. Phospholipase D activity was detectable in all rat tissues investigated. The optimal incubation temperature for phospholipase D was 30°C, with a break point at 16.1°C in an Arrhenius plot.
Dopamine Inhibition of the Release of Endogenous Acetylcholine from Corpus Striatum and Cerebral Cortex in Tissue Slices and Synaptosomes: A Presynaptic Response?
Authors: de Belleroche J. , Coutinho‐Netto J. , Bradford H. F.
Published: October 2006

Abstract: The effect of dopamine on the release of endogenous acetylcholine from striatal slices and synaptosomes and from cerebral cortex synaptosomes was studied. K+ (56 mM) and veratrine (75 μM) increased the release of acetylcholine from striatal slices by 3.7 and 3.3 times the resting release, respectively. The effect of veratrine was completely abolished by tetrodotoxin (1 μM). Dopamine (10−6 to 10−3M) reduced the K+‐evoked release of acetylcholine from striatal slices in a dose‐dependent manner. The resting release of acetylcholine was also significantly reduced by dopamine. Apomorphine (20 μM) significantly reduced the K+‐evoked release of acetylcholine, and both this effect and the inhibition due to dopamine (1 mM) were significantly antagonised by chlorpromazine (20 μM). Dopamine had a similar effect on the release of acetylcholine from striatal synaptosome beds; the resting release was depressed 32% by the presence of dopamine (1 mM). A greater effect of dopamine was seen on the release of acetylcholine from cerebral cortex synaptosome beds, the resting release being reduced by 54% and the K+‐evoked release by 29%. These results are discussed in terms of the possible role of presynaptic dopamine receptors in controlling the release of acetylcholine and the magnitude of their contribution compared with that of the postsynaptic dopamine receptor.
Adenosine Measurement by a Rapid HPLC‐Fluorometric Method: Induced Changes of Adenosine Content in Regions of Rat Brain
Authors: Wojcik W. J. , Neff N. H.
Published: October 2006

Abstract: We describe a rapid, sensitive method to determine brain adenosine content by HPLC. Adenosine is first reacted with chloroacetaldehyde to form fluorescent 1, N6‐ethenoadenosine. The derivative is then separated from interfering compounds by HPLC on a C18 reverse‐phase column and quantitated by fluorometry. We found that adenosine was rather uniformly distributed in nine brain regions of animals killed by microwave radiation. In contrast, there was an increase of adenosine in hippocampus, frontal cortex, and especially striatum of animals killed by decapitation. Moreover, adenosine content increased approximately 10‐fold in the thalamus, mesencephalon, and pons‐medulla if the animals were exposed to CO2 for 1 min before they were killed by microwave radiation. Our method should be a useful aid for providing new information about the metabolic and proposed transmitter roles of brain adenosine.
Role of Neuronal Signal Input in the Down‐Regulation of Central Noradrenergic Receptor Function by Antidepressant Drugs
Authors: Janowsky Aaron , Steranka Larry R. , Gillespie David D. , Sulser Fridolin
Published: October 2006

Abstract: Rats with unilateral lesions of the locus coeruleus were used to study the role of norepinephrine (NE) signal input in the down‐regulation by antidepressants of the noradrenergic cyclic AMP‐generating system in the cortex. Chronic administration of both desipramine (blockade of NE reuptake) and iprindole (no blockade of NE reuptake) reduced the cyclic AMP response to NE on the nonlesioned side, but had little or no effect on the lesioned side. The results indicate that NE signal input and thus the formation of the NE‐receptor complex are prerequisites for inducing noradrenergic subsensitivity.
Simultaneous Determination of 3,4‐Dihydroxyphenylalanine, 5‐Hydroxytryptophan, Dopamine, 4‐Hydroxy‐3‐Methoxyphenylalanine, Norepinephrine, 3,4‐Dihydroxyphenylacetic Acid, Homovanillic Acid, Serotonin, and 5‐Hydroxyindoleacetic Acid in Rat Cerebrospinal Fluid and Brain by High‐Performance Liquid Chromatography with Electrochemical Detection
Authors: Wagner Joseph , Vitali Pierre , Palfreyman Michael G. , Zraika Monique , Huot Sylvie
Published: October 2006

Abstract: A method using reversed‐phase ion‐pair high‐performance liquid chromatography with electrochemical detection for the simultaneous determination of tryptophan (TRP), 3,4‐dihydroxyphenylalanine (DOPA), and their metabolites in whole brain, small‐brain parts, and cerebrospinal fluid of rats has been developed. The sample preparation requires only homogenization in perchloric acid and centrifugation before injection onto the column. With a LiChrosorb RP‐18 (10 μm) column and a mobile phase consisting of a phosphate (NaH2PO4, 0.1 M)‐methanol mixture with octylsulfonate (2.6 × 10−3M) at pH 3.35 and 26°C, the separation of DOPA, dopamine, norepinephrine, 3,4‐dihydroxyphenylacetic acid, homovanillic acid, 4‐hydroxy‐3‐methoxyphenylalanine, TRP, 5‐hydroxytryptophan (SHTP), serotonin, and 5‐hydroxyindole‐acetic acid was achieved. The method has been applied to study the effect of α‐monofluoromethyldopa alone and in combination with L‐DOPA or L‐5‐HTP, on the catechol and 5‐OH indole levels in brain and CSF of the rat.