bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of Ornithine Decarboxylase Antizyme in Mouse Brain
Authors: Hietala Oili A. 
Published: October 2006

Abstract:Ornithine decarboxylase, the rate‐limiting enzyme in polyamine synthesis, is known to be regulated by a macromolecular inhibitor, termed antizyme, in a number of cellular systems. The present results show that the antizyme is also a functional component of polyamine metabolism in the brain. It could be demonstrated both in normal randomly selected mice and in animals which had been subjected either to intracerebroventricular injection of saline, which is known to cause a transient activation of ornithine decarboxylase, or to l,3‐diamino‐2‐propanol, an antizyme‐inducing agent. When compared to tissues or cell systems studied so far, the cytosol fraction from mouse brain homogenate appeared to contain an exceptionally high amount of antizyme, that was bound to some material other than active ornithine decarboxylase. This feature was seen in all the animal groups studied, being most prominent after saline injection, when the amount of dissociable antizyme exceeded 14‐fold the corresponding released ornithine decarboxylase activity. In untreated animals the excess was about eightfold and after 1,3‐diamino‐2‐propanol about fivefold.
Ceramide Synthesis from Free Fatty Acids in Rat Brain: Function of NADPH and Substrate Specificity
Authors: Singh Inderjit 
Published: October 2006

Abstract:At the subcellular level, the synthesis of ceramide from free lignoceric acid and sphingosine in brain required reconstituted enzyme system (particulate fraction, heat‐stable and heat‐labile factors) and pyridine nucleotide (NADPH). The mitochondrial electron transfer inhibitors (KCN and antimycin A), energy uncouplers (oligomycin and 2,4‐dinitrophenol), and carboxyatractyloside, which prevents the transport of ATP and ADP through the mitochondrial wall, inhibit the synthesis of ceramide in the presence of NADPH but have very little effect in the presence of ATP. Similar to the synthesis of ceramide, the synthesis of ATP from NADPH and NADH by the particulate fraction also required cytoplasmic factors (heat‐stable and heat‐labile factors). Moreover, ATP, but not its analog (AMP‐CH2‐P‐O‐P), can replace NADPH, thus suggesting that the function of the pyridine nucleotide is to provide ATP for the synthesis of ceramide. The cytoplasmic factors were not required for the synthesis of ceramide in the presence of ATP. The maximum velocity for synthesis of ceramide from free fatty acids of different chain lengths (C16‐C26) was bimodal, with maxima around stearic acid (C18) and behenic acid (C22). The relative rate of synthesis of ceramide parallels the relative distribution of these fatty acids in brain cerebrosides and sulfatides.
Purification and Characterization of Two Distinct Isozymes of Protein Carboxymethylase from Bovine Brain
Authors: Aswad Dana W. , Deight Elizabeth A. 
Published: October 2006

Abstract:Protein carboxymethylase (EC 2.1.1.24) from cytosol of bovine brain was found to exist as two apparent isozymes that could be separated by chromatography on DEAE‐cellulose at pH 8.O. Rechromatography of the two forms, designated PCM I and PCM II, indicated that they are not interconvertible. Both enzymes have a molecular weight of 24,300 by sodium dodecyl sulfate‐polyacryl‐amide gel electrophoresis. PCM I consists mainly of one isoelectric form, pI 6.5, whereas PCM II resolves into two forms of pI 5.6 and 5.7. The relative amounts of PCM I and PCM II show a marked tissue dependence. Brain has approximately twice as much PCM I as II, whereas liver contains only the type II enzyme. The two enzymes were found to have similar substrate specificities when tested with five different methyl‐accepting proteins. Synapsin I, a basic protein associated with synaptic vesicles, was found to be an excellent methyl‐accepting protein with regard to its Km (1.2 μM), but it exhibited a low stoichiome‐try of methyl incorporation.
Inhibition by Quinacrine of Depolarization‐Induced Acetylcholine Release and Calcium Influx in Rat Brain Cortical Synaptosomes
Authors: Baba Akemichi , Ohta Akira , Iwata Heitaroh 
Published: October 2006

Abstract:The effects of quinacrine on depolarization‐induced [3H]acetylcholine (ACh) release and 45Ca2+ influx were examined in rat brain cortical synaptosomes. Quinacrine significantly reduced the stimulated release of [3H]ACh by high K+ and veratridine without affecting the spontaneous efflux from the preloaded synaptosomes. Quinacrine had no effect on ionophore A23187‐induced release of [3H]ACh from the synaptosomes. Quinacrine (100 μM) markedly diminished the stimulated Ca2+ influx by veratridine and high K+ but not that by “Na+‐free.” Trifluoperazine, a potent calmodulin antagonist, inhibited both Ca2+ influx and ACh release induced by the depolarizing agents. Inhibitory potencies of the two drugs on ACh release and Ca2+ influx were compared with the antagonism of calmodulin by two drugs, suggesting that the inhibition of depolarization‐induced Ca2+ influx and ACh release by these drugs could not be explained by the antagonism of calmodulin.
Histamine Turnover in the Brain of Different Mammalian Species: Implications for Neuronal Histamine Half‐Life
Authors: Nishibori Masahiro , Oishi Ryozo , Saeki Kiyomi 
Published: October 2006

AbstractThe turnover of neuronal histamine (HA) in nine brain regions and the spinal cord of the guinea pig and the mouse was estimated and the values obtained were compared with data previously obtained in rats. The size of the neuronal HA pool was determined from the decrease in HA content, as induced by (S)‐α‐fluoromethylhistidine (α‐FMH), a suicide inhibitor of histidine decarboxylase. The ratios of neuronal HA to the total differed with the brain region. Pargyline hydrochloride increased the tele‐methylhistamine (t‐MH) levels linearly up to 2 h after administration in both the guinea pig and the mouse whole brain. Regional differences in the turnover rate of neuronal HA, calculated from the pargylineinduced accumulation of t‐MH, as well as in the size of the neuronal HA pool, were more marked in the mouse than in the guinea pig brain. The hypothalamus showed the highest rate in both species. There was a good correlation between the steady‐state t‐MH levels and the turnover rate in different brain regions. Neither the elevation of the t‐MH levels by pargyline nor the reduction of HA by α‐FMH was observed in the spinal cord, thereby suggesting that the HA present in this region is of mast cell origin. The half‐life of neuronal HA in different brain regions was in the range of 13‐38 min for the mouse and 24‐37 min for the guinea pig, except for HA from the guinea pig hypothalamus, which had an extraordinarily long value of 87 min. These results suggest that there are species differences in the function of the brain histaminergic system.
Subcellular Distribution of Opioid Peptides in Rat Hypothalamus and Pituitary
Authors: Molineaux C. J. , Rosenberger J. G. , Cox B. M. 
Published: October 2006

AbstractHomogenates of rat anterior lobe (AL) and neurointermediate lobe (NIL) pituitary and rat hypothalamus were subjected to subcellular fractionation and density gradient centrifugation. The subcellular distribution of immunoreactive dynorophin A (ir‐Dyn A) in NIL was found to be similar to that of ir‐arginine vasopressin (ir‐AVP). ir‐Dyn A migrated as a discrete band on sucrose density gradients, which corresponded in sedimentation rate to that of ir‐AVP, suggesting that these two peptides are stored within organelles of similar size and density. Two other products of prodynorphin, ir‐α‐neoendorphin ir‐α‐nEND) and ir‐Dyn A‐(1–8) also comigrated with ir‐AVP. ir‐[Leu5]‐enkephalin (ir‐LE), which may be a product of prodynorphin or proenkephalin, was also found to migrate in this region of the gradient. When a homogenate of rat hypothalamus was prepared using a method that has been developed for synaptosome isolation, ir‐Dyn A was found to comigrate with Na+/K+‐activated adenosine triphosphatase (Na/K‐ATPase), a synaptosomal marker enzyme. Using a more concentrated homogenate ir‐Dyn A was found to migrate to a less dense region where peptide‐containing synaptic vesicles have previously been localized. When a synaptosomal preparation was lysed in hypotonic solution a shift was seen in the migration rate of (ir‐Dyn A to this region of the gradient (containing putative synaptic vesicles). Thus the bulk of hypothalamic dynorphin appears to be present within synaptosotne‐like structures which, upon lysis, release a less dense, smaller subcellular organelle corresponding in sedimentation characteristics to other types of peptide‐containing synaptic vesicles. Using either method ir‐AVP migrated to a position that was different from that of ir‐Dyn A and was unaffected by lysis conditions. These results indicate that the majority of the dynorphin in the hypothalamus is not stored with vasopressin at the subcellular level. Immunoreactivities associated with Dyn A‐(4–8), α‐nEND, LE, and [Met5]‐en‐kephalin‐Arg6‐Phe7 (ME‐RF) in hypothalamus were all found to migrate with ir‐Dyn A and all are shifted to approximately the same location by lysis. Thus all of the prodynorphin and proenkephalin products examined appear to be stored within synaptic vesicle‐like organelles present primarily within nerve terminals in the hypothalamus.
Rat Brain S100b Protein: Purification, Characterization, and Ion Binding Properties. A Comparison with Bovine S100b Protein
Authors: Baudier Jacques , Labourdette Gérard , Gerard Dominique 
Published: October 2006

Abstract:We purified to homogeneity rat brain S100b protein, which constitutes about 90% of the soluble S100 protein fraction. Purified rat S100b protein comigrates with bovine S100b protein in nondenaturant system electrophoresis but differs in its amino acid composition and in its electrophoretic mobility in urea‐sodium dodecyl sulfate‐polyacrylamide gel with bovine S100b protein. The properties of the Ca2+ and Zn2+ binding sites on rat S100b protein were investigated by flow dialysis and by fluorometric titration, and the conformation of rat S100b in its metal‐free form as well as in the presence of Ca2+ or Zn2+ was studied. The results were compared with those obtained for the bovine S100b protein. In the absence of KCI, rat brain S100b protein is characterized by two high‐affinity Ca2+ binding sites with a KD of 2 + 10−5M and four lower affinity sites with KD about 10−4M. The calcium binding properties of rat S100b protein differ from bovine S100b only by the number of low‐affinity calcium binding sites whereas similar Ca2+ ‐induced conformational changes were observed for both proteins. In the presence of 120 mM KCI rat brain S100b protein bound two Zn2+‐ ions/mol of protein with a KD of 10 −7M and four other with lower affinity (KD+ 10−6M). The occupancy of the two high‐affinity Zn2+ binding sites was responsible for most of the Zn2+‐induced conformational changes in the rat S100b protein. No increase in the tyrosine fluorescence quantum yield after Zn2+ binding to rat S100b was observed. Such results significantly differ from that obtained with bovine S100b protein, which on binding of eight Zn2+ equivalents/mol undergoes maximal conformational changes associated with a sixfold increase of the tyrosine fluorescence quantum yield. Finally, we report in this work that zinc binding on rat S100b protein regulates calcium binding by increasing the calcium affinity of the protein and reducing the antagonistic effect of K+ on calcium binding.
Amino Acid Sequence of Porcine Myelin Basic Protein
Authors: Kira Jun‐ichi , Deibler Gladys E. , Krutzsch Henry C. , Martenson Russell E. 
Published: October 2006

Abstract:The myelin basic protein (BP) of pig brain was cleaved into its constituent tryptic peptides and the amino acid composition of each was determined. Those tryptic peptides that had not been sequenced previously were cleaved with dipeptidyl peptidases and the resulting dipeptides were trimethylsilated, separated by gas chromatography, and identified by mass spectrometry. Carboxypeptidases B and Y were used to establish the COOH‐terminal sequences of some of the tryptic peptides; one tryptic peptide (sequence 76–92) was cleaved with thermolysin and the thermolytic peptides were analyzed. From the results of the present study together with those reported previously, it has been possible to determine the complete amino acid sequence of the protein. The protein consists of 172 residues and has a theoretical molecular weight of 18,604. Its amino acid sequence is identical with that reported for the homologous bovine protein with the following exceptions: Ser replaces (bovine) Ala2; His‐Gly is inserted between Arg9 and Ser10; Ala replaces Ser45; His and Gly replace Gly76 and His77, respectively; Pro replaces Ser131 and Ser135; Ala is inserted between Gly142 and His143; and Gin replaces His143.
Identification of the Adenosine Uptake Sites in Guinea Pig Brain
Authors: Jarvis Simon M. , Ng Andrew S. 
Published: October 2006

Abstract:Nitrobenzylthioinosine (NBMPR), a potent and specific inhibitor of nucleoside transport, was employed as a photolabile probe of the adenosine transporter in guinea pig brain membranes. Reversible, high‐affinity binding of [3H]NBMPR to a crude preparation of guinea pig brain membranes was demonstrated (apparent KD 0.075 ± 0.012 nM; Bmax values of 0.24 ± 0.04 pmol/mg protein). Adenosine, uridine, dipyridamole, and nitrobenzylthioguanosine inhibited high‐affinity binding. Low concentrations of cyclohexoadenosine (10–300 nM) had no effect on NBMPR binding. These properties of the high‐affinity NBMPR binding sites were consistent with NBMPR binding to the nucleoside transport protein. Exposure of brain membranes in the presence of [3H]NBMPR and dithiothreitol, a free‐radical scavenger, to ultraviolet light resulted in covalent incorporation of 3H into polypeptides of apparent MW 66,000–45,000, a value similar to that for the human erythrocyte nucleoside transporter. Covalent attachment of [3H]NBMPR was inhibited by adenosine, dipyridamole, and nitrobenzyl‐thioguanosine.
The Subcellular Distribution of Peptide Histidine Isoleucine Amide‐27‐Like Peptides in Rat Brain and Their Release from Rat Cerebral Cortical Slices In Vitro
Authors: Korchak Diana M. , Gysling Katia , Beinfeld Margery C. 
Published: October 2006

Abstract:The subcellular distribution of peptide histidine isoleucine amide (PHI)‐27‐like peptides (PLP) was investigated in rat cerebral cortex and whole rat brain in comparison with the distribution of vasoactive intestinal peptide (VIP). The highest content of PLP was found in the crude mitochondrial fraction (P2) and was also detected in the microsomal pellet. PLP was recovered in synaptosomes when further fractionation of P2 was performed. This distribution of PLP closely follows that of VIP and is suggestive of possible storage in vesicles at the nerve terminal. Basal release of PLP from rat cerebral cortical slices was below the detection limit of the PHI radioimmunoassay. However, depolarization by 55 mM potassium induced measurable PLP release. This release was calcium‐dependent. These findings support the hypothesis that PLP could play a role in neurotransmission.
GABA‐Modulin: A Synaptosomal Basic Protein that Differs from Small Myelin Basic Protein of Rat Brain
Authors: Vaccarino Flora , Tronconi Bianca M. Conti , Panula Pertti , Guidotti Alessandro , Costa Erminio 
Published: October 2006

Abstract:GABA‐modulin, a basic protein that allosterically inhibits the high‐affinity binding of GABA to its recognition sites, has been extracted and purified from the synaptosomal fraction of rat brain where it represents approximately 0.5% of the total synaptosomal proteins. GABA‐modulin has characteristics in common to the class of highly basic proteins isolated from myelin, in particular to the rat small myelin basic protein (SMBP). However, GABA‐modulin is located selectively in synaptosomes, whereas the SMBP is located in myelin. Moreover, synaptosomal GABA‐modulin is different from SMBP in amino acid composition (it contains more Glx and Lys and fewer Arg residues) and in apparent molecular weight (17,000 and 15,000 for GABA‐modulin and SMBP, respectively). Synaptosomal GABA‐modulin fails to bind [3H]muscimol per se but noncompetitively inhibits (IC50˜ 0.5 μM) the binding of [3H]muscimol to purified synaptic membranes. Cyanogen bromide treatment generated a 13,000 MW major fragment from both SMBP and GABA‐modulin. These two fragments were compared and showed differences in amino acid composition and sequence. Moreover, the peptide maps generated from GABA‐modulin and SMBP by trypsin and staphylococcal V8 protease digestion are different. The high concentration of GABA‐modulin in synaptosomal membranes, its high potency in the inhibition of GABA binding, and its neuronal specificity suggest that GABA‐modulin plays an important role in neuronal membrane function linked to the modulation of GABA and perhaps other neurotransmitter receptors.
A Study on Erythrocyte Membrane Plasmalogen in Myotonic Dystrophy
Authors: Antoku Yasunobu , Sakai Tetsuo , Tsukamoto Kohsuke , Goto Ikuo , Iwashita Hiroshi , Kuroiwa Yoshigoro 
Published: October 2006

Abstract:Phospholipid classes that included plasmalogens of erythrocyte membranes in seven myotonic dystrophy (MyD) patients and seven normal controls were analyzed by HPLC. No significant difference in phospholipid classes was found between patients with MyD and normal controls, but there was a visible difference in peak profiles of compounds of the phosphatidylethanolamine class. In the study of plasmalogens, we used two preparation methods: exposure to HCl and deacylation with mild alkaline. The area ratio of the plasmalogen form to the diacyl form in the phosphatidylethanolamine class of MyD erythrocyte membranes was significantly lower than that of normal controls. Fatty acid analyses showed that fatty acids of both phosphatidylethanolamine subclasses have less unsaturation in MyD.
Translational Activity of mRNA Coding for Cytoskeletal Brain Proteins in Newborn and Adult Mice: A Comparative Study
Authors: Darmon Michèle C. , Paulin Denise J. 
Published: October 2006

Abstract:Translational activity of mRNA coding for cytoskeletal brain proteins was used to determine the relative abundance of the mRNA in the brains of newborn and adult mice. mRNA was translated in a cell‐free system containing rabbit reticulocyte factors. The products of translation were analyzed by two‐dimensional gel electrophoresis and characterized by peptide map analysis. Comparison of the products of translation from newborn and from adult brain mRNA shows a 50% decrease in actin and tubulin from newborn to the adult stage. In contrast, the 70 kd neurofilament protein and glial fibrillary acidic protein show a twofold increase in the adult stage. The heat‐shock protein HSP70 increases slightly (30%) whereas the brain isozyme of creatine kinase and the heat‐shock protein HSP90 are three times as high in adult subject as in newborns.
Immunological Characterization of Secretory Proteins of Chromaffin Granules: Chromogranins A, Chromogranins B, and Enkephalin‐Containing Peptides
Authors: Fischer‐Colbrie R. , Frischenschlager I. 
Published: October 2006

Abstract:The soluble proteins of bovine chromaffin granules can be resolved into about 40 proteins by twodimensional electrophoresis. Use of several antisera enabled us to characterize most of these proteins with the immune replica technique. An antiserum against dopamine β‐hydroxylase reacted with one protein of Mr 75,000. Met‐enkephalin antisera labeled eight proteins of Mr 23,000–14,000. A new method was developed to obtain highly purified chromogranin A for immunization. The antiserum reacted with chromogranin A and several smaller proteins of similar pI. This specific antiserum did not react with a second family of hitherto undescribed proteins, which we propose to call chromogranins B. An antiserum against these proteins was raised. It labeled several proteins ranging in Mr from 100,000 to 24,000 and focusing at pH 5.2. Subcellular fractionation established that chromogranins B are specifically localized in chromaffin granules of several species. They are secreted from the adrenal medulla during cholinergic stimulation. We conclude that apart from dopamine β‐hydroxylase chromaffin granules contain three families of immunologically unrelated proteins.
Cerebellum Lipids in Rats After Chronic Ethanol Treatment
Authors: Vrbaški SneŽana R. , Ristić Milosav 
Published: October 2006

Abstract:Eighteen male Wistar rats weighing approximately 200 g were divided into three groups of six animals each. The experimental animals were maintained on nutritionally complete diets in which ethanol comprised 45% of the available energy. Control animals were pair‐fed an equivalent diet in which sucrose was substituted isocalorically for ethanol. An additional control group received unlimited access to standard pelleted laboratory food and water. The investigations were carried out over 24 weeks. The effects on phospholipid, monogalactosyl glycolipid, and ganglioside composition after 24 weeks of feeding 43% alcohol were studied. There is abundant evidence that the changes in the cerebellum membrane phospholipids (phosphatidylethanolamine and phosphatidylcholine), gangliosides (GTlb), and myelin lipids (phosphatidylserine, sphingophospholipid, phosphatidylinositol, cerebrosides with hydroxy fatty acids, sulfoglycolipids, and monosialoganglioside GM1) occur as a result of chronic ethanol treatment.
Studies on the Alkylation of Choline Acetyltransferase by Choline Mustard Aziridinium Ion
Authors: Rylett R. Jane , Colhoun E. Howard 
Published: October 2006

Abstract:Although a potent irreversible inhibitor of high‐affinity choline transport in rat brain synaptosomes, choline mustard aziridinium ion (ChM Az) appeared to be a relatively weak inhibitor of choline acetyltransferase (ChAT) in rat brain homogenates, and evidence for irreversible binding of this compound to the enzyme had not been established. Accordingly, the irreversible inactivation of partially purified rat brain ChAT by ChM Az was studied. This compound is a rather weak inhibitor of the enzyme, with 50% inhibition of ChAT activity achieved following 30 min incubation at 37°C with 0.6 mM ChM Az. This result indicates that although ChM Az has affinity for many nucleophiles there was little diluting effect of the inhibitor in the crude brain homogenate which could be attributed to such reactions (50% inhibition caused by 1.8 mM ChM Az following 10 min incubation). Although the initial binding of ChM Az to ChAT may be of a competitive nature, irreversible bond formation resulted. The time‐dependent alkylation reaction conformed to pseudo‐first‐order kinetics with an observed forward rate constant (kobs) of 0.173 min−1; the half‐time (t1/2) for irreversible binding was about 4 min. The irreversible inactivation of ChAT by ChM Az would appear to be slower than the alkylation of high‐affinity choline carriers in synaptosomes by this compound, and the relatively weak inhibitory action of ChM Az against either partially purified ChAT or ChAT activity in crude rat brain homogenates is in striking contrast to previous evidence that ChAT in intact synaptosomes was inhibited irreversibly by lower concentrations of the inhibitor.