Involvement of mitogen-stimulated p70-S6 kinase in the development of sensitization to the methamphetamine-induced rewarding effect in rats.

The neural plasticity associated with behavioral sensitization following repeated administration of a psychostimulant methamphetamine (METH) is thought to require synthesis of new proteins. The aim of the present study was to investigate the role of p70-S6 kinase (p70-S6K) phosphorylation, which contributes to the selective translation of a unique family of mRNA, in mediating both the METH-induced rewarding effect and its sensitization. An intra-nucleus accumbens (N.Acc.) pre-injection with 0.025 pmol/rat of a selective p70-S6K inhibitor rapamycin failed to affect the METH-induced conditioned place preference. However, this treatment clearly abolished the development of sensitization of the METH-induced conditioned place preference. Consistent with the behavioral assay, the level of the immunoreactivity of phosporylated-p70-S6K was not changed in the cytosolic fraction of the N.Acc. obtained from rats that had revealed the METH-induced rewarding effect. In contrast, the immunoreactivities in the cytosolic preparation for Western blotting and immunohistochemical density of phosphorylated-p70-S6K were significantly increased in the N.Acc. obtained from METH-sensitized rats as compared with those with chronic saline treatment. However, the immunoreactivities of phosphorylated-extracellular signal-regulated kinase and phosphorylated-ribosomal S6 protein were not significantly altered in the N.Acc. under the same condition. The present data provide evidence for the change in the translation rate, which can be regulated by S6K phosphorylation, in the N.Acc. during the development of sensitization to METH-induced rewarding effects in rats.

Implications of protein kinase C in the nucleus accumbens in the development of sensitization to methamphetamine in rats.

Repeated treatment with methamphetamine leads to an enhancement in the methamphetamine-induced dopamine release and its related behaviors. This phenomenon is called sensitization or reverse tolerance. Protein kinase C (PKC) controls numerous signaling cascades by virtue of its ability to phosphorylate target proteins that include other kinases. The purpose of study was then to investigate the implication of PKC in the development of sensitization to the rewarding effect and to the extracellular dopamine release induced by methamphetamine in rats. The conditioned place preference paradigm and in vivo microdialysis assay were performed in the present study. An intra-nucleus accumbens injection of a selective PKC inhibitor chelerythrine chloride abolished the enhancement of the methamphetamine-induced place preference following repeated treatment with methamphetamine. Furthermore, intra-nucleus accumbens injection of chelerythrine chloride blocked the development of sensitization to dopamine release and to the decrease in the major dopamine metabolites, 3'4-dihydroxyphenylacetic acid and homovanillic acid, in the nucleus accumbens induced by repeated methamphetamine treatment. Under these conditions, the immunoreactivity of the cytosolic phosphorylated conventional- or classic-type PKC in the limbic forebrain region including the nucleus accumbens was slightly, but significantly increased in methamphetamine-sensitized rats. The present data provide evidence for the implication of PKC in the nucleus accumbens in the development of sensitization to the methamphetamine-induced rewarding effect, dopamine release and inhibition of dopamine metabolism/re-uptake in rats.

Mouse liver dihydrodiol dehydrogenases. Identity of the predominant and a minor form with 17 beta-hydroxysteroid dehydrogenase and aldehyde reductase.

A major and a minor form of dihydrodiol dehydrogenase were co-purified with 17 beta-hydroxysteroid dehydrogenase and aldehyde reductase, respectively, to apparent homogeneity from liver cytosol of male ddY mice. The activities of dihydrodiol dehydrogenase and testosterone dehydrogenase or aldehyde reductase of the two enzyme forms comigrated electrophoretically. The major form of the enzyme oxidized 17 beta-hydroxysteroids and nonsteroidal alicyclic alcohols and reduced 17-ketosteroids and various synthetic carbonyl compounds, showing higher affinity for steroids than for xenobiotics. The activity of this enzyme form toward benzene dihydrodiol and testosterone exhibited identical thermostability and susceptibility to inhibition by quercitrin, SH-reagents, nonsteroidal estrogens and anti-inflammatory agents. On the other hand, the minor form of the enzyme, which oxidized benzene dihydrodiol but not 17 beta-hydroxysteroids, also reduced various aldehydes well and was specifically inhibited by barbiturates and sorbinil. These results indicate that the major form of dihydrodiol dehydrogenase is identical to 17 beta-hydroxysteroid dehydrogenase and the minor enzyme form to aldehyde reductase.

Dihydrodiol dehydrogenases in guinea pig liver.

Four major and four minor dihydrodiol dehydrogenases, with similar apparent molecular weights of 28,000 to 34,000 but with different charges, were purified from male guinea pig liver cytosol. One of the minor enzymes catalyzed only the oxidation of benzene dihydrodiol with a high Km value of 5.0 mM and was identified immunologically with aldehyde reductase. The other enzymes oxidized xenobiotic alicyclic alcohols and 17 beta-hydroxysteroids as well as benzene dihydrodiol. These enzymes exhibited higher affinity for 17 beta-hydroxysteroids than for alicyclic alcohols and benzene dihydrodiol, and immunologically cross-reacted with testosterone 17 beta-dehydrogenase purified from the same source. Four major enzymes and one minor with Km values for benzene dihydrodiol of about 0.2 mM, possessed specificity for 5 beta-androstane--17 beta-hydroxysteroids and dual cofactor requirement, whereas the other two minor enzymes with high Km values of over 5 mM showed apparent NADP and 5 alpha-androstane specificity. The dihydrodiol dehydrogenase activity was localized in the cytosol of liver. The results indicate that the hepatic oxidation of dihydrodiols in the guinea pig is mediated by cytosolic testosterone 17 beta-dehydrogenase isozymes and aldehyde reductase. Testosterone 17 beta-dehydrogenase immunologically identical to the liver enzymes was detected only in kidney, whereas aldehyde reductase was detected in all tissues of the guinea pig.

Stimulatory effect of dibutyryl cyclic GMP on acid secretion in mouse isolated stomach and on histamine release in gastric mucosal cells.

We previously reported that endogenous nitric oxide (NO) is involved in the peripheral control of gastric acid secretion induced by some secretagogues, and that endogenous NO is involved in the acid secretion process via histamine release from histamine-containing cells. However, the stimulus-secretion coupling in the cells remains to be clarified. In the present study, we investigated the effect of dibutyryl cyclic GMP on gastric acid secretion in mouse isolated stomach and on histamine release in gastric mucosal cells, in comparison with those of dibutyryl cyclic AMP. Dibutyryl cyclic GMP (300 microM) produced a slight but significant increase of gastric acid secretion, which was completely inhibited by the histamine-H2 receptor antagonist famotidine. In contrast, dibutyryl cyclic GMP (1 mM) markedly inhibited histamine-induced acid secretion. Dibutyryl cyclic AMP (100 microM) produced a sustained increase of gastric acid secretion. The pretreatment with famotidine partially inhibited dibutyryl cyclic AMP-induced gastric acid secretion. Dibutyryl cyclic GMP and dibutyryl cyclic AMP significantly increased the histamine release from gastric mucosal cells. These results suggest that both intracellular cyclic GMP and cyclic AMP act as second messengers for histamine release in the histamine-containing cells, probably ECL cells. On the other hand, in gastric parietal cells, cyclic AMP has a stimulatory effect on gastric acid secretion, whereas cyclic GMP has an inhibitory effect.

Inhibitory effect of N(omega)-nitro-L-arginine on gastric secretion induced by secretagogues and vagal stimulation in the isolated stomach.

The involvement of endogenous nitric oxide (NO) in the control of gastric acid secretion induced by some secretagogues was studied in the mouse isolated whole stomach. The gastric acid secretion induced by McNeil A-343 [4-[[[(3-chlorophenyl)amino]carbonyl]oxy]-N,N,N-trimethyl-2-butyn- 1-aminium chloride], a muscarinic M1 receptor agonist, pentagastrin or electrical vagus nerve stimulation was markedly inhibited by pretreatment with the NO synthase inhibitor N(omega)-nitro-L-arginine (L-NNA). This inhibitory effect of L-NNA was reversed by L-arginine, but not by D-arginine. Histamine-induced gastric acid secretion was not influenced by treatment with L-NNA. Famotidine completely inhibited the gastric acid secretion induced by McNeil A-343, pentagastrin or electrical vagus nerve stimulation, showing that these stimulations induced gastric acid secretion mainly through histamine release from histamine-containing cells in the gastric mucosa. Moreover, the pentagastrin- and bethanechol-induced histamine release from gastric mucosal cells was significantly inhibited by L-NNA. The NO donor, sodium nitroprusside, at a concentration not affecting histamine-induced gastric acid secretion, increased the acid secretory response, and this response was inhibited by famotidine. These results suggest that endogenous NO is involved in the gastric acid secretion via histamine release from histamine-containing cells.

Stimulatory effects of nitric oxide donors on gastric acid secretion in isolated mouse stomach.

We previously reported on the stimulatory role of endogenous nitric oxide (NO) in gastric acid secretion. In the present study, we investigated the effects of NO donors on acid secretion in isolated mouse stomach. Nitroprusside (100 microM(-1) x mM) inhibited the gastric acid secretion induced by histamine (500 microM) in a concentration-dependent manner. In addition, nitroprusside abolished the acid secretion induced by bethanechol (100 microM) and by electrical stimulation (10 Hz) of the vagus nerve. On the other hand, nitroprusside, 75 microM, which did not affect the acid secretion induced by histamine, itself elicited an increase in acid secretion. The acid secretion induced by 75 microM nitroprusside was inhibited by 10 microM famotidine, a histamine H2 receptor antagonist. These results suggest that NO donors at high doses act on gastric parietal cells, resulting in inhibition of the stimulated acid secretion, and, at lower doses, facilitate histamine release from histamine-containing cells, leading to the increased acid secretion.

Separation of carboxylic acids on a weakly acidic cation-exchange resin by ion-exclusion chromatography.

The separation of various carboxylic acids was performed on a polymethacrylate-based weakly acidic cation-exchange resin (TSKgel OApak-A) using ion-exclusion chromatography under the acidic elution conditions. When a diluted sulfuric acid solution was used as the eluent, highly sensitive conductimetric detection of carboxylic acids was achieved without increasing the background conductance of the eluent. This method was more sensitive than using benzoic acid eluent and enabled a good resolution of dicarboxylic as well as monocarboxylic acids. The addition of 5-20% methanol to the eluent considerably reduced the retention times of carboxylic acids with hydrophobic nature.

Suppressed electrostatic ion chromatography with tetraborate as eluent and its application to the determination of inorganic anions in snow and rainwater.

Tetraborate is investigated as the eluent ion for suppressed electrostatic ion chromatography (EIC) using a zwitterionic stationary phase. Good separation of a range of inorganic anions (SO4(2-), Cl-, NO3-, Br-, NO3-, ClO3-, and I-) was obtained, with detection limits for highly conducting ions (SO4(2-), Cl-, NO2-, Br- , and NO3-) being less than 8 x 10(-8) M, and for weakly conducting anions (ClO3- and I-) being 2.7 x 10(-7) and 5.8 x 10(-7) M, respectively. Calibration curves were linear up to 1.8 mM of each analyte. Retention times were found to increase with increasing eluent concentration and a linear relationship was observed between log k' and log[Na2B4O7] for all analytes. This behaviour is attributed to the progressive formation of a binary electrical double layer at the surface of the zwitterionic stationary phase. Retention times of analytes could be manipulated by varying the concentration of the eluent. This new suppressed-EIC system was applied to the determination of inorganic anions (SO4(-2) , CI-, NO3-, NO2-, and Br-) in snow and rainwater samples.

Electrostatic ion chromatography of polarizable anions in saline waters with N-[2-[acetyl(3-sulfopropyl)amino]ethyl]-N,N-dimethyldodecanaminium hydroxide (ammonium sulfobetaine-1) as the stationary phase and a dilute electrolytic solution as the mobile phase.

A new type of zwitterionic surfactant, N-{2-[acetyl(3-sulfopropyl)amino]ethyl}-N,N-dimethyldodecanaminium hydroxide (ammonium sulfobetaine-1), with a greater distance between the two charged groups, was used as the stationary phase for electrostatic ion chromatography (EIC) of polarizable anions (e.g., thiocyanate, iodide and nitrate) in saline water samples. The targeted species (polarizable anions) were baseline separated using this type of zwitterionic surfactant as the stationary phase, but the highly polarizable species (iodide and thiocyanate) were eluted faster (compared with the results obtained using N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate, C12N3S, with a shorter distance between the two charged groups, as the stationary phase). In other words, the extent of binding of the highly polarizable anion (iodide and thiocyanate) was found to be smaller when using ammonium sulfobetaine-1 as the stationary phase. This provides a rapid but effective method for the analysis of highly polarizable anions in saline water samples. The results for the successful detection of iodide in seawater demonstrates the usefulness of this new type of zwitterionic surfactants for EIC.

Manipulation of separation selectivity of inorganic anions in electrostatic ion chromatography by the use of mixed cationic-zwitterionic micelles as the column coating solution.

This paper describes an electrostatic ion chromatographic system in which the separation selectivity for inorganic anions, especially for sulfate and phosphate, could be manipulated by altering the molar ratio of the zwitterionic and cationic surfactants in the column coating solution used to prepare the stationary phase. The zwitterionic surfactant used for this study was 3-(N,N-dimethyltetradecylammonio)propanesulfonate (Zwittergent-3-14) and the cationic surfactant was tetradecyltrimethylammonium (TTA). Using a reversed-phase C18 column (250x4.6 mm I.D.) coated with 10/10 (mM/mM) of TTA/Zwittergent-3-14 mixed micelles as the stationary phase and either NaHCO3 or Na2CO3 aqueous solution as the eluent, together with suppressed conductivity detection, baseline separation of seven model inorganic anions was obtained. The elution order for those anions was found to be F+ < HPO4(2-) < Cl- < SO4(2-) < NO2- < Br- < NO3-. Under the same conditions but using 1/10 (mM/mM) of TTA/Zwittergent-3-14 mixed micelles as the column coating solution, the elution order for these model ions was F- < HPO4(2-) < SO4(2-) < Cl- < NO2- < Br- < NO3-. The early elution of phosphate and sulfate is a unique attribute of this system. Detection limits for F-, HPO4(2-), Cl-, SO4(2-), NO2-, Br- and NO3- (S/N=3, sample injection volume 100 microl) were 0.11, 0.12, 0.12, 0.18, 0.49, 0.49, 0.52 microM, respectively.

Simultaneous ion-exclusion/cation-exchange chromatography of anions and cations in acid rain waters on a weakly acidic cation-exchange resin by elution with sulfosalicylic acid.

A simple, selective, and sensitive method for the simultaneous determination of anions (sulfate, nitrate, and chloride) and cations (sodium, ammonium, potassium, magnesium, and calcium) in acid rain waters was developed using ion-exclusion/ cation-exchange chromatography with conductimetric detection. A weakly acidic cation-exchange resin column (Tosho TSKgel OA-PAK-A) and a sulfosalicylic acid-methanol-water eluent was used. With a mobile phase comprising 1.25 mM sulfosalicylic acid in methanol-water (7.5:92.5) at 1.2 ml/min, simultaneous separation and detection of the above anions and cations was achieved in about 30 min. Linear calibration plots of peak area versus concentration were obtained over the concentration ranges 0-1.0 mM for anions (R=0.9991) and 0-0.5 mM for cations (R=0.9994). Detection limits calculated at S/N=3 ranged from 4.2 to 14.8 ppb for the anions and from 2.4 to 12.1 ppb for the cations. The reproducibility of retention times was 0.14-0.15% relative standard deviation (RSD) for anions and 0.18-0.31% for cations, and reproducibility of chromatographic peak areas was 1.22-1.75% RSD for anions and 1.81-2.10% for cations. The method was applied successfully to the simultaneous determination of anions and cations in aerosols transported from mainland China to central Japan, as determined by a meteorological satellite data analyzer.

Acid-rain monitoring in east Asia with a portable-type ion-exclusion-cation-exchange chromatographic analyzer.

A monitoring system consisting of a portable-type conductimetric ion-exclusion-cation-exchange chromatographic (CEC) analyzer and a meteorological satellite data analyzer has been investigated for the evaluation of the effects of acid precipitation on natural and urban environments in East Asia. The portable ion-exclusion-CEC analyzer uses a polymethacrylate-based weakly acidic cation-exchange resin column in the H(+)-form and a weak-acid eluent (tartaric acid-methanol-water) and is applied for the simultaneous determination of anions (SO4(2)-, NO3-, and Cl-) and cations (Na+, NH4+, K+, Mg2+, and Ca2+) in precipitation transported from mainland China to central Japan, as mapped by the meteorological satellite data analyzer. Linear calibration graphs of peak area versus concentration for anions and cations were observed in the concentration range 0-1.0 mM for the anions and 0-0.5 mM for the cations. Detection limits at a signal-to-noise ratio of 3 were in the range 5.18-12.1 ppb for the anions and 6.58-16.5 ppb for the cations. The practical utility of this monitoring system is presented.

High-performance ion-exclusion/cation-exchange chromatography of anions and cations in acid rain waters on a weakly acidic cation-exchange resin.

A new method for the simultaneous determination of anions (sulfate, nitrate, and chloride) and cations (sodium, ammonium, potassium, magnesium, and calcium) in acid rain waters was investigated using high-performance ion-exclusion/cation-exchange chromatography with conductimetric detection on a separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin in the hydrogen-form and an eluent comprising 1.5 mM sulfosalicylic acid-6 mM 18-crown-6 at pH 2.6, operated at 1.5 ml/min. Effective separation and highly sensitive conductimetric detection for the anions and the cations was achieved in about 14 min. Since the ionic balance (equivalents of anions/equivalents of cations) of acid rain waters of different pH (4.40-4.67) ranged from 0.97 to 0.94, evaluation of the water quality of acid rain was possible. This method was successfully applied to the simultaneous determination of the anions and the cations in acid rain transported from mainland China and North Korea to central Japan monitored by a meteorological satellite data analyzer.

Effect of a glutamine-enriched diet on small bowel allograft during immunosuppressive therapy.

The effect of an orally administered glutamine-enriched elemental diet was examined following orthotopic small bowel allotransplantation using Brown Norway rats as donors and Lewis rats as recipients. The recipients was treated with FK 506 and randomized to receive glutamine-free elemental enteral diet solution (glutamine-free group), glutamine-enriched elemental diet solution containing 7500 mg of glutamine per 100 g diet (glutamine-enriched group) or standard chow (chow group) ad libitum for 7 d. There were no histological changes due to resection. Weight loss in the glutamine-enriched group was significantly less than that of the chow group. Both plasma glutamine levels and the ratio of glutamine to total amino acids in the homogenate of the graft mucosa of the glutamine-enriched group were significantly higher than those of the glutamine-fee group. Villous height and crypt depth were significantly decreased in the glutamine-free group. The BrdU labeling index in the graft epithelium and alkaline phosphatase activity in the homogenate of the graft mucosa of the glutamine-enriched group were significantly higher than those of the glutamine-free group. Therefore, orally administered glutamine-enriched elemental diet appears to promote the regeneration and differentiation of the graft mucosa following small bowel allotransplantation.

Differential-pulse polarographic determination of N-nitrosoproline in uncooked meat.

Ham and bacon have been analysed for N-nitrosoproline by differential-pulse polarography. Quantitative polarograms without interfering peaks were obtained from ethanol extracts prepared after extensive clean-up which included freeze-drying and column chromatography. Differential-pulse polarography proved sufficiently sensitive to give peaks corresponding to ca. 100 mug of N-nitrosoproline per kg in several commercial samples of cured meat.

A solvent extraction-spectrophotometric determination of bismuth(III) as Tetra-n-butylammonium tetraiodobismuthate.

A solvent extraction-spectrophotometric method has been developed for determination of bismuth in the form of tetra-n-butylammonium tetraiodobismuthate(III). The effects of pH, the concentrations of tetra-n-butylammonium and iodide ions, and the nature and amount of the organic, solvent have been studied. Tetra-n-butylammonium was found to be the most useful cation for extraction of tetraiodobismuthate with chloroform, giving quantitative extraction. The optimum pH is <3, and the extracted species is stable for at least a day at room temperature. Bismuth can be determined at the 10(-5)M level in aqueous solution, the relative standard deviation being 1.7%.

Differential pulse polarographic determination of nitrate in environmental materials.

Nitrate can be determined with reliable accuracy and sensitivity by differential pulse polarography utilizing the catalytic reaction between nitrate and uranyl ion in the presence of potassium sulphate. The differential pulse polarographic peak-height is proportional to nitrate concentration from 1 to 50 muM. The calculated detection limit for nitrate is 8 x 10(-7)M in pure aqueous solution. The method has been applied to determination of nitrate in fresh snow, and river waters and animal feeds.

Metaphysial dysostosis (Jansen type). Report of a case with long follow-up.

A case of the Jansen type of metaphysial dysostosis, followed for fifteen years from childhood to the age of nineteen, is reported. Radiographs taken at five years revealed the characteristic metaphysial changes in all the tubular bones, especially those of the hands and feet. The acetabular and glenoid areas, the costochondral junctions and the sternal ends of the clavicles were also involved. Radiographs taken at nineteen years, however, showed only marked deformities, which shows that the involvement of the metaphyses can regress by the end of growth. Biopsy of the lower end of radius at the age of twelve revealed changes in the growth plate or physis, especially in the zone of resting cartilage. This finding suggests that cellular function in this zone is disturbed by some unknown mechanism. Hence, the term physial dysostosis may be more accurate than metaphysial dysostosis.

Effects of Ca2+ and Mg2+ on dynamics of the polar head group of phosphatidylserine bilayers.

The effects of Ca2+ and Mg2+ on the molecular motion of the polar head group in phosphatidylserine (PS) bilayers were measured by the time-resolved fluorescence depolarization method probed by 1,2-dihexadecanoyl-sn-glycero-3-phospho-[N-(4-nitrobenzo- 2-oxa-1,3-diazole)]ethanolamine [formula: see text] (NBD-PE). By this method, the rate and width of the molecular motion at the fluorescent moieties in the probe molecules could be evaluated as the wobbling diffusion rate (Dw, s-1) and the half cone angle of the wobbling cone (theta c, degree). The values of Dw and theta c measured for NBD-PE embedded in bovine brain phosphatidylserine bilayers were 3.7 x 10(7) s-1 and 46 degrees in the absence of divalent cations at 25 degrees C. When 3 mM of Ca2+ was added, both Dw and theta c distinctly dropped to 1.7 x 10(7) s-1 and 38 degrees, respectively. By the addition of 3 mM of Mg2+, however, only Dw decreased to 2.7 x 10(7) s-1 and theta c remained unchanged. These results show that both Ca2+ and Mg2+ decrease the rate of motion at the head part in PS molecules, but only Ca2+ narrows the distance between the neighboring head groups. Since Mg2+ does not promote vesicle fusion, it appears that the deformation at the head group region in the bilayer structure induced by Ca2+ is an important step in the membrane fusion process.