Different Regions Of Mouse Brain Research Articles

Development of a protocol for the automated analysis of amino acids in brain tissue samples and microdialysates

An automated precolumn derivatisation method has been developed for the measurement of fourteen amino acids in brain tissue and microdialysate samples. The method involves labelling amino acids with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide (CN −). The resulting highly stable N-substituted 1-cyanobenz[ f]isoindole (CBI) derivatives were separated using a binary gradient elution profile and detected fluorometrically. The order of elution of the derivatised amino acids was confirmed by using liquid chromatography with fluorescence and mass spectrometric detection in tandem. Linear calibration plots were obtained for all amino acids in the range studied (0.2–12.5 μ M). The limit of detection for CBI derivatives of amino acids was in the range 5–20 fmol ( S/N=2) using a 5 μl injection volume. The method has been used for the measurement of amino acids in microdialysates from rat brain and tissue homogenates from different regions of mouse brain.

ROLE OF METALLOTHIONEIN AND OTHER ANTIOXIDANTS IN SCAVENGING SUPEROXIDE RADICALS AND THEIR POSSIBLE ROLE IN NEUROPROTECTION

Based on the inhibition of nitrite formation by generating superoxide from xanthine/xanthine oxidase (X/XO) reaction system, metallothionein (MT) and other sulfhydryl containing amino acids have been selected to test their abilities to scavenge superoxide radicals. Different concentrations of metallothionein and other sulfhydryl containing molecules e.g. cysteine, N-acetyl-cysteine and glutathione, were used to assess superoxide scavenging properties. Metallothionein scavenges superoxide radical in a dose-dependent manner with increasing concentrations as evidenced by the inhibition of nitrite formation. Similar abilities to scavenge superoxide radicals were shown by cysteine, N-acetyl-cysteine. Glutathione also scavenges superoxide radical in a dose-dependent manner. In vitro experiments demonstrated that metallothionein is superior in scavenging superoxide radicals compared to other sulfhydryl molecules such as cysteine, N-acetyl-cysteine and even glutathione. The data, further, suggest that metallothionein-II has a 6-fold higher capacity to scavenge superoxide radical than metallothionein-I. In addition, metallothionein-like protein was isolated from different regions of mouse brain treated with zinc. Brain metallothionein-like protein inhibits nitrite formation as demonstrated by other scavengers; however, the extent of inhibition is different by this protein isolated from different brain regions. The present study suggests that metallothioneins and metallothionein-like proteins isolated from mouse brain act as neuroprotective agents by scavenging superoxide radicals. Published by Elsevier Science Ltd.

Age-related changes in antioxidant enzymes, superoxide dismutase, catalase, glutathione peroxidase and glutathione in different regions of mouse brain

It has been proposed that neurodegenerative processes of aging are associated with the generation of reactive oxygen species (ROS) during cellular metabolism. These reactive oxygen species are scavenged by antioxidant enzymes in biological systems. The present study was designed to determine the selective distribution of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase activity and reduced glutathione (GSH) levels in different regions of the C57BL/6N mouse brain and to determine if any alterations occurred with age. Catalase activity did not show any significant change except in cerebellum. Activity of superoxide dismutase was increased with age in all regions of the brain except in hippocampus of 2-yr-old mice. The glutathione peroxidase activity in the caudate nucleus increased in all regions of the brain, however, the activity did not change at one, six and 12 months. A significant increasing pattern of glutathione content was found in the cerebellum and brain stem with age. These data demonstrate that although the level of antioxidant enzymes varied in different regions of the brain, overall the enzyme activities tend to increase with age.

Modulation of choline transport and acetylcholine synthesis in synaptosomes from different brain regions.

Uptake and biotransformation of radioactive choline (3H-Ch) have been studied in P2 fractions from different brain regions of mice treated with different doses of sodium pentobarbital (45-120 mg/kg intraperitoneally) or saline. Sodium dependent uptake (SDU) has been measured as the difference between results of incubations with Na+ in the incubation medium and when the sodium salts were replaced by Trisphosphate and sucrose. The uptake of radioactivity increased during the incubation with 3H-Ch but the proportion of 3H-ACh was the same at all time points. The proportion of 3H-ACh to 3H-Ch in the P2 pellet was 86, 81 and 69 per cent in hippocampus, striatum and cortex, respectively. Omission of sodium ions in the incubation medium reduced uptake of 3H-Ch by about 90 per cent at 1 microM Ch in the incubation medium and the proportion of 3H-ACh to 3H-Ch was only 10 to 20 per cent while the proportion of 3H-PhCh increased from insignificant amounts to between 20 to 30 per cent. There were quantitative regional differences in SDU, a two times greater uptake was obtained in the striatum compared with cortex and hippocampus. Apparent Km and Vmax were 0.9 X 10(-6)M and 71 pmol/mg, respectively, for the cortex of untreated animals. The contribution of endogenous Ch from the P2 fraction to the incubation medium gave a final concentration of 0.5 microM Ch in the standard uptake experiments. The 3H-Ch uptake was significantly reduced in P2 fraction from cortex and hippocampus prepared from mice anaesthetized with sodium pentobarbital while the uptake in P2 fractions from the striatum was unaffected. Sodium pentobarbital treatment did not affect the proportion of 3H-ACh in the pellets.

Effects of reserpine on recovery rates after inhibition of monoamine oxidase in different regions of mouse brain

1. 1. Adult mice were injected once with the monoamine oxidase (MAO) inhibitor pargyline, every 3 days with the amine storage depletor reserpine, or with both drugs. 2. 2. Serotonin content of brainstem and cerebrum was increased after pargyline, decreased after reserpine, and showed intermediate values following administration of both drugs. 3. 3. MAO activity after pargyline recovered in a time-dependent fashion, with recovery rates of hypothalamus > cerebellum > cerebrum > brainstem. 4. 4. After reserpine, recovery rates of MAO were less in hypothalamus and cerebellum, suggesting that the amount of MAO synthesized may be related to the level of substrates in these regions.

Effects of lithium chloride on the cholinergic system in different brain regions in mice

Effects of lithium chloride on the cholinergic system in different brain regions in mice