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  • 1
    Digitale Medien
    Digitale Medien
    A critique on the preparation and enzymatic characterization of synaptic and nonsynaptic mitochondria from hippocampus (1989)
    Springer
    Cellular and molecular neurobiology 9 (1989), S. 247-262 
    Details
    ISSN: 1573-6830
    Schlagwort(e): hippocampus ; mitochondria ; enzymes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. In literature two interesting methods are described to obtain from whole pooled brains or areas three types of mitochondria, namely, those of perikaryal origin and those contained in synaptosomes. 2. However, for many types of studies, such “preparative” preparations are not useful; for example, in pharmacological studies only data from a singlen number of animals may be of statistical usefulness and may be correctly analyzed by statistical tests. 3. Thus a method is described by which it was possible to characterize by enzyme activities three populations from single rat brain hippocampus. 4. During preparative “analytical” procedure, it was noted that the 10% Ficoll gradients previously used in the literature were unable to separate purified mitochondria-free mitochondria. This gradient should be 12% Ficoll for single areas. 5. In addition, when results are compared using the more appropriateω 2 t for calculations of gravity forces to be applied instead of the maximum or averageg for different rotors, enzymatic characterization differed considerably among the various mitochondrial populations. 6. The above considerations are also true when different pestle clearances and/or pestle rotations speeds are used during omogenizations; also lysis conditions are essential. 7. Results showed that selected experimental conditions are to be used when subcellular fractions are to be analyzed biochemically.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00713032
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  • 2
    Digitale Medien
    Digitale Medien
    Changes of mitochondrial membrane proteins in rat cerebellum during aging (1988)
    Springer
    Neurochemical research 13 (1988), S. 859-865 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Mitochondrial membranes ; proteins ; cerebellum ; aging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Qualitative and quantitative changes of mitochondrial membrane proteind during aging were investigated. Free (non-synaptic) mitochondria were purified from rat cerebellum at different ages (4, 8, 12, 16, 20, and 24 months). Mitochondrial outer membrane (OM), inner membrane (IM) and matrix (MX) were separated and the proteins were extracted and analyzed by gel-electrophoresis. After staining, the gels were scanned densitometrically to quantify the proteins. No significant changes in the quantity of OM or MX protein subunits were observed, while serveral statistically significant quantitative changes in IM proteins with age were found. These age-dependent modifications of inner membrane mitochondrial proteins may play an important role in energy transduction, transport systems and regulatory enzymatic activities in mitochondria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00970754
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  • 3
    Digitale Medien
    Digitale Medien
    G protein dependent alterations in [125I] iodocyanopindolol and ±cyanopindolol binding at 5HT1B binding sites in rat brain membranes (1989)
    Springer
    Neurochemical research 14 (1989), S. 1245-1245 
    Details
    ISSN: 1573-6903
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00965517
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  • 4
    Digitale Medien
    Digitale Medien
    Changes of mitochondrial cytochrome c oxidase and FoF1 ATP synthase subunits in rat cerebral cortex during aging (1995)
    Springer
    Neurochemical research 20 (1995), S. 1465-1470 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Cytochrome c oxidase ; FoF1 ATP synthase ; aging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The contents of subunits I, II/III, and IV of cytochrome c oxidase and of subunits α, β and γ of FoF1 ATP synthase in inner mitochondrial membrane proteins purified from cerebral cortex of rat at 2, 6, 12, 18, 24, and 26 months of age were analyzed by western blot. Age-related changes in the content of subunits, either of mitochondrial or nuclear origin, were observed. All the cytochrome c oxidase (COX) subunits examined showed an age-related increase from 2-month-old rats up to 24 months with a decrease at the oldest age (26 months). The same pattern of age-dependent changes was observed for γ ATP synthase, while the α and β subunits increased progressively up to 26 months.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00970595
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  • 5
    Digitale Medien
    Digitale Medien
    Effect of In Vivo Administration of Naloxone on ATP-ase's Enzyme Systems of Synaptic Plasma Membranes from Rat Cerebral Cortex (2000)
    Springer
    Neurochemical research 25 (2000), S. 867-873 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Cerebral cortex ; ATP-ases ; synaptic plasma membranes ; naloxone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Naloxone is a specific competitive antagonist of morphine, acting on opiate receptors, located on neuronal membranes. The effects of in vivo administration of naloxone on energy-consuming non-mitochondrial ATP-ases were studied in two different types of synaptic plasma membranes from rat cerebral cortex, known to contain a high density of opiate receptors. The enzyme activities of Na+, K+-ATP-ase, Ca2+, Mg2+-ATP-ase and Mg2+-ATP-ase and of acetylcholinesterase (AChE) were evaluated on synaptic plasma membranes obtained from control and treated animals with effective dose of naloxone (12μg · kg−1 i.m. 30 minutes). In control (vehicle-treated) animals specific enzyme activities assayed on these two types of synaptic plasma membranes are different, being higher on synaptic plasma membranes of II type than of I type, because the first fraction is more enriched in synaptic plasma membranes. The acute treatment with naloxone produced a significant decrease in Ca2+,Mg2+-ATP-ase activity and an increase in AChE activity, only in synaptic plasma membranes of II type. The decrease of Ca2+,Mg2+-ATP-ase enzymatic activity and the increased AChE activity are related to the interference of the drug on Ca2+ homeostasis in synaptosoplasm, that leads to the activation of calcium-dependent processes, i.e. the extrusion of neurotransmitter. These findings give further evidence that pharmacodynamic characteristics of naloxone are also related to increase [Ca2+] i , interfering with enzyme systems (Ca2+,Mg2+-ATP-ase) and that this drug increases acetylcholine catabolism in synaptic plasma membranes of cerebral cortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1007529826905
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  • 6
    Digitale Medien
    Digitale Medien
    Energy Metabolism of Synaptosomal Subpopulations from Different Neuronal Systems of Rat Hippocampus: Effect of L-Acetylcarnitine Administration In Vivo (1999)
    Springer
    Neurochemical research 24 (1999), S. 617-624 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Synaptosomal subpopulations ; “large” and “small” synaptosomes ; energy metabolism ; enzymes ; L-acetylcarnitine treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The maximum rate (Vmax) of some enzyme activities related to glycolysis, Krebs' cycle, acetylcholine catabolism and amino acid metabolism were evaluated in different types of synaptosomes obtained from rat hippocampus. The enzyme characterization was performed on two synaptosomal populations defined as “large” and “small” synaptosomes, supposed to originate mainly from the granule cell glutamatergic mossy fiber endings and small cholinergic nerve endings mainly arising from septohippocampal fiber synapses, involved with cognitive processes. Thus, this is an unique model of pharmacological significance to study the selective action of drugs on energy metabolism of hippocampus and the sub-chronic i.p. treatement with L-acetylcarnitine at two different dose levels (30 and 60 mg · kg−1, 5 day a week, for 4 weeks) was performed. In control animals, the results indicate that these two hippocampal synaptosomal populations differ for the potential catalytic activities of enzymes of the main metabolic pathways related to energy metabolism. This energetic micro-heterogeneity may cause their different behaviour during both physiopathological events and pharmacological treatment, because of different sensitivity of neurons. Therefore, the micro-heterogeneity of brain synaptosomes must be considered when the effect of a pharmacological treatment is to be evaluated. In fact, the in vivo administration of L-acetylcarnitine affects some specific enzyme activities, suggesting a specific molecular trigger mode of action on citrate synthase (Krebs' cycle) and glutamate-pyruvate-transaminase (glutamate metabolism), but mainly of “small” synaptosomal populations, suggesting a specific synaptic trigger site of action. These observations on various types of hippocampal synaptosomes confirm their different metabolic machinery and their different sensitivity to pharmacological treatment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1021008306414
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  • 7
    Digitale Medien
    Digitale Medien
    Action ofl-acetylcarnitine on age-dependent modifications of mitochondrial membrane proteins from rat cerebellum (1988)
    Springer
    Neurochemical research 13 (1988), S. 909-916 
    Details
    ISSN: 1573-6903
    Schlagwort(e): l-Acetylcarnitine ; cerebellum ; mitochondrial membranes ; proteins ; aging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Protein patterns of mitochondrial outer membrane, inner membrane, and matrix from nonsynaptic (free) mitochondria from rat cerebellum at different ages (4, 8, 12, 16, 20, and 24 months) were analyzed by gel electrophoresis. Acutel-acetylcarnitine treatment was per-formed by a single i.p. injection (100 mg/kg body weight) of the substance 60 min before the sacrifice of the animals. Different age-dependent changes were obtained for the proteins of the three fractions. The amount of some protein subunits increased and/or decreased after drug treatment. In particular, protein composition of the inner mitochondrial membrane showed significant age-related modifications. This result probably indicates differences in protein synthesis and/or turnover rates in the various mitochondrial compartments during aging. Acutel-acetylcarnitine treatment caused: a high increase in the amount of one inner membrane protein with Mw 16 kDa, at all the ages studied; a decrease in the amount of many other inner membrane proteins; modifications of some matrix proteins. Our results show that in vivo administration ofl-acetylcarnitine affects mainly the inner membrane protein composition of cerebellar mitochondria.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00970761
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  • 8
    Digitale Medien
    Digitale Medien
    Changes induced by aging and drug treatment on cerebral enzymatic antioxidant system (1988)
    Springer
    Neurochemical research 13 (1988), S. 467-478 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Antioxidant enzymes ; aging ; peroxidation ; drug treatment
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The age-related modifications of the participants to the cerebral enzymatic antioxidant system (superoxide dismutase, glutathione peroxidase, glutathione reductase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase) were evaluated in four brain regions from male Wistar rats aged 5, 10, 15, 20, 25, 30, and 35 months. Both the specific enzyme activity and the profile of any enzyme tested markedly differ with age according to the region examined: parieto-temporal cortex, caudate-putamen, substantia nigra and thalamus. This inhomogeneous age-related profile of enzyme activities could explain both the controversial data of literature and the different regional vulnerability of the brain tissue to damage with aging. In rats aged 10, 20, or 30 months, the chronic i.p. treatment for two months with papaverine or ergot alkaloids (dihydroergocristine, dihydroergocornine, dehydroergocriptine) suggests that the antioxidant enzyme activities may be influenced according to the agent utilized, the brain region tested, and the age of the animal. In any case, small differences in the drug structure support marked differences in the type and extent of the intervention on the antioxidant enzymatic system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01268883
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  • 9
    Digitale Medien
    Digitale Medien
    Age-related effect induced by oxidative stress on the cerebral glutathione system (1989)
    Springer
    Neurochemical research 14 (1989), S. 473-481 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Brain aging ; glutathione system ; free radicals ; oxidative stress ; ergot alkaloids ; papverine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In the forebrain from male Wistar rats aged 5, 15 and 25 months, age-related putative alterations in the glutathione system (reduced and oxidized glutathione; redox index) were chronically induced by the administration in drinking water of free radical generators (hydrogen peroxide, ferrous chloride) or of inhibitors of endogenous free radical defenses (diethyl-dithio-carbamate, an inhibitor of superoxide dismutase activity). In hydrogen peroxide administered rats, both reduced glutathione and the cerebral glutathione redox index markedly declined as a function of aging, whereas oxidized glutathione consistently increased. In contrast, chronic iron intake failed to modify the reduced glutathione in forebrain from the rats of the different ages tested, whereas the oxidized glutathione was increased in the older brains. The chronic intake of diethyl-dithio-carbamate enhanced the concentrations of reduced glutathione in the forebrains from the rats of the different ages tested, the oxidized glutathione being unchanged. In 15-month-old rats submitted to chronic oxidative stress, ergot alkaloids (and particularly dihydroergocriptine) interfered with cerebral glutathione system, while papaverine was always ineffective. The comprehensive analysis of the data indicates that: (a) both the type of oxidative stress and the age of the animals modulate the cerebral responsiveness to the putative modifiers in the level of tissue free radicals; (b) aging magnifies the cerebral alterations induced by oxidative stress; the (c) cerebral glutathione system may be modified by metabolic rather than by circulatory interferences; (d) a balance between the various cerebral antioxidant defenses is present, the perturbation of an antioxidant system resulting in the compensatory modified activity of component(s) of another system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00964863
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  • 10
    Digitale Medien
    Digitale Medien
    Age-dependent changes of nucleic acid labeling in different rat brain regions (1989)
    Springer
    Neurochemical research 14 (1989), S. 701-706 
    Details
    ISSN: 1573-6903
    Schlagwort(e): Aging ; DNA ; ribosomal RNA ; poly(A)+ RNA ; CDP-choline
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The effects of aging on in vivo DNA and RNA labeling and on RNA content in various brain regions of 4-, 12-, and 24-month-old rats were investigated. No difference in [methyl-14C]thymidine incorporation into DNA of cerebral cortex and cerebelllum during aging was observed. The ratio of RNA/DNA content significantly decreased from 4 to 24 months of age in cerebral cortex, cerebellum and striatum. RNA labeling decreased by 15% in cerebral cortex of 24-month-old animals while in the other brain areas examined (cerebellum, hippocampus, hypothalamus, brainstem, striatum) did not change during aging. In the cerebral cortex, the ratio of the specific radioactivity of microsomal RNA to that of nuclear RNA, determined by in vivo experiments, was not affected by the aging process. A significant decrease of total, poly(A)+ RNA and poly(A)- RNA content was observed in the same brain area of 24-month-old rats compared to 4-month-old ones. Moreover, densitometric and radioactivity patterns obtained by gel electrophoresis of labeled RNA after in vitro experiments (tissue slices of cerebral cortex) showed a different ribosomal RNA processing during aging. In vivo chronic treatment with CDP-choline was able to increase RNA labeling in corpus striatum of 24-month-old animals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00964882
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