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  • 1
    Electronic Resource
    Electronic Resource
    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
    Keywords: hippocampus ; mitochondria ; enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00713032
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    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
    Keywords: Synaptosomal subpopulations ; “large” and “small” synaptosomes ; energy metabolism ; enzymes ; L-acetylcarnitine treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1021008306414
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Parkinson-like disease by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity inMacaca Fascicularis: Synaptosomal metabolism and action of dihydroergocriptine (1994)
    Springer
    Neurochemical research 19 (1994), S. 229-236 
    Details
    ISSN: 1573-6903
    Keywords: Parkinson-like syndrome by MPTP ; enzymes ; synaptosomes ; energy metabolism ; dihydroergocriptine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The maximal rates (Vmax) of some enzyme activities related to synaptosomal energy metabolism were studied in different types of synaptosomes from cerebellar cortex ofMacaca Fascicularis (Cynomolgus monkey). Different synaptosomal populations, namely “large” and “small” synaptosomes, were isolated from the anterior lobule of the cerebellar cortex of monkeys treated p.o. with dihydroergocriptine at the dose of 12 mg/kg/day before and during the induction of a Parkinson's-like syndrome by MPTP administration (i.v., 0.3 mg/kg/day for 5 days). The enzymes were chosen according to their regulatory role and as markers of the following metabolic pathways: (a) glycolysis ((hexokinase, phosphofructokinase, lactate dehydrogenase), (b) Krebs' (TCA) cycle (citrate synthase, malate dehydrogenase), (c) amino acid, glutamate metabolism (glutamate dehydrogenase, glutamate-pyruvate- and glutamate-oxaloacetate-transaminases), (d) acetylcholine catabolism (acetylcholinesterase) and (e) ATPases, i.e. Na+−K+-ATPase, Mg2+-ATP synthetase, Mg2+-ATPase, Ca2+−Mg2+-ATPase and Ca2+-ATPase Low and High affinity for Ca2+. The MPTP administration modified the activities of citrate synthase, malate dehydrogenase, Na+−K+-ATPase, acetylcholinesterase and glutamate-oxaloacetate transaminase only on selected types of synaptosomes. Pharmacological treatment by dihydroergocriptine was able to recovery at the steady-state levels the activities of these enzymes, thus demonstrating a partial protective effect on these biochemical parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00971569
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  • 4
    Electronic Resource
    Electronic Resource
    Action of L-Acetylcarnitine on Different Cerebral Mitochondrial Populations from Cerebral Cortex (1998)
    Springer
    Neurochemical research 23 (1998), S. 1485-1491 
    Details
    ISSN: 1573-6903
    Keywords: Cerebral cortex ; energy metabolism ; enzymes ; L-acetylcarnitine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The maximum rate (Vmax) of some mitochondrial enzymatic activities related to the energy transduction (citrate synthase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase, glutamate-pyruvate-transaminase, glutamate-oxaloacetate-transaminase) was evaluated in non-synaptic (free) and intra-synaptic mitochondria from rat brain cerebral cortex. Three types of mitochondria were isolated from rats subjected to i.p. treatment with L-acetylcarnitine at two different doses (30 and 60 mg·kg−1, 28 days, 5 days/week). In control (vehicle-treated) animals, enzyme activities are differently expressed in non-synaptic mitochondria respect to intra-synaptic “light” and “heavy” ones. In fact, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glutamate-pyruvate-transaminase and glutamate-oxaloacetate-transaminase are lower, while citrate synthase, cytochrome oxidase and glutamate dehydrogenase are higher in intra-synaptic mitochondria than in non-synaptic ones. This confirms that in various types of brain mitochondria a different metabolic machinery exists, due to their location in vivo. Treatment with L-acetylcarnitine decreased citrate synthase and glutamate dehydrogenase activities, while increased cytochrome oxidase and α-ketoglutarate dehydrogenase activities only in intra-synaptic mitochondria. Therefore in vivo administration of L-acetylcarnitine mainly affects some specific enzyme activities, suggesting a specific molecular trigger mode of action and only of the intra-synaptic mitochondria, suggesting a specific subcellular trigger site of action.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020907400905
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    Paper (German National Licenses)
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