Synaptosomes
Mostrando 13-24 de 155 artigos, teses e dissertações.
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13. Neurotransmitter-Specific Synaptosomes in Rat Corpus Striatum: Morphological Variations*
This communication describes ultrastructural variations among synaptosomal fractions isolated from the corpus striatum of the rat by incomplete equilibrium sedimentation in sucrose density gradients, and attempts to relate the variations to neurotransmitter-specific synaptosomes. The concentration of synaptosomes in each fraction of the density gradient was
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14. Myoinositol and phosphatidylinositol metabolism in synaptosomes from galactose-fed rats.
The effects of experimental galactose toxicity on inositol and phosphatidylinositol (PtdIns) metabolism in synaptosomes from 0- to 30-day-old rats were investigated. Galactose toxicity was induced by feeding mothers a 40% galactose diet from the 12th day of pregnancy until 19 days postpartum when the offspring were weaned onto the maternal diet. There was no
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15. Muscle-Like Contractile Proteins and Tubulin in Synaptosomes
Material in major bands with molecular weights corresponding to those of actin, brain tropomyosin, and myosin is present in purified rat synaptosomes dissolved in sodium dodecyl sulfate and subjected to electrophoresis on dodecyl sulfate-acrylamide gels. A band corresponding to tubulin appears to be the major constituent of synaptosomes, confirming the work
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16. The regulation of cytosolic calcium in rat brain synaptosomes by sodium-dependent calcium efflux.
1. When pinched-off presynaptic nerve endings (synaptosomes) isolated from rat brain are incubated in a low-Na (24-36 mM) medium, they take up 45Ca in a time-dependent manner. In a medium containing 1 mM-Ca, this Na-dependent 45Ca uptake amounts to approximately 10 nmol/mg protein at 1 min, and to approximately 40 nmol/mg protein at 20 min. The Na-dependent
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17. Relationship between presynaptic membrane potential and acetylcholine release in synaptosomes from Torpedo electric organ.
The membrane potential of purely cholinergic synaptosomes isolated from Torpedo electric organ was monitored with fluorescent carbocyanine dyes. An increased fluorescence was associated with depolarization and a quenching with hyperpolarization. Fluorescence data provided evidence that Torpedo synaptosomes have a membrane potential mainly driven by a K+ diff
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18. Evidence that parathyroid hormone-mediated calcium transport in rat brain synaptosomes is independent of cyclic adenosine monophosphate.
In vivo PTH administration to rats resulted in increased brain synaptosomal Ca++ transport, while parathyroidectomy (PTX) resulted in decreased transport. To determine the mechanism of action of PTH on Ca++ transport in rat brain synaptosomes, we performed transport studies by the Na-Ca exchanger and also measured cAMP generation in synaptosomes from PTX rat
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19. Characterization of dihydropyridine-sensitive calcium channels in rat brain synaptosomes.
We examined the effects of dihydropyridine Ca2+-channel agonists on synaptosomal voltage-dependent Ca2+ entry and endogenous dopamine release. The (-) isomer of Bay K 8644 and the (+) isomer of Sandoz compound 202-791 were 100-1000 times more potent than their respective opposite enantiomers in enhancing Ca2+ uptake and dopamine release from striatal synapto
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20. Phosphorylation of specific, distinct proteins in synaptosomes and axons from squid nervous system
Synaptosomes and axons from squid were incubated with [γ-32P]ATP or [32P]orthophosphate and specific, distinct proteins were found to be labeled in each preparation. In axoplasm, only the major 200,000 Mr neurofilament protein and a specific protein of ≈400,000 Mr were labeled, as reported previously [Pant, H. C., Shecket, G., Gainer, H. & Lasek, R. J. (1
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21. Bidirectional control of phospholipase A2 activity by Ca2+/calmodulin-dependent protein kinase II, cAMP-dependent protein kinase, and casein kinase II.
In preparations of synaptic terminals (synaptosomes) isolated from rat brain, the activity of phospholipase A2 (PLA2), a phospholipid hydrolase that serves a central function in signal transduction, was inhibited in a Ca(2+)-dependent manner by incubation with 60 mM K+ or with the Ca(2+)-selective ionophore ionomycin. Reversal by alkaline phosphatase treatme
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22. Calcium transport abnormality in uremic rat brain synaptosomes.
Brain calcium is elevated in patients and laboratory animals with uremia. The significance of this finding is unclear. We evaluated calcium transport in brain of both normal and acutely uremic rats (blood urea nitrogen = 250 mg/dl) by performing studies in synaptosomes from rat brain cerebral cortex. Synaptosomes are vesicular presynaptic nerve endings from
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23. Associative learning potentiates protein kinase C activation in synaptosomes of the rabbit hippocampus.
Using electrophysiological, biochemical, and autoradiographic techniques, changes in protein kinase C (PKC) activity in specific regions of the hippocampus have been previously implicated in classical conditioning of the nictitating membrane response of the rabbit. Here we report that activation of PKC is potentiated 2- to 3-fold in synaptosomes of the hippo
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24. Depolarization-induced changes in cellular energy production.
Addition of high concentrations of KC1 to preparations of rat brain synaptosomes incubated with either glucose or pyruvate caused a transient stimulation of oxygen uptake. This increased respiration was insensitive to 1 mM ouabain and 10 microM ruthenium red but was dependent upon the presence of calcium. With 40 mM KCl in the incubation medium, the levels o