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Carnitine (4-N-trimethylammonium-3-hydroxybutyric acid) seems to fulfill in the brain a different role than in peripheral tissues. Carnitine is accumulated by neural cells in a sodium-dependent way. The existence of a novel transporter in plasma membrane, specific to compounds with a polar group in the beta-position with respect to carboxyl group, has been(More)
Neurons are known to accumulate L-carnitine--a compound necessary for transfer of acyl moieties through biological membranes, apart from very low beta-oxidation of fatty acids in adult brain. Present study demonstrates expression of octn2 and octn3 genes coding high affinity carnitine transporters, as well as presence of both proteins in neurons obtained(More)
Carnitine beta-hydroxy-gamma-(trimethylammonio)butyrate - a compound necessary in the peripheral tissues for a transfer of fatty acids for their oxidation within the cell, accumulates in the brain despite low beta-oxidation in this organ. In order to enter the brain, carnitine has to cross the blood-brain barrier formed by capillary endothelial cells which(More)
Carnitine is known to accumulate in brain, therefore transport of carnitine through the blood-brain barrier was studied in an in vitro system using bovine brain capillary endothelial cells (BBCEC) grown on filter inserts in a co-culture system with glial cells. Long-term exposure of BBCEC to carnitine resulted in a high accumulation of long-chain acyl(More)
The accumulation of carnitine was measured in cerebral cortex neurons isolated from adult rat brain. This process was found to be lowered by 40% after preincubation with ouabain and with SH-group reagents (N-ethylmaleimide and mersalyl). The initial velocity of carnitine transport was found to be inhibited by 4-aminobutyrate (GABA) in a competitive way (Ki(More)
As reported previously [Acta Neurobiol. Exp. 57 (1997) 263], palmitoylcarnitine was observed to promote differentiation of neuroblastoma NB-2a cells with a concomitant inhibition of proliferation and of the phorbol ester stimulated activity of the protein kinase C (PKC). In the present study, palmitoylcarnitine was observed to inhibit phosphorylation of the(More)
[3H]Palmitic acid accumulates in neuroblastoma NB-2a cells, being incorporated in lipids (90%) and proteins (10%) fractions. Addition of palmitoylcarnitine, known to modulate activity of protein kinase C and to promote differentiation of neurons, was observed to decrease incorporation of palmitic acid to sphingomyelin, phosphatidylserine, and(More)
Palmitoylcarnitine is synthesized through the action of palmitoylcarnitine transferase I--an enzyme specifically inhibited by etomoxir. An increase of the intracellular content of palmitoylcarnitine in neuroblastoma NB-2a cells after administration of carnitine was correlated with an inhibition of cell proliferation and a concomitant promotion of(More)
Palmitoylcarnitine was observed previously to promote differentiation of neuroblastoma NB-2a cells, and to affect protein kinase C (PKC). Palmitoylcarnitine was also observed to increase palmitoylation of several proteins, including a PKC substrate, whose expression augments during differentiation of neural cells—a growth associated protein GAP-43, known to(More)
Transport of alpha-ketoisocaproic acid (KIC), the product of leucine transamination, was studied in the cerebral cortex cells isolated from the adult rat brain. The process of [(14)C]KIC accumulation was followed in the presence of aminooxyacetate, an inhibitor of transaminases. Accumulation of KIC was not affected by Na(+) replacement, its initial velocity(More)