Oxidative Stress and the CNS

What about the transporters?


Dr. Rice: In response to the question by Dr. Juurlink - I did not understand that the cellular concentration of ascorbate was determined mainly by its ability to reduce DHA to ascorbate.  I had always thought the number of ascorbate transporters was the key determinant.

On Mon Dec 14, Bernhard H.J. Juurlink wrote
>Dr, Rice,
>     One thing that puzzles me is why neurons which have a poor ability to reduce oxidized-ascorbate (because of their relatively oxidized cytosol) should have an order of magnitude more ascorbate than astrocytes which have a very good ability to reduce oxidized-ascorbate. Is there any evidence for ascorbate metabolic coupling between neurons and astrocytes with oxidized-ascorbate transferred from neurons to astrocytes and reduced-ascorbate transferred from astrocytes to neuron?  It is known that the glucose transporters transport oxidized-ascorbate and there would be a concentration gradient differential tending to move oxidized-ascorbate out of the neuron to the extracellular space and from there to the astrocyte.  What about the movement of reduced-ascorbate in the other direction?

>Why should there be so much ascorbate in neurons?  Does it have a function other than reducing oxidized-tocopherol?  What would this be?  BJ

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