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Nature. 2016 Jan 28;529(7587):523-7. doi: 10.1038/nature16519. Epub 2016 Jan 13.

Proton-gated Ca(2+)-permeable TRP channels damage myelin in conditions mimicking ischaemia.

Author information

1
Department of Neuroscience, Physiology &Pharmacology, University College London, Gower St., London WC1E 6BT, UK.

Abstract

The myelin sheaths wrapped around axons by oligodendrocytes are crucial for brain function. In ischaemia myelin is damaged in a Ca(2+)-dependent manner, abolishing action potential propagation. This has been attributed to glutamate release activating Ca(2+)-permeable N-methyl-D-aspartate (NMDA) receptors. Surprisingly, we now show that NMDA does not raise the intracellular Ca(2+) concentration ([Ca(2+)]i) in mature oligodendrocytes and that, although ischaemia evokes a glutamate-triggered membrane current, this is generated by a rise of extracellular [K(+)] and decrease of membrane K(+) conductance. Nevertheless, ischaemia raises oligodendrocyte [Ca(2+)]i, [Mg(2+)]i and [H(+)]i, and buffering intracellular pH reduces the [Ca(2+)]i and [Mg(2+)]i increases, showing that these are evoked by the rise of [H(+)]i. The H(+)-gated [Ca(2+)]i elevation is mediated by channels with characteristics of TRPA1, being inhibited by ruthenium red, isopentenyl pyrophosphate, HC-030031, A967079 or TRPA1 knockout. TRPA1 block reduces myelin damage in ischaemia. These data suggest that TRPA1-containing ion channels could be a therapeutic target in white matter ischaemia.

PMID:
26760212
PMCID:
PMC4733665
DOI:
10.1038/nature16519
[Indexed for MEDLINE]
Free PMC Article

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