demyelinate

tr.v., -at·ed, -at·ing, -ates.
To destroy or remove the myelin sheath of (a nerve fiber), as through disease.

demyelination de·my'e·lin·a'tion n.

(dēmī′-əlināt)
n

The process of removing or damaging the myelin sheath surrounding a nerve.

To destroy or remove the myelin sheath of a nerve or nerves.