What does demyelinate mean?
To demyelinate is to destroy or remove myelin, the fatty insulating sheath that wraps around nerve fibers and enables electrical impulses to travel quickly and efficiently along them. The word is used almost entirely within medicine and neuroscience: diseases such as multiple sclerosis are described as demyelinating precisely because they strip this protective layer from axons, slowing or blocking nerve conduction and producing symptoms ranging from numbness to paralysis. Demyelinate functions chiefly as a transitive verb — an autoimmune attack may demyelinate the optic nerves — though it can appear intransitively, as when damaged nerves simply begin to demyelinate over time. Derived forms include demyelination (the noun for the process itself), demyelinated (describing tissue already affected), and demyelinating (as in demyelinating disease). Because it carries strong clinical connotations, the word suits formal, technical writing rather than everyday conversation, where plain descriptions of nerve damage are more natural.
verbTo destroy or remove the myelin sheath surrounding nerve fibers, thereby impairing the transmission of nerve impulses.
- (of a disease process, injury, or agent) To destroy or strip away the myelin sheath encasing an axon, impairing or blocking nerve conduction.
"The autoimmune attack caused the immune system to demyelinate large tracts of the spinal cord."
"In multiple sclerosis, aberrant immune cells demyelinate axons throughout the central nervous system."
"The toxin was shown to selectively demyelinate peripheral nerves in laboratory animals."
When nerves lose their myelin — when they are demyelinated — signals slow down or stop entirely, which is exactly what happens in multiple sclerosis.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of demyelinate
Demyelinate combines the privative prefix de- (indicating removal) with myelin, the name of the fatty substance forming the insulating sheath around nerve fibers. Myelin derives from Greek myelos, meaning marrow or spinal cord, reflecting nineteenth-century anatomists' observation of the marrow-like appearance of white nervous tissue. The verb arose in twentieth-century medical literature alongside the noun demyelination as researchers characterized diseases that strip this sheath away.
Related word forms
How demyelinate is actually used
"Demyelinate" belongs almost exclusively to medical and scientific registers; lay speakers more often refer to "loss of myelin" or "demyelination" (the noun). It is typically used transitively, with the pathological agent as subject and nerve fibers as object, but also occurs intransitively in phrases such as "nerves begin to demyelinate."
Easily confused with demyelinate
To myelinate is to form or coat with a myelin sheath, while to demyelinate is the reverse — to strip that protective coating away.
Remineralize refers to restoring minerals, especially in tooth enamel or bone, and has nothing to do with nervous tissue.