Central demyelination induced in vivo by the calcium ionophore ionomycin.
The effects of injecting the calcium-selective ionophore, ionomycin, into myelinated tracts in the dorsal columns of adult rat spinal cords were examined electron microscopically. In vivo, ionomycin induced a primary vesicular demyelination, together with a variable degree of axonal degeneration, in a dose-dependent manner. The results are consistent with previous demonstrations that mature oligodendrocytes are more vulnerable to alterations in levels of [Ca2+]i than other glial cells. We speculate that demyelination induced by ionomycin in vivo occurs as a result of direct activation of endogenous Ca(2+)-dependent enzymes and/or as a consequence of oligodendrocyte injury mediated via astrocytes.
Smith
K J
KJ
Division of Anatomy and Cell Biology, United Medical School, London, UK.
Hall
S M
SM
D000818:Animals; D002118:Calcium / Q000502:physiology; D015759:Ionomycin / Q000494:pharmacology*; D008297:Male; D009186:Myelin Sheath / Q000187:drug effects* / Q000473:pathology* / Q000502:physiology; D009836:Oligodendroglia / Q000502:physiology / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000187:drug effects / Q000473:pathology*
D015759:Ionomycin; D002118:Calcium