Maintenance of myelinated fibre g ratio in acute experimental allergic encephalomyelitis

John Guy, E. Ann Ellis, G. Marion Hope, Scott Emerson

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The spectra of myelin sheath thickness and g ratio (axon diameter/fibre diameter) of guinea pig optic nerves for 8 animals with acute experimental allergic encephalomyelitis (EAE) were compared with those for 6 normal animals. The mean myelin sheath thickness of 0.12 μm for the animals with EAE was significantly lower than the value of 0.16 μm for the normal animals. Since fibre diameter comprises axon diameter plus the thickness of its surrounding myelin sheath, a reduction in mean fibre diameter from 1.52 μm in normals to 1.20 μm in EAE was expected, but it was surprising to find that a mean g ratio of 0.85 obtained for normal nerves was not substantially different from a value of 0.86 for demyelinated optic nerves. A decrease in the mean axon diameter of 1.24 μm for normal animals to 0.94 μm for those with EAE tended to offset the decrease in mean myelin sheath thickness and contributed to the relative stability of the g ratio with acute demyelination. Our results showing reduction in axonal calibre and myelin sheath thickness may offer an explanation for apparent discrepancies between electrophysiological delays in conduction characteristics of experimental and, if not the result of a maturational effect on myelination, human primary demyelinating disorders associated with the scant histopathological demyelination of initial attacks of EAE and the visually asymptomatic patients with multiple sclerosis.

Original languageEnglish
Pages (from-to)281-294
Number of pages14
JournalBrain
Volume114
Issue number1 PART A
StatePublished - Feb 1 1991
Externally publishedYes

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Autoimmune Experimental Encephalomyelitis
Myelin Sheath
Maintenance
Demyelinating Diseases
Axons
Optic Nerve
Multiple Sclerosis
Guinea Pigs

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Guy, J., Ellis, E. A., Hope, G. M., & Emerson, S. (1991). Maintenance of myelinated fibre g ratio in acute experimental allergic encephalomyelitis. Brain, 114(1 PART A), 281-294.

Maintenance of myelinated fibre g ratio in acute experimental allergic encephalomyelitis. / Guy, John; Ellis, E. Ann; Hope, G. Marion; Emerson, Scott.

In: Brain, Vol. 114, No. 1 PART A, 01.02.1991, p. 281-294.

Research output: Contribution to journalArticle

Guy, J, Ellis, EA, Hope, GM & Emerson, S 1991, 'Maintenance of myelinated fibre g ratio in acute experimental allergic encephalomyelitis', Brain, vol. 114, no. 1 PART A, pp. 281-294.
Guy J, Ellis EA, Hope GM, Emerson S. Maintenance of myelinated fibre g ratio in acute experimental allergic encephalomyelitis. Brain. 1991 Feb 1;114(1 PART A):281-294.
Guy, John ; Ellis, E. Ann ; Hope, G. Marion ; Emerson, Scott. / Maintenance of myelinated fibre g ratio in acute experimental allergic encephalomyelitis. In: Brain. 1991 ; Vol. 114, No. 1 PART A. pp. 281-294.
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