[Effect of age on the number and size of myelinated nervous fibers. A qualitative and quantitative study in the rat].
The number and the average diameter of the myelinated fibers have been recorded in the both medial gastrocnemius nerves in the rat. The study concerned foetus at the end of the intra-uterine life as well as old rats (24 months). It seemed the absolute necessity to collect these data before studying the consequences of age on nervous regeneration. Electron microscopy was used in very small samples, photonic microscopy in bigger ones. The first myelinated fibers appear during the first day of life. Their number becomes steady around 2 months of live. But their diameter changes and increases until the end of the 6th month. In pubescent animals, the global variations between the two sides are negligible (average right number 260 +/- 8 fibers, average left 258 +/- 12, average right diameter 1.7 +/- 0.7 microns, average left diameter 7.1 +/- 0.6 microns).
Lapierre
F
F
Neurochirurgie, CHRU La Miletrie, Poitiers.
Arbeille
B
B
Mira
J C
JC
D000375:Aging; D000818:Animals; D048429:Cell Size; D009186:Myelin Sheath / Q000502:physiology*; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009416:Nerve Regeneration; D051381:Rats; D017208:Rats, Wistar
Effet de l'âge sur le nombre et le calibre des fibres nerveuses myélinisées. Etude qualitative et quantitative chez le rat.