title: Changes with age in the number and size of myelinated axons in the rat L4 dorsal spinal root.
abstract: The number and size of myelinated axons in the L4 dorsal spinal root were determined in young rats and compared to those in the adult (older than 1 year) and in the old rats (older than 2 years). While the total number of myelinated axons was about the same at all ages, the average overall axon diameter showed a growth-related increase in adult animals, followed by a decrease reflecting senile atrophy in old rats. It is suggested that in aging laboratory rats the extent of axon shrinkage could account for the occurrence of secondary radicular demyelination.
mesh_terms: D000375:Aging; D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D008161:Lumbosacral Region; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure*; D051381:Rats / Q000502:physiology*; D011919:Rats, Inbred Strains; D013126:Spinal Nerve Roots / Q000648:ultrastructure*