title: Age-related changes in soma size of neurons in the spinal cord motor column of the cat.
abstract: The present study was undertaken to examine the effect of the aging process on the soma size and number of motoneurons and interneurons in the motor column of the spinal cord of old cats. Neurons in the motor column were divided into small and large populations based on a bimodal distribution of their soma cross-sectional areas. A 17% decrease in the cross-sectional area of small neurons was observed, this decrease was statistically significant (P < 0.0001). The cross-sectional area of large neurons decreased by only 6%, which was statistically significant (P < 0.05). On the other hand, there was no significant difference in the number of large, small or of these combined population of ventral horn neurons in the aged cats compared with the control animals. This data suggest that neurons in the motor column are not uniformly affected by the aging process because morphological changes are proportionally greater in small neurons than in large neurons.
authors.affiliation: Department of Physiology, UCLA School of Medicine 90024, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Bertolotto
authors.forename: J K
authors.initials: JK
authors.lastname: Engelhardt
authors.forename: M H
authors.initials: MH
authors.lastname: Chase
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D002415:Cats; D002452:Cell Count; D007395:Interneurons / Q000502:physiology*; D009046:Motor Neurons / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology* / Q000648:ultrastructure