INCREASED DENDRITIC EXTENT IN HIPPOCAMPAL CA1 NEURONS FROM AGED F344 RATS

Citation
Gk. Pyapali et Da. Turner, INCREASED DENDRITIC EXTENT IN HIPPOCAMPAL CA1 NEURONS FROM AGED F344 RATS, Neurobiology of aging, 17(4), 1996, pp. 601-611
Citations number
47
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
01974580
Volume
17
Issue
4
Year of publication
1996
Pages
601 - 611
Database
ISI
SICI code
0197-4580(1996)17:4<601:IDEIHC>2.0.ZU;2-X
Abstract
Age-related dendritic alterations were evaluated in F344 rats followin g a water maze assessment of spatial memory. Based on the probe trial times, 39% of the aged animals were designated impaired. CAI pyramidal neurons were labeled intracellularly with neurobiotin in brain slices prepared from these animals. Neurons (aged: n = 15; young: n = ii) we re reconstructed using a microscope-based three-dimensional system. In creased dendritic length was observed in the aged neurons both for bas al dendrites (aged = 4.54 mm and young = 3.33 mm) and the entire neuro ns (aged = 14.8 mm and young = 10.8 mm). However, dendritic length val ues did not correlate with the individual animal's probe trial time. S hell analysis revealed a diffuse increase in dendritic branch intersec tions in the cells from aged rats, which on branch order analysis was noted to be due to an increased number of distal branches. Mean electr otonic distance to dendritic terminals, a functional assessment of syn aptic efficacy, was longer in the aged neurons (aged = 0.67 lambda and young = 0.55 lambda). These results suggest a lengthening and increas ed complexity of CA1 pyramidal neurons with successful aging, which ma y represent either an intrinsic response to aging or a reactive partia l denervation response to a loss of afferent inputs.