Age-related changes in basal dendrite and dendritic spine of hippocampal pyramidal neurons (CA1) among...

It has been confirmed that a substrain of the senescence-accelerated mouse SAMP1TA/Ngs develops learning disturbance-like behavior at 3 months of age, exhibits almost normal behavior at 5 months, and manifests learning disturbance at 7 months. The changes with age in basal dendrites and dendritic spines of CA1 pyramidal neurons were quantitatively evaluated by the Golgi method using male SAMP1TA/Ngs. The correlation between the change in learning ability and the morphometry was examined. The number of dendritic spines in the 3- and 7-month-old groups was significantly lower than that in the 5-month-old group. It is presumed that the disturbance in acquisition of learning ability at 3 months of age is secondary to the immaturity of neurons, while the learning disturbance at 7 months of age is due to neuronal aging. This substrain, which is characterized by the impairment of acquired learning ability due to senescence, is useful as a model for studies on human brain dysfunction associated with senescence.