AGE-RELATED SYNAPTIC CHANGES IN THE CA1 STRATUM RADIATUM AND SPATIAL LEARNING IMPAIRMENT IN RATS

P>Age-related impairments in hippocampus-dependent spatial learning and memory are not associated with a loss of neurons, but may be related to synaptic changes. In the present study, we analysed the behavioural performance of adult, middle-aged and old Wistar rats using the Morris water maze, as well as the structure of synapses and the expression of autophosphorylated Ca2+/calmodulin-dependent protein kinase II at threonine 286 (pThr286-alpha CaMKII), a key post-synaptic protein in the CA1 stratum radiatum, in the same rats. Old Wistar rats showed significant cognitive deficits. Synaptic density, the area of post-synaptic densities and the total number of synapses in the CA1 stratum radiatum of old rats were significantly decreased compared with adult rats. The decrease in autophosphorylated pThr286-alpha CaMKII was age dependent. These findings reveal that age-related impairments in learning and memory are associated with synaptic atrophy. The decreased expression of pThr286-CaMKII may result in reduced synaptic function with ageing.