Excitatory amino acid receptors in the prefrontal cortex of aging mice

The zones of the prefrontal cortex of Balb/c mice were tested for age-related changes of the ionotropic excitatory amino acid receptors density, together with zones of the dorsal cortex. Kainate, N-methyl-image-aspartate, and amino-3-hydroxy-5-methyloxazole-4-propionate sites were measured by slice receptor binding techniques in cortical zones from animals at the age of 6, 12, 18, and 24 months. An increase of the N-methyl-image-aspartate sites was detected in the medial prefrontal zone of mid-aged animals and was followed by a decrease at old age; a decrease of the N-methyl-image-aspartate and kainate sites was found for the medial dorsal (cingulate) cortex at old age. The age-related changes of receptor densities in the different cortical areas seem unrelated in origin. The sites decrease in the cingulate cortex could affect the transfer of the prefrontal cortex activity toward limbic structures.