Most species, including humans and fruit flies, exhibit age-related memory impairment. Various causes have been proposed, many of which converge on a mechanism involving cumulative oxidative damage. This hypothesis remains controversial, however. Yamazaki and colleagues now show that in Drosophila melanogaster, age-related memory impairment results from reduced NMDA receptor activation caused by age-related alterations in glial activity, and decreased D-serine production. Crucially, this mechanism is independent of oxidative damage. D-serine feeding suppresses both age-related memory impairment and memory impairment caused by glial overexpression of pyruvate carboxylase, indicating an oxidative stress-independent dysregulation. Overall, these data suggest that age-related memory impairment in Drosophila is caused by reduced NMDA receptor activity rather than oxidative damage.
Yamazaki D et al: Glial dysfunction causes age-related memory impairment in Drosophila. Neuron 84(4): 753-763 (2014).