Better than normal: improved formation of long-term spatial memory in healthy rats treated with levodopa

Abstract

Dopaminergic signaling modulates learning and memory. Consequently, treatment with the dopamine precursor levodopa ameliorates memory deficits in murine models of Alzheimer's disease. In healthy humans, administration of L-DOPA increases learning and memory. However, it is unknown whether dopamine-enhanced memory can also be modeled in normal animals. We here investigated if in healthy non-food-deprived rats low and high doses of levodopa (20 and 50 mg levodopa/kg bodyweight) increase spatial learning and long-term memory performance in a radial arm maze. After 4 months, rats treated with levodopa during training had significantly better memory of food rewarded arms than vehicle-treated animals. Interestingly, acute learning curves did not differ between levodopa and vehicle animals. This suggests that enhanced dopaminergic signaling may have predominantly acted on the cortical long-term consolidation of newly acquired spatial information.