Amelioration of recognition memory impairment associated with iron loading or aging by the type 4-specific phosphodiesterase inhibitor rolipram in rats

Increasing evidence indicates that iron deposition in the brain might play a role in cognitive dysfunction associated with neurodegenerative disorders and aging. Previous studies have not examined whether iron-induced memory deficits can be attenuated by acute treatments with memory-enhancing agents. Phosphodiesterase type 4 (PDE4) inhibitors such as rolipram (ROL) ameliorate memory impairments in several rodent models of amnesia and have been proposed as candidate cognitive-enhancing drugs. Here we show that a single posttraining systemic injection of ROL dose-dependently attenuates the impairment of memory for novel object recognition (NOR) in rats given neonatal iron loading, a model of iron-induced cognitive impairment. Posttraining administration of ROL also recovered NOR deficits associated with aging in rats. These findings provide the first evidence that stimulation of an intracellular second messenger signaling pathway can attenuate iron-induced memory impairment, and support the view that PDE4 inhibitors might ameliorate cognitive dysfunction associated with aging and neurodegenerative disorders.