THE SYSTEMIC ADMINISTRATION OF TACRINE OR SELEGILINE FACILITATE SPATIAL-LEARNING IN AGED FISHER-344 RATS

When compared to young Fisher 344 rats, aged Fisher 344 rats were impa ired in their acquisition of the water maze task as indicated by longe r escape latencies and distances to find a hidden platform. In a free swim trial which was performed after the training period, young rats h ad a better spatial bias: since they spent more time swimming ill the previous training quadrant. Tacrine 3 mg/kg, an anticholinesterase, an d selegiline 0.25 mg/kg, a MAO-B inhibitor, partially reversed the acq uisition deficit in aged rats when administered on their own, and drug -treated aged rats swam more in the previous training quadrant than ve hicle-treated aged rats during the fi-ee swim trial. Aged rats also sw am slower than young rats. Tacrine, but not selegiline, increased swim ming speed in aged rats. Taken as a whole, these data support the prop osal that tacrine may be effective at alleviating age-related learning impairment and confirm the role of cholinergic dysfunction in the spa tial learning deficit in aged rats.