THE EFFECTS OF AGING ON CEREBELLAR BETA-ADRENERGIC-RECEPTOR ACTIVATION AND MOTOR LEARNING IN FEMALE F344 RATS

Female Fischer 344 (F344) rats were tested for age-related differences in both cerebellar beta-adrenergic receptor activation and motor lear ning. Three and 20 month old rats were tested on a motor learning para digm that required the rats to adjust their gait to navigate a runway of unevenly spaced pegs. Rates of acquisition were compared between ag e groups. After behavioral testing, cerebellar beta-adrenergic recepto r function was assessed using extracellular recordings of Purkinje cel ls during iontophoresis of GABA and isoproterenol (ISO). Aged female r ats showed deficits in motor learning and in beta-adrenergic receptor activation. In young rats, ISO modulated GABAergic inhibition of Purki nje cell firing in more cells compared with aged rats. Thus, aging pro duces deficits in both motor learning and in beta-adrenergic receptor activation in aged female F344 rats.