A review of age-related changes in cerebellar beta-adrenergic function andassociated motor learning

The present review provides an overview of age-related changes in cerebella r beta-adrenergic function, associated motor learning, causal agents and po ssible treatments. Norepinephrine acts as a neuromodulator of Purkinje cell activity. With aging, however, the ability of norepinephrine to modulate P urkinje cell activity and specifically GABAergic inhibition of Purkinje cel l activity is decreased, This age-associated deficit in cerebellar noradren ergic function correlates with deficits in acquisition of a motor learning task. Aged rats are delayed in acquiring a motor learning task that require s rats to adjust footfalls in order to cross a runway. The degree of defici t in cerebellar beta-adrenergic activity correlated positively with the deg ree of impairment in task acquisition, One possible causal agent for the be ta-adrenergic deficit is free radical damage. Hyperoxia, which may generate free radical damage, induces cerebellar beta-adrenergic deficits in young rats but diet restriction and treatment with antioxidants can delay or reve rse age-related deficits in cerebellar beta-adrenergic function in old rats .