Relationship between behavioral and motor responses of mature and old mice and cerebellar beta-adrenergic receptor...

Aging alters motor performance. Changes in adrenergic systems also occur and may be involved in altered motor function. Since beta-adrenergic input is prominently involved in cerebellar control, the current study investigated the relationship between cerebellar beta-adrenergic status and motor function in old (27 month) and mature (10 month) C57BL mice. Plank balance, photocell box activity and novelty-induced locomotion were all greater in mature compared to old mice (P less than 0.01) as was beta-adrenergic receptor density. Beta-adrenergic receptor density, but not receptor affinity for antagonist, was highly correlated to these measures of motor function when results from both groups of animals were analyzed: Plank balance (R = 0.80, P less than 0.01); locomotion in an open field (R = 0.60, P less than 0.01) and in a photocell box (R = 0.59, P less than 0.02). Aging alters cerebellar motor function and part of this dysfunction is correlated with beta-adrenergic receptor density.