Enhanced responsiveness of alpha-noradrenergic receptors following discrete electrolytic lesions of the nucleus locus coeruleus: a behavioral demonstration.

Locomotor activity was evaluated in groups of reserpine-treated mice administered the catecholamine receptor agonists apomorphine and clonidine. Pretreatment of selected groups of mice with discrete electrolytic destruction of the nucleus locus coeruleus (LC) resulted in a clonidine-potentiation of apomorphine-stimulated locomotor activity. This effect was greater in unilateral than bilateral lesioned mice. LC lesions also significantly reduced the level of locomotor habituation achieved within a 60 min observation period. The data are interpreted to suggest that discrete lesions of the nucleus LC results in increased alpha-noradrenergic receptor sensitivity.