Adverse effects of catecholaminergic drugs following unilateral cerebellar ablations.

The following experiment was designed to examine the effects of unilateral cerebellar cortex lesions and pharmacological postinjury treatments with catecholamine drugs on recovery of beam walking ability in rats. Rats trained on a beam walking task were initially given either amphetamine, haloperidol, or a combination of the drugs at 24 h after injury, and tested at various intervals after drug administration. Six total doses were given to animals at 5d intervals during recovery. All drugs retarded recovery of function on the beam walking task compared to saline controls. Animals with cortical lesions that involved the deep cerebellar nuclei showed no recovery on the beam, regardless of group assignment. Phenoxybenzamine and propranalol were both ineffective in reinstating the beam walking deficit in those animals that demonstrated recovery on the beam walking task. The results indicate that the cerebellum plays a particularly important role in recovery of beam walking ability, and may contribute to beam walking recovery commonly observed after sensorimotor cortex ablations.