Akathisia, motility, and locomotion in healthy volunteers.

Apomorphine (10 micrograms/kg subcutaneously with oral domperidone 10 mg), oral sultopride (50 mg), and placebos were given to nine normal volunteers, using a Latin-square design and double-blind procedures. A battery of tests was applied before the dose, and after the dose after time lapses of 15, 45, 90, 105, 120, and 180 min. Spatiotemporal and dynamic gait parameters, gait stability, and modulations remained unchanged with all three treatments. Apomorphine induced repeated yawning in all subjects. Akathisia was observed in four of nine subjects with sultopride. Sultopride was associated with drowsiness and sleepiness on visual analog scales. Akathisia may be related to decreased dopaminergic activity in the prefrontal cortex and mesocortical dopamine system blockade. The imbalance between mesocortical and nigrostriatal dopaminergic systems might explain the fact that sultopride in our experiment modified spontaneous behavior but not volitional behavior. Thus, it is possible to discriminate between two types of increased motor activity, and motility must be distinguished from locomotor activity.