To investigate the effects of Ropinirole on the spinal flexor reflex in patients with restless legs syndrome and in healthy volunteers.

Trial description: D2 dopaminergic receptors may be involved in abnormal spinal reflex activity underlying Restless Legs Syndrome (RLS). To investigate this hypothesis the effects of ropinirole on the excitability of the spinal flexor reflex (FR) were evaluated, as well as the differences in endogenous D2 –activity in RLS subjects compared with normal controls. In addition ropinirole also has D3 and D4 agonist activity. To evaluate the degree to which non D2 agonist activity contributes to modulation of FR control and RLS manifestation, the study also examined the effects of a single dose of metoclopramide (a selective D2 antagonist) on the pharmacodynamic actions of ropinirole.