Effects of apomorphine on flexor reflex and periodic limb movement.
It has been suggested that periodic leg movements (PLM) and spinal flexor reflex (FR) share common mechanisms. Although dopaminergic agents improve PLM in humans and strongly influence spinal FR circuitry in animal studies, its effects on FR have not been documented in humans. We describe a 65-year-old man with PLM after overnight withdrawal of dopaminergic agents. The electromyographic pattern of spontaneous PLM closely resembled that of the FR elicited by medial plantar nerve stimulation. Thirty minutes after subcutaneous injection of apomorphine, both PLM and FR were completely abolished. These findings demonstrate that dopaminergic agents can suppress exaggerated FR in humans, and support the hypothesis of common mechanisms for PLM and FR.
Division of Neurology, Toronto Western Hospital and The Toronto Western Research Institute, University Health Network, University of Toronto, Toronoto, Ontario, Canada.
Guillermo
G
Paradiso
Farooq
F
Khan
Robert
R
Chen
D000368:Aged; D001058:Apomorphine / Q000008:administration & dosage / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D004576:Electromyography; D006801:Humans; D007279:Injections, Subcutaneous; D008297:Male; D020189:Nocturnal Myoclonus Syndrome / Q000188:drug therapy* / Q000503:physiopathology; D012018:Reflex / Q000187:drug effects*; D013116:Spinal Cord / Q000503:physiopathology*
D018491:Dopamine Agonists; D001058:Apomorphine