EFFECTS OF THE SEROTONIN( 1B 1D) RECEPTOR AGONIST ZOLMITRIPTAN ON MOTOR CORTICAL EXCITABILITY IN HUMANS/

Oral administration of zolmitriptan, a novel 5-hydroxytriptamine recep tor agonist, to eight healthy volunteers significantly reduced motor c ortical excitability as tested by paired transcranial magnetic stimula tion (TMS) at short interstimulus intervals. Zolmitriptan did not chan ge motor thresholds to TRIS or electromyographic silent period duratio ns. We conclude that zolmitriptan acts centrally by reducing the inhib ition within the motor cortex. The results suggest that the action of zolmitriptan on motor cortical excitability does not result from chang es at the level of the cell membrane but from the influence on GABAerg ic inhibitory interneurons.