<prompt> A teenager has seen her local physician complaining of persistent and severe headaches. Her physician diagnosed migraine and prescribes sumatriptan, which acts by which of the following mechanisms?Dopamine 1 agonistGABAB antagonistMuscarinic 3 antagonistSerotonin 1D agonist  <response>: Sumatriptan is a serotonin 1D agonist that is used to abo migraine headaches. It is also effective in the treatment of cluster headaches. Currently, no dopamine 1 D1 agonists, GABAB antagonists, or muscarinic m3 M3 antagonists are used clinically. 