question: Q:A 24-year-old woman in graduate school comes to the physician for recurrent headaches. The headaches are unilateral, throbbing, and usually preceded by blurring of vision. The symptoms last between 12 and 48 hours and are only relieved by lying down in a dark room. She has approximately two headaches per month and has missed several days of class because of the symptoms. Physical examination is unremarkable. The patient is prescribed an abortive therapy that acts by inducing cerebral vasoconstriction. Which of the following is the most likely mechanism of action of this drug?? 
  {'A': 'Inhibition of β1- and β2-adrenergic receptors', 'B': 'Activation of 5-HT1 receptors', 'C': 'Inhibition of 5-HT and NE reuptake', 'D': 'Inhibition of voltage-dependent Na+ channels', 'E': 'Inactivation of GABA degradation'},