5-Hydroxtryptamine1D receptor agonism predicts antimigraine efficacy

The interactions of four abortive anti-migraine agents and four prophylactic anti-migraine agents with 5-HT1D receptors in bovine brain were analyzed using radioligand binding techniques and adenylate cyclase assays. In bovine caudate, the affinities of abortive anti-migraine agents (i.e. 5-hydroxytryptamine, ergotamine, dihydroergotamine, sumatriptan) for 5-HT1D receptors range from 4.0-34 nM while the affinities of prophylactic anti-migraine agents (i.e. methysergide, amitriptyline, (-)propranolol, verapamil) range from 46-11,000 nM. In adenylate cyclase studies in bovine substantia nigra, all four abortive anti-migraine agents dose-dependently inhibit forskolin-stimulated adenylate cyclase activity, a biochemical effect mediated by 5-HT1D receptors. No agonist effect on cyclase activity is observed with the four prophylactic anti-migraine agents. These data support the hypothesis that abortive anti-migraine agents are 5-HT1D receptor agonists and that this effect may underlie their anti-migraine efficacy.