Antimigraine drug interactions with 5-hydroxytryptamine1A receptors

The interactions of four antimigraine drugs with 5-hydroxytryptamine1A and beta-adrenergic receptors were analyzed in rat brain membranes. Methysergide, cyproheptadine, (-)propranolol, and pizotifen display similar affinities (IC50 values, 83 to 280 nM) for 5-hydroxytryptamine1A receptors labeled by [3H]8-hydroxy-N,N-dipropyl-2-aminotetralin. Cyproheptadine, pizotifen, and methysergide are essentially inactive at beta-adrenergic receptors labeled by [3H]dihydroalprenolol (IC50 values, 8,700 to 87,000 nM). By contrast, (-)propranolol is an extremely potent beta-adrenergic agent (IC50, 3 nM). These data indicate that the 5-hydroxytryptamine1A receptor is a common site of action for (-)propranolol and other antimigraine agents.