Antimigraine drug interactions with 5‐hydroxytryptamine1A receptors

Abstract

The interactions of four antimigraine drugs with 5-hydroxytryptamine_1A and beta-adrenergic receptors were analyzed in rat brain membranes. Methysergide, cyprohepatadine, (−)propranolol, and pizotifen display similar affinities (IC₅₀ values, 83 to 280 nM) for 5-hydroxytryptamine_1A 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]dihydroal-prenolol (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-hydroxytryptamine_1A receptor is a common site of action for (−)propranolol and other antimigraine agents.