HTR1A and migraine disorder: It has been shown to have partial agonistic activity against 5-HT1A receptors and antagonistic activity against the 5-HT2A, 5-HT2B, 5-HT2C, and 5-HT7 receptors.[38,44] We believe that yokukansan itself, or the crude uncaria hook of the yokukansan drug, prevented migraines in this case through these multifaceted mechanisms.