WAY-100135

WAY-100135 is a serotonergic drug of the phenylpiperazine family which is used in scientific research. It acts as potent 5-HT_1A receptor antagonist, and was originally believed to be highly selective, but further studies have demonstrated that it also acts as a partial agonist of the 5-HT_1D receptor (pK_i = 7.58; virtually the same affinity for 5-HT_1A), and to a much lesser extent, of the 5-HT_1B receptor (pK_i = 5.82). These findings may have prompted the development of the related compound WAY-100635, another purportedly selective and even more potent 5-HT_1A antagonist, which was synthesized shortly thereafter. However, WAY-100635 turned out to be non-selective as well, having been shown to act additionally as a potent D₄ receptor agonist later on.