Description: WAY-100135 (WAY100135) is a novel and potent serotonergic drug of the phenylpiperazine family for scientific research. It acts as potent 5-HT1A 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-HT1D receptor (pKi = 7.58; virtually the same affinity for 5-HT1A), and to a much lesser extent, of the 5-HT1B receptor (pKi = 5.82). These findings may have prompted the development of the related compound WAY-100,635, another purportedly selective and even more potent 5-HT1A antagonist, which was synthesized shortly thereafter.