WAY-100635 is a potent, silent antagonist of serotonin 5-HT1A receptors with an IC50 value of 2.2 nM (Ki = 0.8 nM) for inhibiting 5-HT1A receptors in rat hippocampal membranes. Because it displays 100-fold selectivity for 5-HT1A over other 5-HT subtypes, WAY-100635 is classically used to examine the distribution and function of 5-HT1A receptors. However, WAY-100635 has also been shown to exhibit agonist activity at dopamine D4 receptors (Kd = 2.4 nM).
