WAY-100635

WAY-100635 is a piperazine research chemical originally developed as a selective serotonin 5-HT1A receptor antagonist. It was designed to act as a "silent antagonist" at 5-HT1A receptors, meaning it blocks receptor activity without exhibiting any intrinsic agonist properties. The compound displays high binding affinity for 5-HT1A receptors with an IC50 of 1.35 nM and demonstrates over 100-fold selectivity relative to other CNS receptors. However, subsequent research revealed that WAY-100635 is **not** truly selective for 5-HT1A receptors. It acts as a potent full agonist at dopamine D4 receptors with high binding affinity (Ki = 3.3 nM for D4.4 receptors), comparable to its 5-HT1A affinity. The compound also shows weak antagonist activity at D2 receptors. This dual activity has important implications for interpreting studies that used WAY-100635 as a "selective" 5-HT1A antagonist. WAY-100635 has been extensively used as a radioligand (particularly [11C]WAY-100635 and [3H]WAY-100635) for PET imaging studies of 5-HT1A receptor distribution in the brain. It was developed by **Wyeth** and has been investigated for potential therapeutic applications in anxiety disorders, cognitive disorders, and other neuropsychiatric conditions, though development has been discontinued.

Other names

N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamideN-[2-[4-(2-Methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide trihydrochloride