Ketanserin
Ketanserin is a serotonin receptor antagonist. It has the highest affinity for the serotonin 5-HT2A receptor, but also binds less potently to the 5-HT2C, 5-HT2B, 5-HT1D, alpha-adrenergic, and dopamine receptors. With tritium radioactively labeled ketanserin is used as a radioligand for the serotonin 5-HT2A receptor, e.g. in receptor binding assays.