5-Hydroxytryptamine (5-HT, also commonly known as serotonin) is synthesized in enterochromaffin cells in the intestine and in serotonergic nerve terminals. In the periphery, 5-HT mediates gastrointestinal motility, platelet aggregation, and contraction of blood vessels. Many functions of the central nervous system are influenced by 5-HT, including sleep, motor activity, sensory perception, arousal, and appetite. A family of 12 GPCRs and one ion channel mediate the biological effects of 5-HT (Hoyer et al., 1994). 5HT2C is expressed in the brain and spinal cord, especially the choroid plexus. 5HT2C receptor agonists may have important clinical value in the treatment of mental and eating disorders, such as depression, panic anxiety, OCD, bulimia, and obesity. GenScript's cloned human 5-HT2C expressing cell line is generated in the CHO-K1 host.