Because serotonin signaling is widespread in both the central nervous system and the intestine, it comes as no surprise that compounds acting on multiple serotonin receptors may produce side effects. Although research has elucidated the involvement of certain subtypes in given indications, more work needs to be done to eliminate such side effects. Biotech companies are therefore developing technologies to select receptor subtypes that represent optimal targets for a selected indication (see "Serotonin Receptor Subtypes").

Last week Acadia Pharmaceuticals Inc. reported that the majority of marketed antipsychotics are potent inverse agonists of the serotonin 5-HT2A receptor, in