Used primarily in research to study the role of serotonin in neurotransmission, particularly in mood, appetite, and sleep regulation. Employed in pharmacological studies to understand receptor subtypes and their responses in neurological and cardiovascular systems. Also utilized in assays to evaluate drug effects on serotonin pathways, including antidepressants and antiemetics. Plays a role in gastrointestinal motility studies due to its presence in enterochromaffin cells. Commonly used in cell culture and in vivo experiments to mimic physiological serotonin activity.