Serotonin or 5-hydroxytryptamine (5-HT Receptor) is a monoamine neurotransmitter, derivative from the amino acid tryptophan, and mainly located in the enterochromaffin cells in the GI tract and central nervous system (CNS). It has a popular image as a contributor to feelings of well-being and happiness, though its actual biological function is complex and multifaceted, modulating cognition, reward, learning, memory, and numerous physiological processes. Serotonin receptors, are a group of G protein-coupled receptor and ligand-gated ion channels found in the central and peripheral nervous systems. They can be divided into 7 families of G protein-coupled receptors except for the 5-HT3 receptor, a ligand-gated ion channel, which activate an intracellular second messenger cascade to produce an excitatory or inhibitory response. They mediate both excitatory and inhibitory neurotransmission, influencing various biological and neurological processes. The serotonin receptors are the target of a variety of pharmaceutical and recreational drugs, including many antidepressants, antipsychotics, anorectics, antiemetics, gastroprokinetic agents, antimigraine agents, hallucinogens, and entactogens.

The Serotonin (5-HT) Compound Library by TargetMol, collecting 268 small chemicals targeting serotonin receptors, can be used for high throughput screening and high content screening, and drug discovery in neurological disorders.