Abstract
As a neurotransmitter and avascular active substance, the 5-hydroxytryptamine (5-HT, serotonin) is widely distributed in the central nervous system and surrounding tissues. The 5-HT can play its role by acting on its corresponding 5-HT receptor. Nowadays, the 5-HT receptor can be classified into seven, according to different signal transduction method of receptors, the 5-HT3 receptor belongs to the ligand-gated ion channels, while other six 5-HT receptors are involved into the G protein-coupled receptors and play the biological role by binding to specific G protein-coupled receptors (GPCRs) on the surface of the cell membrane. The 5-HT plays an important role in the brain-gut information transmission and studies showed that the physiological stimulations like having meals, and pathological stimulations like ischemia and stress could promote the release of the 5-HT. In the gastrointestinal tract, the 5-HT is closely related to gastrointestinal sensitivity, gastrointestinal movement and secretion regulation, as well as many gastrointestinal dysfunction disorders, such as gastrointestinal power and visceral sensitivity abnormality and abnormalities of brain-gut axis.