Serotonin(5-HT)in the human gut 5-HT15-HT35-HT4 Gastric accommodation Transit Colonic tone Sensation SecretionSerotonin(5-HT) in the human gut 5-HT1 5-HT3 5-HT4 Gastric accommodation ↑ ↑ Transit ↓ ↑ ↑ Colonic tone ↓ ↑ Sensation ↑ ? Secretion ↑