5-Hydroxytryptamine4 receptor agonists and colonic motility.
5-Hydroxytryptamine (5-HT) released from enterochromaffin cells regulates gastrointestinal function in either an excitatory or inhibitory manner. 5-HT(3) and 5-HT(4) receptors in the gut have been the focus of clinical studies on the management of gastrointestinal motility disorders. 5-HT stimulates intestinal propulsive reflexes through 5-HT(4) receptors. 5-HT(4) receptor agonists can stimulate upper or lower gut motility, depending on their selectivity and affinity. In the guinea pig colon, the distribution of 5-HT(4) receptors in the myenteric plexus and circular muscle layer differs between the proximal and distal regions. 5-HT stimulates intestinal motility via excitatory neurons while causing relaxation of the circular muscle via 5-HT(4) receptors. In the light of these findings on the distribution of 5-HT(4) receptors, the effects of receptor agonist compounds could vary depending on the species of experimental animal and the anatomical region studied.
Yongdong Severance Hospital Health Promotion Center, Yonsei University College of Medicine, Seoul, Korea.
Hee Sun
HS
Kim
D000818:Animals; D003106:Colon / Q000294:innervation* / Q000502:physiology*; D004759:Enterochromaffin Cells / Q000378:metabolism*; D005769:Gastrointestinal Motility / Q000187:drug effects* / Q000502:physiology; D006168:Guinea Pigs; D006801:Humans; D044406:Receptors, Serotonin, 5-HT3 / Q000378:metabolism; D044422:Receptors, Serotonin, 5-HT4 / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D058828:Serotonin 5-HT4 Receptor Agonists; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*
D044406:Receptors, Serotonin, 5-HT3; D058828:Serotonin 5-HT4 Receptor Agonists; D017366:Serotonin Receptor Agonists; D044422:Receptors, Serotonin, 5-HT4; D012701:Serotonin