title: Effects of 5-HT2B, 5-HT3 and 5-HT4 receptor antagonists on gastrointestinal motor activity in dogs.
abstract: OBJECTIVE
  To study the effects of 5-hydroxytryptamine (5-HT) receptor antagonists on normal colonic motor activity in conscious dogs.
  
  
  METHODS
  Colonic motor activity was recorded using a strain gauge force transducer in 5 dogs before and after 5-HT2B, 5-HT3 and 5-HT4 receptor antagonist administration. The force transducers were implanted on the serosal surfaces of the gastric antrum, terminal ileum, ileocecal sphincter and colon. Test materials or vehicle alone was administered as an intravenous bolus injection during a quiescent period of the whole colon in the interdigestive state. The effects of these receptor antagonists on normal gastrointestinal motor activity were analyzed.
  
  
  RESULTS
  5-HT2B, 5-HT3 and 5-HT4 receptor antagonists had no contractile effect on the fasting canine terminal ileum. The 5-HT3 and 5-HT4 receptor antagonists inhibited phase III of the interdigestive motor complex of the antrum and significantly inhibited colonic motor activity. In the proximal colon, the inhibitory effect was dose dependent. Dose dependency, however, was not observed in the distal colon. The 5-HT2B receptor antagonist had no contractile effect on normal colonic motor activity.
  
  
  CONCLUSIONS
  The 5-HT3 and 5-HT4 receptor antagonists inhibited normal colonic motor activity. The 5-HT2B receptor antagonist had no contractile effect on normal colonic motor activity.
authors.affiliation: Hiroki Morita, Erito Mochiki, Akira Watanabe, Toshinaga Sutou, Atsushi Ogawa, Mitsuhiro Yanai, Kyoichi Ogata, Takaaki Fujii, Tetsuro Ohno, Souichi Tsutsumi, Takayuki Asao, Hiroyuki Kuwano, Department of General Surgical Science (Surgery 1), Gunma University, Graduate School of Medicine, Gunma 371-8511, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Morita
authors.forename: Erito
authors.initials: E
authors.lastname: Mochiki
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kawamura
authors.forename: Akira
authors.initials: A
authors.lastname: Watanabe
authors.forename: Toshinaga
authors.initials: T
authors.lastname: Sutou
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ogawa
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yanai
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Ogata
authors.forename: Takaaki
authors.initials: T
authors.lastname: Fujii
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Ohno
authors.forename: Souichi
authors.initials: S
authors.lastname: Tsutsumi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Asao
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwano
mesh_terms: D000818:Animals; D003106:Colon / Q000187:drug effects / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism; D005769:Gastrointestinal Motility / Q000187:drug effects*; D041981:Gastrointestinal Tract / Q000187:drug effects* / Q000378:metabolism; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D016065:Myoelectric Complex, Migrating / Q000187:drug effects; D044403:Receptor, Serotonin, 5-HT2B / Q000187:drug effects* / Q000378:metabolism; D044406:Receptors, Serotonin, 5-HT3 / Q000187:drug effects* / Q000378:metabolism; D044422:Receptors, Serotonin, 5-HT4 / Q000187:drug effects* / Q000378:metabolism; D058830:Serotonin 5-HT2 Receptor Antagonists / Q000494:pharmacology*; D058831:Serotonin 5-HT3 Receptor Antagonists / Q000494:pharmacology*; D058832:Serotonin 5-HT4 Receptor Antagonists / Q000494:pharmacology*; D013270:Stomach / Q000187:drug effects; D013997:Time Factors; D014160:Transducers, Pressure
chemical_list: D044403:Receptor, Serotonin, 5-HT2B; D044406:Receptors, Serotonin, 5-HT3; D058830:Serotonin 5-HT2 Receptor Antagonists; D058831:Serotonin 5-HT3 Receptor Antagonists; D058832:Serotonin 5-HT4 Receptor Antagonists; D044422:Receptors, Serotonin, 5-HT4
keywords: 5-hydroxytryptamine receptor antagonist; Colonic motility; Irritable bowel syndrome