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Effect of 5‐hydroxytryptamine on gastrointestinal motility in conscious guinea‐pigs
Author(s) -
Nakajima M.,
Shiihara Y.,
Shiba Y.,
Sano I.,
Sakai T.,
Mizumoto A.,
Itoh Z.
Publication year - 1997
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1046/j.1365-2982.1997.d01-56.x
Subject(s) - 5 ht receptor , antrum , methysergide , atropine , ketanserin , serotonin , ileum , medicine , endocrinology , motility , cholinergic , receptor , biology , stomach , genetics
Many studies have suggested that 5‐hydroxytryptamine (5HT, serotonin) plays an important role in the control of gastrointestinal motility. However, most of these studies have been carried out on guinea‐pig ileum in vitro. Therefore, we investigated the mechanisms of action of 5HT on gastrointestinal motility in conscious guinea‐pigs. In order to investigate the effects of 5HT on gastrointestinal motility, extraluminal force transducers were sutured onto the serosal surfaces of the gastric antrum, duodenum and ileum and 5HT was infused intravenously. One of three types of 5HT antagonist or atropine was given before a 5HT infusion of 3.0 μg kg −1 min −1 was started. Regular cyclic patterns were observed from the gastric antrum to the ileum in both the fasted and fed states. 5HT increased the contraction amplitudes at all sites. 5HT‐induced contractions in the gastric antrum and duodenum were significantly inhibited by methysergide, ondansetron and atropine, but not by ketanserin. In the ileum, only atropine inhibited 5HT‐induced contractions. These results suggest that 5HT increases the gastrointestinal contraction amplitude mainly via a cholinergic pathway. 5HT 3 receptors and 5HT 1 ‐like and/or 5HT 2C receptors appear to be responsible for 5HT‐induced gastric antral and duodenal contractions, but 5HT receptors other than 5HT 1 ‐like, 5HT 2A , 5HT 2C and 5HT 3 receptors induce ileal contractions.