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Serotonin‐induced contractile responses of esophageal smooth muscle in the house musk shrew ( Suncus murinus )
Author(s) -
Shiina T.,
Naitou K.,
Nakamori H.,
Suzuki Y.,
Horii K.,
Sano Y.,
Shimaoka H.,
Shimizu Y.
Publication year - 2016
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 - 10.1111/nmo.12863
Subject(s) - suncus , esophagus , serotonin , endocrinology , cholinergic , medicine , 5 ht receptor , acetylcholine , receptor , biology , agonist , peristalsis , serotonin antagonists
Background Serotonin (5‐hydroxytryptamine, 5‐ HT ) is a regulatory factor in motility of the gastrointestinal tract including the esophagus. Although we proposed that vagal cholinergic and mast cell‐derived non‐cholinergic components including serotonin coordinately shorten the esophagus, the precise mechanism of serotonin‐induced contractions in the suncus esophagus is still unclear. Therefore, the aims of this study were to determine characteristics of contractile responses induced by serotonin and to identify 5‐ HT receptor subtypes responsible for regulating motility in the suncus esophagus. Methods An isolated segment of the suncus esophagus was placed in an organ bath, and longitudinal or circular mechanical responses were recorded using a force transducer. Key Results Serotonin evoked contractile responses of the suncus esophagus in the longitudinal direction but not in the circular direction. Tetrodotoxin did not affect the serotonin‐induced contractions. Pretreatment with a non‐selective 5‐ HT receptor antagonist or double application of 5‐ HT 1 and 5‐ HT 2 receptor antagonists blocked the serotonin‐induced contractions. 5‐ HT 1 and 5‐ HT 2 receptor agonists, but not a 5‐ HT 3 receptor agonist, evoked contractile responses in the suncus esophagus. Conclusion & Inferences The findings suggest that serotonin induces contractile responses of the longitudinal smooth muscle in the muscularis mucosae of the suncus esophagus that are mediated via 5‐ HT 1 and 5‐ HT 2 receptors on muscle cells. The serotonin‐induced contractions might contribute to esophageal peristalsis and emetic response.