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5‐HT activates neural reflexes regulating secretion in the guinea‐pig colon
Author(s) -
Cooke H. J.,
Sidhu M.,
Wang Y.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.d01-41.x
Subject(s) - reflex , cholinergic , endocrinology , atropine , substance p , acetylcholine , chemistry , medicine , guinea pig , capsaicin , vesicular acetylcholine transporter , piroxicam , serotonin , neuropeptide , receptor , alternative medicine , pathology , choline acetyltransferase
The role of 5‐hydroxytryptamine (5‐HT) in neural reflexes regulating secretion was examined in muscle‐stripped segments of guinea‐pig colon set up in modified flux chambers. A 15‐μL pulse of 5‐HT (100 μ M ) to the mucosal bath (1.5 mL), which was continuously perfused, evoked an increase in short‐circuit current (I sc ). The 5‐HT‐induced increase in I sc was inhibited by tetrodotoxin, N‐acetyl‐5‐hydroxytryptophyl‐5‐hydroxytryptophan amide (5‐HTP‐DP), GR82334 and atropine, but not by tropisetron. 5‐HTP‐DP reduced the response to a 5‐HT pulse over the concentration range of 1 n M to 1 μ M . The I sc response to a 5‐HT pulse was unaffected by the cyclooxygenase inhibitor, piroxicam. This contrasted with a reduction in the I sc response to mucosal stroking with a brush by piroxicam. The results suggest that a 5‐HT pulse, like mucosal stroking, activates a secretory reflex that includes tachykinin and cholinergic neurons but, unlike mucosal stroking, does not release prostaglandins.