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Secretin induces variable inhibition of motility in different parts of the Australian possum sphincter of Oddi
Author(s) -
AlJiffry B. O.,
Jobling J. M.,
Schloithe A. C.,
Toouli J.,
Saccone G. T. P.
Publication year - 2001
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.1365-2982.2001.00278.x
Subject(s) - sphincter of oddi , secretin , motility , medicine , tetrodotoxin , endocrinology , migrating motor complex , chemistry , bile duct , pancreatic duct , gastroenterology , biology , pancreas , stomach , genetics
The sphincter of Oddi (SO) may not function as a single structure. We aimed to determine the response of the proximal and distal segments of the bile duct (BD‐SO) and pancreatic duct (PD‐SO) components of the SO to secretin, with and without neural blockade with tetrodotoxin (TTX). In anaesthetized Australian possums, separate manometry catheters were placed in the proximal and distal BD‐SO or PD‐SO segments to record motility. Secretin, 50–1000 ng kg –1 , was administered, followed by TTX, and re‐administration of secretin, 500 and 1000 ng kg –1 . Changes in the motility index (MI, frequency × mean amplitude) were determined. Statistical analysis utilized repeated‐measures ANOVA . Secretin produced a dose‐dependent decrease in MI from the proximal and distal BD‐SO and PD‐SO (all P < 0.001). The maximum inhibition, at 1000 ng kg –1 , was 21 ± 4%, 33 ± 6% and 42 ± 5% of control (mean ± SEM), for proximal and distal BD‐SO, and distal PD‐SO, respectively. The proximal PD‐SO MI, however, was inhibited to 62 ± 6% of control, at 1000 ng kg –1 . TTX enhanced the secretin‐induced response to the same level at the four sites (P < 0.02). We conclude that secretin inhibits the motility of the possum SO in a nonuniform manner and is modulated by neural activity.