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Selective iNOS inhibition enhances spontaneous gallbladder motility in the Australian possum
Author(s) -
Woods C. M.,
Sandstrom P.,
Bond M.,
Michael M.,
Svanvik J.,
Toouli J.,
Saccone G. T. P.
Publication year - 2007
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/j.1365-2982.2007.00940.x
Subject(s) - gallbladder , contractility , nitric oxide synthase , motility , in vivo , medicine , nitric oxide , endocrinology , basal (medicine) , chemistry , biology , genetics , microbiology and biotechnology , insulin
Gallbladder inflammation is a common and painful disease. Inducible nitric oxide synthase (iNOS) plays a major role in inflammatory diseases, and iNOS inhibitors are being developed as therapeutic agents. Reports are inconsistent regarding iNOS expression in normal gallbladder. The aim of this study was to determine the effect of iNOS inhibition on spontaneous gallbladder motility. mRNA extracted from normal possum gallbladders was analysed by PCR. Gallbladder contractility was evaluated using a highly selective iNOS inhibitor AR‐C102222AA (AR‐C) in in vitro muscle strips (0.1–10 000 μ m) and in vivo (0.1–30 μ mol kg −1 ) experiments. Gene expression analysis revealed the presence of iNOS mRNA in normal gallbladder ( n = 3). In vitro , AR‐C (0.1–1000 μ mol L −1 ) produced a concentration‐dependent increase in spontaneous gallbladder contractile activity and basal tension ( P < 0.05; n = 6). The maximum effect was a 1.8‐fold increase in activity and 2.1‐fold increase in basal tension. Pretreatment of muscle strips with tetrodotoxin (1 μ mol L −1 ) did not block the AR‐C‐induced response ( n = 5). In vivo , AR‐C (30 μ mol kg −1 , i.v.) increased gallbladder contraction frequency ( P < 0.05; n = 8). These data suggest that iNOS is continually expressed in the normal gallbladder, which presumably releases low levels of nitric oxide and in turn may modulate spontaneous gallbladder motility. AR‐C may be a beneficial treatment for patients suffering from acute cholecystitis.