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Preventive effects of parathyroid hormone‐related peptide on stress‐induced gastric hypercontraction in the rat
Author(s) -
ITO MASAHIRO,
NAKASHIMA MASAHIRO,
NAKAYAMA TOSHIYUKI,
SHIKUWA SABURO,
OHTSURU AKIRA,
SEKINE ICHIRO
Publication year - 2002
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1046/j.1440-1746.2002.02883.x
Subject(s) - medicine , endocrinology , motility , autocrine signalling , parathyroid hormone related protein , receptor , paracrine signalling , stomach , in vivo , parathyroid hormone , calcium , biology , microbiology and biotechnology
Background and Aims: Parathyroid hormone‐related peptide (PTHrP) appears to be a potent smooth muscle relaxant, but there has been no study of its effects on gastric motility in vivo . The purposes of this study were to evaluate the effects of external PTHrP on stress‐induced gastric motility in vivo and on the expression of PTHrP and PTH/PTHrP receptors in the rat stomach.Methods: Stress‐induced hypercontraction was evoked by restraint water immersion (RWI). Gastric motility was evaluated with a strain gauge force transducer, and the effects of external PTHrP‐(1–34) (10 µ i.p.) on gastric motility were examined. Expressions of PTHrP and PTH/PTHrP receptor mRNA were evaluated by RNase protection assay.Results: External PTHrP significantly suppressed abnormal contraction and mucosal lesions upon RWI stress. Upon RWI stress, the expression of PTHrP mRNA decreased, but that of PTH/PTHrP receptor mRNA was enhanced reciprocally. The PTH/PTHrP receptor was localized in smooth muscle cells of the muscle layers immunohistochemically.Conclusions: These findings suggest that smooth muscle contractile activity is modified by the autocrine/paracrine mechanism of PTHrP in the rat stomach and that the external PTHrP prevents stress‐induced hypercontraction and mucosal lesions. © 2002 Blackwell Publishing Asia Pty Ltd