Basic ResearchConstitutive expression and function of cyclooxygenase-2 in murine gastric muscles☆,☆☆
Section snippets
Animals and tissue preparation
Twenty-eight Balb-C, 6 C57/BL6 wild-type and COX-2 +/−, and 6 C57/BL6 COX-2 −/− mice of either sex between the ages of 25–35 days old (30–35 g) were used. Animals were suffocated by CO2 inhalation and killed by cervical dislocation followed by exsanguination. The abdomens were cut open and the stomach of each animal was removed for further dissection. The use and treatment of animals were approved by the Institutional Animal Use and Care Committee at the University of Nevada.
Immunohistochemical studies
Segments of fundus
Distribution of COX-2 immunoreactivity
We used immunohistochemical techniques to identify the cell types that express COX-2 in the tunica muscularis of the stomach. COX-2–like immunoreactivity (COX-2–LI) was found in a subpopulation of enteric nerve cell bodies and nerve terminals within myenteric ganglia of the fundus (Figure 1C) and antrum (Figure 1D and F).
Discussion
These experiments show constitutive expression of COX-2 in cells within the tunica muscularis of the mouse. The major expression of COX-2 was a subpopulation of enteric neurons and IC-IM. These findings suggest a new role of ICC as a source of paracrine substances that contribute to the regulation of gastrointestinal motility. Functional data suggest that prostanoids produced by COX-2 may contribute significantly to the spontaneously generated prostanoids that provide ongoing regulation of
Acknowledgements
The authors are grateful to Lisa Miller for excellent technical assistance in genotyping mice.
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Address requests for reprints to: Kenton M. Sanders, Ph.D., Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada 89557. e-mail: [email protected]; fax: (775) 784-6903.
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Supported by DK 40569 and a grant from Glaxo Smith Kline. Morphologic and molecular studies were supported by core laboratory facilities provided by DK 41513. Supported by a grant from the Fondation pour la Recherche Medicale (France) (to C.P.).