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Protease‐activated receptor‐2 (PAR‐2) in the rat gastric mucosa: immunolocalization and facilitation of pepsin/pepsinogen secretion

2002; Wiley; Volume: 135; Issue: 5 Linguagem: Inglês

10.1038/sj.bjp.0704562

1476-5381

Naoyuki Kawao, Yuriko Sakaguchi, Ai Tagome, Ryotaro Kuroda, Shozo Nishida, Kiyohiro Irimajiri, Hiroyuki Nishikawa, Kenzo Kawai, Morley D. Hollenberg, Atsufumi Kawabata,

Coagulation, Bradykinin, Polyphosphates, and Angioedema

1. Agonists of protease-activated receptor-2 (PAR-2) trigger neurally mediated mucus secretion accompanied by mucosal cytoprotection in the stomach. The present study immunolocalized PAR-2 in the rat gastric mucosa and examined if PAR-2 could modulate pepsin/pepsinogen secretion in rats. 2. PAR-2-like immunoreactivity was abundant in the deep regions of gastric mucosa, especially in chief cells. 3. The PAR-2 agonist SLIGRL-NH(2), but not the control peptide LSIGRL-NH(2), administered i.v. repeatedly at 0.3 - 1 micromol kg(-1), four times in total, significantly facilitated gastric pepsin secretion, although a single dose produced no significant effect. 4. The PAR-2-mediated gastric pepsin secretion was resistant to omeprazole, N(G)-nitro-L-arginine methyl ester (L-NAME) or atropine, and also to ablation of sensory neurons by capsaicin. 5. Our study thus provides novel evidence that PAR-2 is localized in mucosal chief cells and facilitates gastric pepsin secretion in the rats, most probably by a direct mechanism.