EXPRESSION OF PROSTAGLANDIN-E(2) RECEPTOR IN HAMSTER BUCCAL POUCH - EFFECT OF BENZO(A)PYRENE AND NICOTINE

Prostaglandin E2 (PGE2) plays an important role in the maintenance of oral mucosal integrity. In this study, we characterized PGE2 receptor binding in the buccal mucosa of Syrian hamster and assessed the effect of nicotine (NC) and benzo (a) pyrene (BP), the two major ingredients in cigarette smoke, on this receptor. Adult male animals were treated for 4 weeks by apical swabbing of the buccal pouch with corn oil (con trol, C), 1 mM NC, BP, or NC + BP in corn oil, twice a day, 5 days a w eek. The results obtained with the untreated group revealed the presen ce of a specific PGE2 receptor consisting of two binding sites (high a ffinity with K(d) = 1.52 nM and B(max) = 37 fmol/mg protein and low af finity with K(d) = 813 nM and B(max) = 1.29 pmol/mg protein). The trea tment with NC, BP, and NC + BP caused a significant decrease in PGE2 r eceptor binding (specific binding: 10.20 +/- 0.42, 6.84 +/- 1.32*, 6. 58 +/- 0.67* and 5.88 +/- 1.03** fmol/mg protein; C, NC, BP, and NC BP, respectively; Mean +/- SD, n = 5, *p < 0.01). The data suggest t hat decreased receptor binding for PGE2 in the buccal mucosa may be th e cause for the adverse effect of cigarette smoke on the health of ora l mucosa.