Gastric diversion or pylorus ligation for gastric mucosal integrity and acid secretion studies in the rat?

The advantages of gastric diversion over pylorus ligation in rat gastric mucosal integrity and acid secretion studies over 6 hr were investigated. Mucosal injury developed in 80% of pylorus-ligation controls. Atropine (5 mg/kg) or cimetidine (40 mg/kg) had no effect on this injury (2.9 mm2 +/- 0.9 and 2.8 mm2 +/- 0.7, respectively, vs 3.1 mm2 +/- 1, mean +/- SEM, N = 10); however vagotomy increased it (13.7 mm2 +/- 1.5, mean +/- SEM, N = 10, P less than 0.001). Gastric diversion produced no mucosal injury. Pylorus-ligation H+ output was higher than that of gastric diversion (390.5 mumol +/- 54.8 vs 61 mumol +/- 2.5, mean +/- SEM, N = 10, P less than 0.001). Cimetidine (40 mg/kg) depressed H+ output of gastric diversion (21.3 mumol +/- 1.2 vs 61 mumol +/- 2.5, mean +/- SEM, N = 10, P less than 0.001), but not of pylorus ligation (424 mumol +/- 74.2 vs 390.5 mumol +/- 54.8, mean +/- SEM, N = 10). Vagotomy or atropine depressed pylorus-ligation H+ output (P less than 0.001), but each allowed an output (36.6 mumol +/- 5.5 and 120 mumol +/- 29, respectively, mean +/- SEM, N = 10) significantly (P less than 0.001) higher than that associated with it in gastric diversion (16 mumol +/- 1.4 and 17.1 mumol +/- 1.6, respectively, mean +/- SEM, N = 10). This study demonstrates that in the rat pylorus ligation, in contrast to gastric diversion, injures the gastric mucosa, stimulates H+ secretion, and overshadows the efficacy of antisecretory agents.