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. 2011 Jun 15;31(24):8998–9009. doi: 10.1523/JNEUROSCI.6684-10.2011

Figure 1.

Figure 1.

Total GI transit time, small intestine transit, and colonic motility are decreased but gastric emptying is accelerated in mice that lack TPH2 or TPH1 and TPH2. A, Carmine red was administered orally, and the time to development of red stools was noted. GI transit time in TPH1KO, TPH2KO, and TPH1/2dKO mice was compared, respectively, with that of wild-type littermates. Total GI transit time was increased (slower than littermates) in TPH2KO and TPH1/2dKO animals; however, the total GI transit time in TPH1KO mice did not differ from that of their wild-type littermates. Total GI transit time in TPH1/2dKO animals was not different from that in mice lacking only TPH2. B, Gastric emptying was measured after gavage of rhodamine dextran. The percentage of administered rhodamine dextran that emptied from the stomach in 15 min was determined in TPH1KO, TPH2KO, and TPH1/2dKO mice and compared with that of their respective wild-type littermates. The proportion of gastric contents that emptied was greater in TPH2KO and TPH1/2dKO animals than in the respective littermates; however, gastric emptying in TPH1KO mice did not differ from that in their wild-type littermates. Gastric emptying in TPH1/2dKO animals was not different from that in mice lacking only TPH2. C, Small intestinal transit was studied by measurement of geometric center of rhodamine dextran. The numbers of the geometric center, 1–10, represent slow to fast small intestine transit. Small intestinal transit was significantly slower in TPH2KO and TPH1/2dKO animals than in their respective wild-type littermates; however, small intestinal transit in TPH1KO mice did not differ significantly from that of their wild-type littermates. Small intestinal transit in TPH1/2dKO animals was not different from that in mice lacking only TPH2. D, Colonic motility was estimated by measuring the time required to expel a glass bead inserted into the rectum for a distance of 2 cm. This time was significantly greater (slower motility) in TPH2KO and TPH1/2dKO animals than in their respective wild-type littermates; however, the time to expel the bead in TPH1KO mice did not differ significantly from that in their wild-type littermates. The time required to expel the bead in TPH1/2dKO mice was not significantly different from that in mice lacking only TPH2. ns, Not significant.