In Vitro Motor Activity of Rat Small Intestine Following Whole-Body X Irradiation

摘要

In vitro contractions of small intestinal segments were studied at varying times following exposure of rats to whole-body x irradiation. Jejunal contractions were measured 20 to 40 minutes, 4 to 6 hours, 1 day, 2 days, 3 days, 5 days, 7 days, 11 days and 30 days following 25 R, 100 R, and 700 R, as well as during the first 3 days following 1500 R. Duodenum and ileum were studied 2 and 3 days following 1500 R. Sham irradiated rats served as controls. The irregular 'multicomponent' contraction pattern characteristic of jejunal segments from nonirradiated rats was changed to a more regular pattern 2 and 3 days after 1500 R, 700 R, and 100 R; in addition, exposures with 1500 R and 700 R increased contraction amplitude. Two and three days following 1500 R, duodenal but not ileal segments showed increased regularity. Furthermore, the gradient of contraction frequency (duodenum>jejunum>ileum) was maintained, but the gradient of contraction regularity (ileum>jejunum>duodenum) was changed. Changes in small intestinal motor function following whole-body radiation may significantly contribute to the pathophysiology of intestinal radiation injury. (Author)