Effects of fractionated doses of ionizing radiation on colonic motor activity

M. F. Otterson, S. K. Sarna, S. C. Leming, J. E. Moulder, J. G. Fink

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


The colonic motor effects of fractionated irradiation were studied in five conscious dogs. Seven colonic and two ileal strain gauge transducers were implanted. After control recordings, an abdominal dose of 250 cGy was administered three times a week on alternate days for three successive weeks (total dose 2,250 cGy). Recordings were then continued for 3 wk after the completion of radiation. Colonic giant migrating contractions (GMCs) occurred at a frequency of 0.15 ± 0.05 contractions/h in the control state. Only one of these contractions (8.3%) originated in the small bowel and propagated into the colon. Abdominal field irradiation significantly increased the incidence of colonic GMCs to 0.51 ± 0.11 contractions/h (P < 0.05). Fifty- four percent of GMCs originated in the small intestine. GMCs during the radiation schedule were associated with explosive diarrhea on seven occasions. Irradiation did not alter the frequency of colonic migrating motor complexes, but the mean duration of contractile states decreased in the middle and distal colon. Diarrhea occurred as early as the second dose of radiation. Pathological changes in the colon were correlated with motor activity. Both small intestinal and colonic GMCs reverted to control frequencies after cessation of radiation exposure. Abdominal irradiation significantly altered the contractile activity of the colon. These changes are associated with abdominal cramping and diarrhea.

Original languageEnglish (US)
Pages (from-to)G518-G526
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Issue number4 26-4
StatePublished - 1992
Externally publishedYes


  • diarrhea
  • gastrointestinal motility
  • migrating motor complex
  • radiation effects

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)


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