PHYSIOLOGICAL CORRELATES OF COLONIC MOTILITY IN PATIENTS WITH IRRITABLE-BOWEL-SYNDROME

Irritable bowel syndrome is frequently encountered in clinical practic e, and it has been repeatedly suggested that abnormal colonic motor ac tivity is one of the major pathophysiological mechanisms responsible f or the origin of symptoms in such disorder. Lf this statement is true, then high-amplitude propagated colonic contractions (HAPCs), i. e. th e mass movements. may play an important role. To test this hypothesis, we conducted an investigation by recording colonic motility for a pro longed (24 h) period in 25 patients with irritable bowel syndrome and in 18 healthy volunteers, to compare the number of mass movements over 24, h in patients (constipation-predominant, alternating bowel habits ) and controls. The overall amount of motility was also assessed in tw elve patients and 13 controls. We also looked for the possible changes in mass movements and motility which may occur with defecation and af ter a meal. The results showed that 1) with respect to HAPCs and motil ity index, neither group was significantly different from controls; 2) HAPCs and the motilit)i index were significantly reduced during sleep in all groups tested; 3) HAPCs were significantly more common be fore as compared to after defecation and after as compared to before meals 4) HAPCs are not independent from the segmental contractile activity; 5) the motility index/24 h was lower in the constipation-predominant group of patients with respect to controls. We conclude that in patien ts with irritable bowel syndrome colonic motility per se may play a pa thophysiological role in the genesis of the symptoms, although other m echanisms are likely to concur, or to be responsible for the com plain ts of these patients. However, colonic prolonged recordings are very u seful for studying physiological and pathophysiological correlates of sleep: eating, and defecation.