Background/aims: The aim of this study was to analyze the defecation function, in particular the development of the gastrocolic reflex arising in coordination with the upper gastrointestinal tract, in patients with chronic constipation of the slow transit type (STC).
Methodology: The rectal movement types in adult patients with STC were compared with those in normal subjects as a control. A force transducer was inserted transanally into the rectum of 10 patients with STC (Group A), and the intrarectal pressure waveforms were recorded for 2 hours before and after the ingestion of test diets. Similar recordings were obtained from control subjects who had no abnormalities of defecation (Group B).
Results: On the basis of the recordings obtained pre- and postprandially, the waveforms in the Group B subjects were classified into 4 types (Type I, continuous waves of low amplitude; Type II, continuous waves of high amplitude or with elevation of basal tone; Type III, only elevation of the basal tone; Type IV, monophasic contraction waves). In fasting state, only Type I waves were recorded in both Group A and B subjects. Postprandially, all the subjects in both the groups showed Type I waveforms. In addition, the frequency of this type of waveform was significantly increased in Group B (p < 0.01). Type III and IV waveforms were also recognized only in Group B. There was no difference in the frequency of Type II waveforms between Groups A and B, but the time required for the appearance of Type II waveforms after ingestion of the test diet was significantly (p < 0.01) shorter in Group B than in Group A. Thus, there were no differences in the preprandial movement type between the 2 groups. However, postprandially, in Group A, the appearance of continuous waves of high amplitude was delayed, although their frequency was not significantly increased, as compared to those in Group B, and there were few giant contraction waves.
Conclusions: Functional disturbances of the rectal movements were recognized after food ingestion in patients with STC, and this result was considered to be attributable to decreased strength of the gastrorectal reflex.