Effects of a meal and bisacodyl on colonic motility in healthy volunteers and patients with slow-transit constipation

In the present study, the gastrocolonic response after ingestion of a standardized liquid meal and the response to a local chemical stimulus were investigated in 10 healthy volunteers and 10 patients with slow-transit constipation ( as determined by marker studies). Colonic pressures were recorded while fasting, after ingestion of a standardized meal and after intracolonic bisacodyl infusion, using a 12-channel water-perfused catheter. Pressure waves propagating over at least 20 cm (HAPPW) were identified visually and automated analysis was carried out on remaining segmental motility. Increases of motility after a meal and bisacodyl were seen in healthy subjects, whereas patients did not show these responses. The time until occurrence of the first HAPPW after bisacodyl infusion tended to be prolonged (4.3 +/- 1.4 vs 36.1 +/- 15.3; P = 0.053) and the number of HAPPWs in the first 30 min. after infusion was lower compared to healthy subjects (2.1 +/- 0.2 vs 5.4 +/- 0.3; P < 0.01). The percentage of HAPPWs that were experienced as urge or cramp was significantly lower in constipated patients (53 +/- 3% vs 95 +/- 1%; P < 0.005). In conclusion, this study shows that in patients with slow-transit constipation, the colonic motor response to a meal and to bisacodyl, as well as the perception of bisacodyl-induced propagated pressure waves is decreased.