Effects of Bisacodyl on Colonic Motor Patterns in Rats

Objective: To explore the effects of bisacodyl on motor patterns in rat colon in vitro. Methods: 19 male rats were divided randomly into two groups: bisacodyl and saline group. Bisacodyl and saline were infused into the proximal or distal colon lumen; spatiotemporal mapping was used to quantify motor patterns. Results: (1) Proximal infusion of bisacodyl induced cluster long distance contractions (LDCs) with 3-8 LDCs in one cluster and frequency of 3/15 min; (2) Distal infusion of bisacodyl induced rhythmic LDCs and some cluster LDCs; (3) 0.9% NaCl infusion proximally or distally changed baseline LDCs into slow propagating rhythmic propulsion without cluster LDCs; (4) Both Bisacodyl and 0.9% NaCl infusion decreased the frequency of LDCs and increased the frequency of the proximal contractions. Conclusion: Bisacodyl infusion induces cluster LDCs and independent LDCs to promote colonic transit; Neurogenic mechanism possibly plays an important role according to the characteristics of the motor patterns.