Bisacodyl

Bisacodyl is a stimulant laxative agent that works directly on the colon to produce a bowel movement. Bisacodyl increases the secretion of PGE₂ by direct activation of colon macrophages. PGE₂ acts as a paracrine factor and decreases the expression of AQP3 in the colon, which inhibits water transfer from the luminal to the vascular side and leads to a laxative effect^[1]. In Vivo:Bisacodyl (20 mg/kg) results in a decrease in AQP3 protein expression and increased mRNA expression level of TNF-α in the colon of rats^[1].
Bisacodyl inhibits water absorption in rat jejunum, ileum, and colon, the degree of inhibition is linearly related to the logarithm of the bisacodyl concentration over the range of 0.05 mg to 2.0 mg per 100 mL^[2].
Bisacodyl (10 mg/kg, intragastrically) induces a significant decrease in jejunal NOS activity in rats. Bisacodyl (10 mg/kg, intragastrically) increases the distance traveled by the marker in all time periods^[3].
Bisacodyl (5.9 mg/kg) decreases significantly jejunal and colonic (Na + K) ATPase activity as compared to saline-treated rats. Bisacodyl (5.9 mg/kg) increases significantly jejunal and colonic PGE2 content and stimulates jejunal and colonic adenyl cyclase activity as compared to those in control rats without affecting cAMP content^[4].
Bisacodyl (4.3 mg/kg) coupled with AOM increases the number of crypt per focus, but not the number of tumors in rats. Bisacodyl (43 mg/kg) significantly increases the number of crypt per focus and tumors in rats^[5].