Laxatives and the production of autacoids by rat colon

The effects of some laxatives were examined on the formation of histamine, 5-hydroxytryptamine (5-HT) and prostaglandin-like material (PG-LM) by rat intestine in-vitro. Castor oil, senna, sulphosuccinate and bisacodyl, but not mannitol or lactulose, in doses that cause laxation, increased the formation of histamine, 5-HT and PG-LM. Indomethacin or hydrocortisone reduced the increase of PG-LM formation. The data support the idea that the laxative effects of these intestinal secretagogues are due to increased intestinal production of PG-LM, histamine and 5-HT.