Inhibition of small intestine motility by cromakalim (BRL 34915)

The effects of the potassium channel activator, cromakalim, on intestine motility were investigated. In vitro, cromakalim inhibits the peristaltic reflex, with the action on longitudinal muscle (pIC50 = 5.8 +/- 0.1) being more potent than that on circular muscle (pIC50 = 4.8 +/- 0.2). In vivo, a half maximal inhibition of small intestinal transit occurred at 1.2 mg/kg (i.p.). These results demonstrate that different gut muscle layers show a different sensitivity to cromakalim and that small intestine smooth muscle is less sensitive to cromakalim than vascular smooth muscle.