Effects of gallanilide on intestinal smooth muscle

Gallanilide (GA) 400 mg/kg ig inhibited the passage of black ink from pylorus to appendix in mice. GA 1 microM or higher concentrations inhibited the spontaneous contraction of isolated guinea pig ileum. The stimulation of histamine (His) and acetylcholine (Ach) on the isolated guinea pig ileum was antagonized by GA in a non-competitive manner. The pD’2 values of GA for His and Ach were 5.84 and 4.4, respectively. GA 1 microM competitively antagonized the excitatory action of 5-HT and shifted the dose-response curve parallelly to the right. The pA2 value of GA for 5-HT was 6.96. GA 30 microM antagonized the 5-HT-induced contraction noncompetitively; the pD’2 of GA for 5-HT was 4.43. GA 3 microM as well as verapamil (Ver) 0.01 microM antaonized the stimulation of ouabain on the smooth muscle of ileum competitively. The pA2 values of GA and Ver were 6.04 and 8.06, respectively. On isolated guinea pig taenia coli preparations, GA 50 microM shifted the calcium dose-response curves to the right. GA 10 mM had no effect on the cAMP content of isolated guinea pig ileum.