Non-competitive inhibition of bradykinin, acetylcholine and histamine on guinea-pig ileum with streptomycin and vitamin K3.

Streptomycin and vitamin K3 were studied on the guinea-pig ileum for their effects on the cumulative dose-response curves of bradykinin, acetylcholine and histamine. Streptomycin and vitamin K3 antagonized each of these agonists non-competitively. The comparison of the non-competitive affinities of the antagonists indicate that all of these agonists antagonized by a common mechanism.