SDZ 205-557, a selective, surmountable antagonist for 5-HT4 receptors in the isolated guinea pig ileum

A selective antagonist for the recently characterized 5-HT₄-receptor is lacking. The only surmountable antagonist available, ICS 205-930, is a weak antagonist and is far more potent at 5-HT₃-than at 5-HT₄ receptors. In this paper, SDZ 205-557 (2-methoxy-4-amino-5-chloro-benzoic acid 2-(diethylamino) ethyl ester) is characterized as the first potent, selective and surmountable antagonist at 5-HT₄ receptors in the isolated guinea pig ileum.