Compounds of formula I:
are used as antagonists and partial agonists for the serotonin receptor 5-HT4 and provide therapeutic methods for treatment of disorders caused by or affected by dysfunction of the 5-HT4 receptor.
Compounds of formula I: ##STR1## are used as antagonists and partial agonists for the serotonin receptor 5-HT.sub.4 and provide therapeutic methods for treatment of disorders caused by or affected by dysfunction of the 5-HT.sub.4 receptor.