A series of N-azabicycloalkyl-1-alkyl-2-oxo-1, 2-dihydro-3-quinolinecarboxamides were synthesized and tested for serotonin 5-HT 4 receptor-stimulating effects in the regulation of electrically-evoked contraction in guinea pig muscle. Among them, N-azabicycloalkyl-1- isopropyl-2-oxo-1, 2-dihydro-3-quinolinecarboxamide (8c, 9c, 10c, 11c, 12c) exhibited potent serotonin 5-HT 4 receptor-stimulating activity. The most potent compound, N-(endo- ...