effects of substitution on 93bromo4fluorophenyl59dihydro3h4h26dioxa4 azacyclopentabnaphthalene18dione a dihydropyridine atpsensitive potassium channel opener structureactivity relationships were investigated on the tricyclic dihydropyridine dhp katp openers 93bromo4fluorophenyl59dihydro3h4h26dioxa4azacyclopentabnaphthalene18dione 6 and 103bromo4fluorophenyl910dihydro1h8h27dioxa9azaanthracene45dione 65 substitution off the core of the dhp absolute stereochemistry and aromatic substitution were evaluated for katp channel activity using ltk cells stably transfected with the kir62sur2b exon 17 splice variant and in an electrically stimulated pig bladder strip assay a select group of compounds was evaluated for in vitro inhibition of spontaneous bladder contractions several compounds were found to have the unique characteristic of partial efficacy in both the cellbased and electrically stimulated bladder strip assays but full efficacy in inhibiting spontaneous bladder strip contractions for compound 23b this profile was mirrored in vivo where it was fully efficacious in inhibiting spontaneous myogenic bladder contractions but only partially able to reduce neurogenically mediated reflex bladder contractions