Compounds of formula (I) wherein: R1, R2 and R3 are, independently, hydrogen, nitro, cyano, C1-10 haloalkoxy, amino, C1-10 alkylamino, sulfo, sulfamoyl, C1-10 alkylsulfonamido, C2-10 alkylcarboxamido C2-10 alkanoyl, C1-10 alkylsulfonyl, C1-10 haloalkylsulfonyl, C1-10 carboxyl, C1-10 haloalkyl and C6-12 aryl; with the provisos: (1) that R1, R2 and R3 may not all simultaneously be hydrogen, and (2) when R1 and R2 are hydrogen, R3 may not be meta-CF3; R4, R5 and R6 are, independently , hydrogen, halogen, nitro, cyano, C1-10 carboalkoxy, C1-10 haloalkoxy, amino C1-10 alkylamino, sulfo, sulfamoyl, C1-10 alkylsulfonamido, C2-10 alkylcarboxamido C2-10 alkanoyl, C1-10 alkylsulfonyl, C1-10 haloalkylsulfonyl, C1-10 carboxyl, C1-10 haloalkyl, C1-10 alkyl and C6-12 aryl; R7 is hydrogen , metal cation, acetylamido, alkoxyacetoyl or a related moiety which delivers the carboxylate in vivo; and X, Y and Z may form a C3-13 carbocyclic ring, oxazole, isoxazole, thiazole, isothiazole, furan, thiophene, 2H-pyrrole, pyrrole, 2-pyrroline, 3-pyrroline, imidazole, pyrazole, 1,2,3-oxadiazole or 1,2,3-triazole bound to the carbon skeleton; or pharmaceutically acceptable salts thereof useful in the treatment of disorders associated with smooth muscle contraction via potassium channel and chloride channel modulation.