Bronchodilating effects of the novel potassium channel opener HOE 234 in human airways in vitro.

Bronchodilating effects of the novel potassium channel opener HOE 234 were examined in human bronchi in vitro and compared with those of BRL 38227. HOE 234 produced concentration-dependent relaxations of spontaneous tone and of tone increased by methacholine (10(-6) M), with mean EC50 values of 11 nM and 47 nM, respectively (n = 5). The relaxation produced by HOE 234 was 7 and 3.5 fold more potent than that by BRL 38227 on spontaneous and induced tone, respectively, and was inhibited by glibenclamide (10(-5) M). These results suggest that HOE 234 is a potent bronchodilator which activates ATP-sensitive potassium channels in human airways.