UCL1684: a potent blocker of Ca2+-activated K+ channels in rat adrenal chromaffin cells in culture

The novel K+ channel blocker 6,10-diaza-3(1,3)8,(1,4)-dibenzena-1,5(1,4)-di quinolinacyclodecaphane (UCL 1684) has been tested for its ability to inhib it Ca2+-activated K+ currents in cultured rat chromaffin cells. Low nanomol ar concentrations of UCL 1684 produced a rapid and reversible inhibition of the slow, apamin-sensitive, tail current activated by a depolarizing volta ge command. This compound also inhibited the muscarine activated outward cu rrent with an IC50 of 6 nM. These results confirm UCL 1684 to be the most p otent non-peptidic blocker of the apamin-sensitive Ca2+-activated K+ channe l so far described. (C) 1999 Elsevier Science B.V. All rights reserved.