Specific inhibition of Ca‐activated K channels in red cells by selected dihydropyridine derivatives

1 Thirty two dihydropyridine derivatives were screened as potential inhibitors of the Ca‐activated K‐channel in human red cells. 2 Three derivatives (26, 29, 32 see Tables 1 and 2) with high activity were then characterized in detail, and also tested against the smooth muscle Ca‐channel and shown to have varying potencies. 3 One of the more potent derivatives (32) and nitrendipine were also tested on the Ca‐activated K‐channel, Maxi‐K channel, from mouse pancreatic beta‐cells. 4 We conclude from our results that it may be possible to develop selective Gardos‐channel inhibitors based on these molecules, which may be of benefit in the treatment of sickle cell disease.