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.