In a reconstituted system, planar
lipid membrane measurements showed that the potassium channel
present in the A. castellanii inner mitochondrial membrane has a conductance ranging from 90 pS to 166 pS that is inhibited by 1 mM ATP/Mg2+ or glibenclamide and activated by diazoxide.
In mitochondria isolated from A. castellanii respiring with succinate, malate or external NADH, KATP channel openers (diazoxide and BMS-191095) cause an increase in respiration up to 15% and a slight but statistically significant depolarisation of DW up to 2 mV, while ATP and glibenclamide reverse these effects. Changes in respiratory rate and DW that are caused by ATP-sensitive potassium channel modulators are strictly dependent on the presence of K+ in the incubation medium (120 mM KCl has been used