Comparison of TX100-induced MEND and its influence on Na/K pump activity in a mouse myocyte, a BHK cell, and an HEK293 cell. All results use modified cytoplasmic solution (Lariccia et al., 2011) with 8 mM ATP and 0.2 mM GTP, and MEND is induced with 200 µM TX100. Pump currents are activated by applying and removing 6 mM KCl in exchange for 6 mM NaCl. Pump activation is evaluated both as pump current and as a capacitive signal that reflects a decrease of extracellular cation binding during pump activity. (A) Mouse myocyte. TX100 induces a 42% MEND response (>10 observations), whereas pump signals are decreased by 62%. Neither membrane area nor pump activity recovers over a 7-min observation period. (B) BHK cell. MEND amounts to 70% of membrane area, pump activity decreases by the same percentage, and both membrane area and pump activity recover over 8 min (four observations). (C) HEK293 cell. Na/K pump activity decreases over-proportionally to the loss of membrane area associated with MEND, and pump activity does not recover during the recovery of membrane area over 8 min (10 observations).