... of a 170 kDa membrane protein identified as P-glycoprotein and reversal of resistance by verapamil and quinine. Compared with NG108-15 cells, NG/DOXR cells showed an increase in Na + current density and a decrease in cyclic-AMP-activated Cl − current density with no change in K + - and volume-sensitive Cl...

..., exhibited an apparent 1:1 transport stoichiometry and possessed a minimal divalent cation specificity. Calcium transport at this epithelial pole occurred by the combination of a Ca 2+ /Na + antiporter, an ATP-dependent Ca 2+ -ATPase and a verapamil-sensitive calcium channel. These crustacean brush-border...

..... The overshoot of the APs was unaffected by the addition of tetrodotoxin (3 μmol 1 −1 ) or the removal of Na + (choline replacement) from the bathing saline. APs could be reversibly blocked by 1 mmol l − La or 10 mmol 1 −1 Co 2+ . Verapamil at 50μmoll −1 and 100μmoll −1 reduced AP duration by 30% and 50...