Effect of aldosterone on kinetics of intracellular sodium in cortical portion of collecting ducts in rat kidney

We studied the effect of protein kinase C inhibitor RO-31-8220 (10−7 M) on rapid nongenomic effect of aldosterone in cells of isolated segment of distal region of collecting duct in rat kidney. Experiments with fluorescent dye Na-Green showed that the inhibitor abolished the modulating effect of aldosterone (10 nM) on intracellular sodium concentration at external sodium concentration of 14 mM. Aldosterone decreased by half the initial rate of the changes in internal sodium concentration in both 10-day and mature rats (p<0.05). Similarly to sodium channel blocker amiloride (10−5 M), RO-31-8220 abolished rapid nongenomic effect of aldosterone on the rate of the changes in internal sodium concentration.