The effect of a low Na+, high K+ diet on Na+,K+-ATPase levels in cochlear lateral wall tissues was investigated in laboratory rats by using an enzyme-linked immunosorbent assay. The low Na+, high K+ diet induced high aldosterone plasma levels in the animals as well as changes in plasma cation levels. Animals that received a low Na+, high K+ diet demonstrated a statistically significant (97%) increase in Na+,K+-ATPase levels in the stria vascularis when compared to animals that received a control diet. This increase in strial Na+,K+-ATPase levels was blocked only 70% by administration of the aldosterone antagonist, spironolactone. Findings therefore indicate that strial Na+,K+-ATPase may be modulated by both aldosterone and Na+,K+ plasma levels. Na+,K+-ATPase levels in the spiral ligament were not affected by the experimental treatment. These findings suggest that spiral ligament Na+,K+-ATPase levels may be regulated by factors other than aldosterone and Na+,K+ plasma levels. This study provides further insight into the mechanisms of the beneficial effects of salt restriction and potassium loading in patients with Méniére's disease. © 1994 Springer-Verlag.