Response to Role of Epithelial Sodium Channels in the Renal Myogenic Response?

摘要

We appreciate the comments from Loutzenhiser and Aaronson1 regarding our report2 that afferent arteriolar autoregulation was inhibited by amiloride or benzamil (bath; 10 μmol/L) and by perfusion with 5 μmol/L of amiloride. In both conditions, KCl-induced vasoconstriction was preserved, indicating intact voltage-dependent Ca2+ channel function. With immunofluorescent detection of the epithelial sodium channel (ENaC) subunits (α, β, and γ), the data support the hypothesis that ENaC-like proteins may function as mechanosensitive ion channel complexes transducing myogenic responses.As noted, amiloride and benzamil can inhibit other channels and transporters, but they generally require concentrations greater than those used here. The IC50 for amiloride inhibiting the Na+/H+ exchanger is 84 μmol/L and 1100 μmol/L for the Na+/Ca2+ exchanger.3 Benzamil is 10 …