Author:
Jernigan Nikki L.,Drummond Heather A.
Abstract
Mechanosensitive ion channels are thought to initiate pressure-induced vasoconstriction, however, the molecular identity of these channels is unknown. Recent work from our laboratory suggests that members of the Degenerin/Epithelial Na+ Channel (DEG/ENaC) family may be components of the mechanosensitive ion channel complex in vascular smooth muscle (VSM); however, the specific DEG/ENaC proteins mediating myogenic constriction are unknown. The goal of this study is to determine if specific knockdown of β or γENaC, using dominant-negative (DN) or small-interference RNA (siRNA) molecules, inhibits pressure-induced vasoconstriction in mouse renal interlobar arteries. To address this goal, isolated arteries were transiently transfected with β or γENaC DN-cDNA or siRNA molecules. After 24 h, vessels were either 1) cannulated and pressurized for pressure-diameter response curves or 2) dissociated and immunolabeled to determine VSM cell endogenous ENaC protein expression. We found that transfection of βENaC DN-cDNA or siRNA suppresses β-, but not γENaC protein expression. Similarly, γENaC DN-cDNA or siRNA suppresses γ-, but not βENaC protein expression. In addition, transfection of β- or γENaC DN-cDNA or siRNA molecules inhibits pressure-induced vasoconstriction, but does not block agonist-induced vasoconstriction. Our results provide the first direct evidence that β and γENaC proteins are essential in mediating myogenic vasoconstriction in mouse renal interlobar arteries.
Publisher
American Physiological Society
Cited by
95 articles.
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