Abstract 15995: Role of Kir Channels in Flow-Induced Vasodilatation

Introduction: Flow-induced vasodilation (FIV) is an important physiological stimulus for regulating vascular tone. A loss of endothelial-dependent FIV is an early indication of endothelial dysfunction. Earlier studies proposed that endothelial inwardly-rectifying K+ channels (Kir) are putative flow sensors, but the role of Kir in the regulation of vascular tone is not known. Hypothesis: Kir channels play a key role in FIV. Methods: FIV was assessed in mouse mesenteric arteries isolated from wild type (WT) and Kir2.1+/- heterozygous mice. Briefly, resistance arteries were isolated, cannulated and pressurized in an organ chamber with glass micropipettes. Preparations were visualized in real time and the inner diameter of the vessels was measured using acquired images. Kir channels in arteries isolated from WT mice were downregulated by a dominant-negative subunit of Kir2.1 or blocked by Ba2+. The role of Kir channels in flow-induced release of NO was tested by Diaminorhodamine-4M, NO specific fluorescence d...