Previous studies have demonstrated that arachidonic acid (AA) induces potent dilation of human coronary arterioles (HCAs) through the activation of endothelial TRPV4 channels followed by endothelial hyperpolarization or release of vasoactive substances. In addition, TRPV4‐mediated vasodilatory response to flow is augmented in HCAs from subjects with coronary artery disease (CAD), a condition associated with increased H2O2 production. However, the role of H2O2 in regulation of TRPV4 function remains to be elucidated. Therefore, we designed this study to examine the effect of endogenous H2O2 on TRPV4 function. Coronary arterioles (~150 μm ID), isolated from atrial tissues from patients with CAD, were cannulated and pressurized at 60 mmHg for videomicroscopic measurement of vessel diameters. In arterioles preconstricted with endothelin‐1, AA (10−11 to 10−6 M) elicited a concentration‐dependent dilation (maximal dilation: 84±5%, n=5), and this dilation was largely blocked by HC‐067047 (10−6 M), a TRPV4 antagonist (17±4%, n=5). Intraluminal incubation of HCAs with catalase, a H2O2 –scavenging enzyme (500 units/mL), also markedly reduced the dilation to AA (57±5% vs. 85±5% of control, n=8). The EET antagonist 14,15‐EEZE (10−5 M) failed to attenuate AA‐induced dilation (64±6% vs. 70±7% of control, n=5), suggesting that P450 metabolites of AA such as EETs do not significantly contribute to endothelial TRPV4‐mediated response. Together, these data provide evidence that H2O2 regulates AA‐induced TRPV4‐mediated dilation in HCAs.Support or Funding InformationThis work was supported by NIH R01‐HL096647 (to David X Zhang)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.