H2O2 is the transferrable factor mediating flow-induced dilation in human coronary arterioles. Circ Res 2011 Mar 04;108(5):566-73
Date
01/15/2011Pubmed ID
21233456Pubmed Central ID
PMC3108183DOI
10.1161/CIRCRESAHA.110.237636Scopus ID
2-s2.0-79952751560 (requires institutional sign-in at Scopus site) 146 CitationsAbstract
RATIONALE: Endothelial derived hydrogen peroxide (H(2)O(2)) is a necessary component of the pathway regulating flow-mediated dilation (FMD) in human coronary arterioles (HCAs). However, H(2)O(2) has never been shown to be the endothelium-dependent transferrable hyperpolarization factor (EDHF) in response to shear stress.
OBJECTIVE: We examined the hypothesis that H(2)O(2) serves as the EDHF in HCAs to shear stress.
METHODS AND RESULTS: Two HCAs were cannulated in series (a donor intact vessel upstream and endothelium-denuded detector vessel downstream). Diameter changes to flow were examined in the absence and presence of polyethylene glycol catalase (PEG-CAT). The open state probability of large conductance Ca(2+)-activated K(+) (BK(Ca)) channels in smooth muscle cells downstream from the perfusate from an endothelium-intact arteriole was examined by patch clamping. In some experiments, a cyanogen bromide-activated resin column bound with CAT was used to remove H(2)O(2) from the donor vessel. When flow proceeds from donor to detector, both vessels dilate (donor:68±7%; detector: 45±11%). With flow in the opposite direction, only the donor vessel dilates. PEG-CAT contacting only the detector vessel blocked FMD in that vessel (6±4%) but not in donor vessel (61±13%). Paxilline inhibited dilation of endothelium-denuded HCAs to H(2)O(2). Effluent from donor vessels elicited K(+) channel opening in an iberiotoxin- or PEG-CAT-sensitive fashion in cell-attached patches but had little effect on channel opening on inside-out patches. Vasodilation of detector vessels was diminished when exposed to effluent from CAT-column.
CONCLUSIONS: Flow induced endothelial production of H(2)O(2), which acts as the transferrable EDHF activating BK(Ca) channels on the smooth muscle cells.
Author List
Liu Y, Bubolz AH, Mendoza S, Zhang DX, Gutterman DDAuthor
David X. Zhang MD, PhD Associate Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
ArteriolesBiological Factors
Catalase
Coronary Vessels
Endothelium, Vascular
Humans
Hydrogen Peroxide
Indoles
Large-Conductance Calcium-Activated Potassium Channels
Muscle, Smooth, Vascular
Patch-Clamp Techniques
Polyethylene Glycols
Potassium Channel Blockers
Regional Blood Flow
Vasodilation