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Endothelium‐derived reactive oxygen species impair myogenic tone in type‐2 diabetic rat ophthalmic artery
Author(s) -
Jarajapu Yagna PR,
Ito Isamu,
Guberski Dennis,
Grant Maria
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.571.4
Subject(s) - apocynin , nadph oxidase , peroxynitrite , medicine , myogenic contraction , endocrinology , vasodilation , constriction , vasoconstriction , reactive oxygen species , superoxide , nitric oxide , nitric oxide synthase , chemistry , oxidative stress , biochemistry , smooth muscle , enzyme
We have previously reported that myogenic tone in ophthalmic artery is impaired in obese type‐2 diabetic BBZDR/Wor rat. In this study, we delineated the role of endothelium‐derived reactive oxygen species (ROS) in the attenuated myogenic response. Ophthalmic arteries were isolated from BBZDR/Wor rats (T2D) with 4–5 months duration of diabetes and the age‐matched lean non‐diabetic rats (control). Arterial segments were cannulated in an arteriograph and inner diameter was continuously recorded over a range of intraluminal pressures in the presence or absence of different pharmacological agents. Pressure‐induced constriction in T2D artery was significantly lower compared to that control in the range of 50–150 mmHg. Dilation to carbachol or bradykinin was significantly lower and L‐NAME (non‐specific nitric oxide synthase inhibitor)‐mediated constriction was higher in T2D artery compared to the control when studied at an intraluminal pressure of 70 mmHg. In the presence of 4‐aminoguanidine, myogenic tone T2D artery was comparable to that of control over the pressure range of 50–150 mmHg. Similar results were observed when T3D artery was treated with a scavenger of ROS, N‐acetyl cysteine, NADPH oxidase inhibitor apocynin or peroxynitrite scavenger ebselen. These results suggest that peroxynitrite generated from superoxide and NO acts on arterial smooth muscle and antagonizes myogenic tone.