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Acute high glucose concentration increases myogenic tone in bovine retinal arteries through a protein kinase c mechanism
Author(s) -
Owen Mary Pruitt,
Andrews Jaiye A.,
Zhu Shu,
Barman Scott A.,
White Richard E.
Publication year - 2011
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.25.1_supplement.1021.5
Subject(s) - protein kinase c , retinal , medicine , endocrinology , myogenic contraction , chelerythrine , diabetic retinopathy , retinopathy , retina , chemistry , vascular smooth muscle , diabetes mellitus , biology , kinase , ophthalmology , biochemistry , smooth muscle , neuroscience
A reduction in retinal blood flow is one of the early features of diabetic retinopathy. Hyperglycemia is an important risk factor for vascular complications in diabetes and is believed to modulate protein kinase C (PKC) activation in the retina. The object of this study was to evaluate the effect of acute exposure to high glucose (25 mM) on myogenic tone in the retinal circulation and to determine whether that myogenic tone can be modified by inhibition of PKC. Branches of the retinal artery were removed from the bovine retinal sheath and pressurized using an arteriograph system. At 60, 80 and 100 mm Hg, significantly more tone (4.2 ± 1.4%, 3.5 ± 0.8% and 3.7 ± 1.1%, respectively) developed in high glucose buffer than in normal buffer (5.5 mM). Chelerythrine, a nonselective PKC inhibitor, blocked the effect of high glucose on myogenic tone and reduced the level of myogenic tone in normal glucose. In addition, western blot results showed that isoforms alpha, beta, delta, epsilon, iota and lambda of PKC are expressed in bovine retinal arterial vascular tissue. To our knowledge, this is the first study to show that acute high glucose concentration increases myogenic tone in isolated retinal arteries through a PKC mechanism. Exploitation of a possible PKC isoform specificity for this effect has potential for delaying, stopping or even reversing diabetic retinopathy. (CCDA and HL‐68026)