کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4011282 1602619 2012 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Retinal arteriolar responses to acute severe elevation in systemic blood pressure in cats: Role of endothelium-derived factors
موضوعات مرتبط
علوم زیستی و بیوفناوری ایمنی شناسی و میکروب شناسی ایمونولوژی و میکروب شناسی (عمومی)
پیش نمایش صفحه اول مقاله
Retinal arteriolar responses to acute severe elevation in systemic blood pressure in cats: Role of endothelium-derived factors
چکیده انگلیسی

The purpose of this study was to investigate the roles of endothelium-derived factors in the retinal arteriolar responses to acute severe elevation in systemic blood pressure (BP) in cats. Acute elevation of mean arterial BP by 60% for 5 min was achieved by inflating a balloon-tipped catheter in the descending aorta. The retinal arteriolar diameter, flow velocity, wall shear rate (WSR) and blood flow (RBF) changes during BP elevation were assessed with laser Doppler velocimetry 2 h after intravitreal injections of nitric oxide (NO) synthase inhibitor l-NAME, cyclooxygenase inhibitor indomethacin, endothelin-1 receptor antagonists (BQ-123 for type A and BQ-788 for type B), or Rho kinase inhibitor fasudil. BP elevation caused a marked increase in retinal arteriolar flow velocity and WSR with slight vasoconstriction, resulting in an increase in RBF. The increases in velocity, WSR and RBF, but not diameter, were correlated with the increase in ocular perfusion pressure. With l-NAME or indomethacin, the increase in RBF upon BP elevation was significantly attenuated due to enhanced retinal arteriolar vasoconstriction. In contrast, BQ-123 and fasudil potentiated the increased RBF. BQ-788 had no effect on arteriolar diameter and hemodynamics. Our data suggest that acute elevation of BP by 60% leads to an increase in RBF due to the release of NO and prostanoids probably through a shear stress-induced vasodilation mechanism. The release of endothelin-1 and Rho kinase activation help to limit RBF augmentation by counteracting the vasodilation. It appears that the retinal endothelium, by releasing vasoactive substances, contributes to RBF regulation during acute severe elevation of systemic blood pressure.


► We measured retinal blood flow in cats with raised systemic blood pressure.
► Retinal blood flow increased during acute severe elevation of blood pressure.
► Nitric oxide and prostanoids play a role in increasing retinal blood flow.
► Endothelin-1 and Rho kinase play a role in attenuating retinal blood flow.
► Retinal endothelium may contribute to retinal blood flow regulation.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Experimental Eye Research - Volume 103, October 2012, Pages 63–70
نویسندگان
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