Koss M C
Department of Pharmacology, University of Oklahoma, College of Medicine, Oklahoma City 73190, USA.
Invest Ophthalmol Vis Sci. 1998 Mar;39(3):559-64.
The aim of this study was to use laser Doppler flowmetry to measure anterior choroidal blood flow in the anesthetized rat and to determine the role of nitric oxide (NO) in the maintenance of basal ocular blood flow in vivo.
By using laser Doppler flowmetry, blood flow from the anterior choroid in pentobarbital-anesthetized rats was measured continuously. Graded single doses (0.03-300 mg/kg) of the nonselective NO synthase inhibitor NG-nitro-L-arginine-methyl ester (L-NAME) were administered intravenously to establish dose-response relationships. Other groups of animals were tested with L-NAME after the prior administration of L-arginine, with D-NAME, or with the selective neural NO synthase inhibitor 7-nitroindazole.
Intravenous administration of L-NAME produced a dose-related depression of anterior choroidal blood flow in the 0.3- to 30-mg/kg range. Maximal depression of approximately 60% occurred at the 30-mg/kg dose, peaked at approximately 30 minutes, and lasted throughout the 60-minute experimental period. At 10 mg/kg, L-NAME reduced ocular blood flow by approximately 50%, an effect that was abolished by pretreatment with intravenous L-arginine (300 mg/kg). Both D-NAME (10 mg/kg, intravenously) and 7-nitroindazole (50 mg/kg, intraperitoneally) were inactive with regard to ocular blood flow depression.
Laser Doppler flowmetry appears to be a useful tool for continuous, online measurement of anterior choroidal blood flow in the rat eye. Results with L-NAME and 7-nitroindazole suggest that local tonic generation of endothelial NO plays an important role in the maintenance of basal anterior choroidal blood flow in this species.
本研究旨在使用激光多普勒血流仪测量麻醉大鼠脉络膜前部的血流，并确定一氧化氮（NO）在体内维持基础眼血流中的作用。
使用激光多普勒血流仪，连续测量戊巴比妥麻醉大鼠脉络膜前部的血流。静脉注射不同剂量（0.03 - 300 mg/kg）的非选择性NO合酶抑制剂NG-硝基-L-精氨酸甲酯（L-NAME），以建立剂量反应关系。其他几组动物在预先给予L-精氨酸、D-NAME或选择性神经NO合酶抑制剂7-硝基吲唑后，再用L-NAME进行测试。
静脉注射L-NAME在0.3至30 mg/kg范围内可使脉络膜前部血流产生剂量相关的降低。在30 mg/kg剂量时，最大降低约60%，在约30分钟时达到峰值，并在整个60分钟的实验期内持续存在。在10 mg/kg时，L-NAME使眼血流减少约50%，静脉注射L-精氨酸（300 mg/kg）预处理可消除该效应。D-NAME（静脉注射10 mg/kg）和7-硝基吲唑（腹腔注射50 mg/kg）对眼血流降低均无作用。
激光多普勒血流仪似乎是连续在线测量大鼠眼脉络膜前部血流的有用工具。L-NAME和7-硝基吲唑的结果表明，内皮源性NO的局部张力生成在维持该物种基础脉络膜前部血流中起重要作用。
