Flow dependence and time constant of the change in nitric oxide concentration measured in the vascular media
Flow dependence and time constant of the change in nitric oxide concentration measured in the vascular media
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DOI：
10.1007/bf02513336
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发表时间：
1999-07-01
影响因子：
3.2
通讯作者：
Kajiya, F
中科院分区：
文献类型：
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作者：
Mochizuki, S;Goto, M;Kajiya, F
人们一直认为，动脉血管壁上内皮源性一氧化氮（NO）的浓度会随着血流诱导的剪切应力而变化。本研究采用NO敏感电极，目的是直接评价灌注速率与动脉血管壁NO浓度的关系。将直径100 μ m的NO微电极插入离体犬股动脉血管介质中，并用Krebs-Henseleit缓冲液灌注血管。然后通过改变灌注率来评估血管介质中NO浓度的血流相关变化。随着灌注速率的逐步增加，NO浓度在一阶时间延迟后达到峰值，且峰值水平NO浓度与各血管灌注速率呈线性相关（10-154 pA, 2.1-72.3 ml min） （-1）；N = 7, r(2) = 0.89-0.99, p < 0.03)。NO电流随灌注率逐步增加而增加的平均时间常数为24 +/- 3 s （n = 5）。灌注1 mmol l(-1) l -精氨酸溶液后，一氧化氮产量增加，灌注100 μ mol l(-1) n - g -硝基l -精氨酸溶液后，一氧化氮产量减少，表明内皮细胞完整，NO电极插入适当，电极选择性检测NO。由此可见，NO微电极适用于NO控制血管张力的血管介质中NO的测量，且动脉血管介质中NO浓度随灌注速率呈速率依赖性变化，且在流量逐步增加时，其时间常数约为24s。
It has been considered that the concentration of endothelium-derived nitric oxide (NO) in the arterial vascular wall changes in response to flow-induced shear stress. In the present study, using an NO-sensitive electrode, the aim was to directly evaluate the relationship between perfusion rate and NO concentration in the arterial vascular wall. The NO microelectrode (diameter: 100 mu m) was inserted into the vascular media of isolated canine femoral arteries, and the vessel was perfused with a Krebs-Henseleit buffer solution. A flow-related change in NO concentration in the vascular media was then evaluated by changing perfusion rate. NO concentration attained a peak value with a first-order time delay by a stepwise increase in perfusion rate, and the peak-level NO concentration was linearly correlated with perfusion rate in each vessel (10-154 pA at 2.1-72.3 ml min(-1); n = 7, r(2) = 0.89-0.99, p < 0.03). The average time constant for an increase in NO current with a stepwise increase in perfusion rate was 24 +/- 3 s (n = 5). NO production was increased by perfusing a solution containing 1 mmol l(-1) L-arginine and was attenuated by 100 mu mol l(-1) N-G-nitro-L-arginine, indicating the intactness of the endothelium, proper insertion of the NO electrode and selective detection of NO by the electrode. It is concluded that the NO microelectrode is applicable to NO measurement in the vascular media where NO controls vascular tone and that the concentration of NO in the arterial vascular media changes with perfusion rate in a rate-dependent manner as well as with a time constant of about 24s for a stepwise increase in flow.