一氧化氮合酶抑制作用会改变大鼠局灶性脑缺血中的脑血流量和氧平衡。

Wei H M, Chi O Z, Liu X, Sinha A K, Weiss H R

Department of Anesthesiology, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854-5635.

Stroke. 1994 Feb;25(2):445-9; discussion 449-50. doi: 10.1161/01.str.25.2.445.

BACKGROUND AND PURPOSE

This study investigated whether the nitric oxide synthase inhibitor NG-nitro-L-arginine-methyl ester (L-NAME) would alter blood flow and oxygen balance in the ischemic cerebrocortex of isoflurane-anesthetized Long-Evans rats.

METHODS

Fifteen minutes after middle cerebral artery occlusion, L-NAME (1.5 mg/min per kilogram) was infused intravenously to the L-NAME group (n = 14), and normal saline was given to the control group (n = 14) for 45 minutes. In each group, regional cerebral blood flow was determined with [14C]iodoantipyrine, and arterial and venous oxygen saturations were determined by microspectrophotometry.

RESULTS

In both groups regional cerebral blood flow of the ischemic cortex was significantly lower than that of the contralateral cortex ([mean +/- SD] 55 +/- 13 versus 110 +/- 29 mL/min per 100 g in the control group and 35 +/- 13 versus 90 +/- 24 mL/min per 100 g in the L-NAME group). Compared with the blood flow in the ischemic cortex of the control group, L-NAME significantly reduced ischemic blood flow by 36%. Venous oxygen saturation was significantly increased in the ischemic cortex (41 +/- 1% versus 44 +/- 3%) but decreased in the contralateral cortex (65 +/- 3% versus 61 +/- 4%) by L-NAME. Calculated ischemic cortical oxygen consumption in the L-NAME group was 39% lower than that in the corresponding control group, whereas the difference was only 11% in the contralateral sides between groups. In both groups, the ratio of oxygen supply to consumption was lower in the ischemic than in the nonischemic regions. In the ischemic cortex, this ratio was significantly lower in the control group than in the L-NAME group (1.7 +/- 0.1 versus 1.9 +/- 0.1). In contrast, the ratio tended to be decreased by L-NAME in nonischemic regions.

CONCLUSIONS

These observations suggest that despite a decrease in cerebral blood flow, inhibition of nitric oxide synthesis mildly improves the oxygen supply and consumption balance in the ischemic cortex.

背景与目的

本研究调查了一氧化氮合酶抑制剂NG-硝基-L-精氨酸甲酯（L-NAME）是否会改变异氟烷麻醉的Long-Evans大鼠缺血性大脑皮质的血流和氧平衡。

方法

大脑中动脉闭塞15分钟后，向L-NAME组（n = 14）静脉输注L-NAME（1.5毫克/分钟/千克），向对照组（n = 14）输注生理盐水，持续45分钟。每组均用[14C]碘安替比林测定局部脑血流量，并用显微分光光度法测定动脉和静脉血氧饱和度。

结果

两组缺血皮质的局部脑血流量均显著低于对侧皮质（对照组：[均值±标准差]55±13对110±29毫升/分钟/100克，L-NAME组：35±13对90±24毫升/分钟/100克）。与对照组缺血皮质的血流相比，L-NAME使缺血血流显著减少了36%。L-NAME使缺血皮质的静脉血氧饱和度显著升高（41±1%对44±3%），但使对侧皮质的静脉血氧饱和度降低（65±3%对61±4%）。L-NAME组计算得出的缺血皮质氧消耗量比相应对照组低39%，而两组对侧之间的差异仅为11%。两组中，缺血区域的氧供与氧耗比均低于非缺血区域。在缺血皮质中，对照组的该比值显著低于L-NAME组（1.7±0.1对1.9±0.1）。相比之下，L-NAME使非缺血区域的该比值有降低趋势。