Differential effects of short-term hypoxia and hypercapnia on N-methyl-D-aspartate-induced cerebral vasodilatation in piglets
Differential effects of short-term hypoxia and hypercapnia on N-methyl-D-aspartate-induced cerebral vasodilatation in piglets
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DOI：
10.1161/01.str.27.9.1634
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发表时间：
1996-09-01
期刊：
影响因子：
8.3
通讯作者：
Busija, DW
中科院分区：
文献类型：
--
作者：
Bari, F;Errico, RA;Busija, DW
背景和目的近年来对仔猪的研究表明，无论是窒息还是全脑缺血，其结合了缺氧和高碳酸血症的影响，都能短暂地减弱N-甲基-D-天冬氨酸（NMDA）诱导的软膜小动脉扩张。本研究的目的是分别确定缺氧和常氧高碳酸血症对NMDA依赖性脑血管反应性的影响。此外，我们研究机制参与减少脑血管扩张NMDA.Methods在麻醉小猪，我们研究软脑膜小动脉直径使用颅窗和活体显微镜。在对照条件下和动脉缺氧或动脉高碳酸血症后测定局部应用NMDA的小动脉反应。此外，在给予吲哚美辛的动物中检查了小动脉对NMDA的反应（10 mg/kg IV）或超氧化物歧化酶结果在对照组条件下，应用NMDA可使软膜小动脉呈剂量依赖性扩张（例如，低氧组NMDA分别高于基线水平9+/-1%至10（-5）、15+/-2%至5x 10（-5）和28+/-5%至10（-4）mol/L; n=6，P
Background and Purpose Recent studies in piglets show that either asphyxia or global cerebral ischemia, which combines effects of hypoxia and hypercapnia, transiently attenuates N-methyl-D-aspartate (NMDA)-induced pial arteriolar dilation. The purpose of this study was to determine individually the effects of hypoxic hypoxia and normoxic hypercapnia on NMDA-dependent cerebrovascular reactivity. In addition, we examined mechanisms involved in reduced cerebral vascular dilation to NMDA.Methods In anesthetized piglets, we examined pial arteriolar diameters using a cranial window and intravital microscopy. Arteriolar responses to topically applied NMDA were determined under control conditions and after arterial hypoxia or arterial hypercapnia. In addition, arteriolar responses to NMDA were examined in animals given indomethacin (10 mg/kg IV) or superoxide dismutase (100 U/mL, topical application) before hypoxia.Results Under control conditions, application of NMDA produced a dose-related dilation of pial arterioles (eg, 9+/-1% to 10(-5) 15+/-2% to 5x10(-5), and 28+/-5% to 10(-4) mol/L NMDA above baseline, respectively, in the hypoxic group; n=6, P