Nitric oxide in renal cortex and medulla. An in vivo microdialysis study.
Nitric oxide in renal cortex and medulla. An in vivo microdialysis study.
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肾皮质和髓质中的一氧化氮。
DOI：
10.1161/01.hyp.29.1.194
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
CowleyJr,AW
中科院分区：
文献类型：
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作者：
Zou,AP;CowleyJr,AW
本研究通过体内微透析技术检测了肾皮质和髓质中一氧化氮（NO）的产生。通过透析系统灌注浓度为3 μmol/L的氧合血红蛋白（OxyHb），捕获组织NO。在401 nm处分光光度法测定透析液中氧血红蛋白氧化生成的高铁血红蛋白（MetHb）。因为氧化hb生成甲基苯丙胺是与NO进行化学计量的，所以NO的生成可以由甲基苯丙胺的生成速率决定。结果显示，髓质NO浓度（57.1±5.57 nmol/L, n=10）显著高于皮质NO浓度（31.2±5.7 nmol/L, n=9），差异有统计学意义（P< 0.05）。本试验的最低检测NO水平为≈10 nmol/L。静脉输注精氨酸（每分钟3mg /kg） 30分钟可使皮质和髓质NO增加2 - 3倍；ng -硝基精氨酸甲酯（L-NAME） （10 μg/kg / min）可使肾皮质一氧化氮降低33%，肾髓质一氧化氮降低46.5%。我们还采用体内微透析结合微量滴度板比色法比较了相同条件下肾皮质和肾髓质的NO、亚硝酸盐和硝酸盐的降解产物。髓质亚硝酸盐/硝酸盐浓度（2.7±0.6 μmol/L, n=4）显著高于皮质亚硝酸盐/硝酸盐浓度（2.1±0.2 μmol/L, n=4） （P< 0.05）。输注精氨酸可使皮质和髓质亚硝酸盐/硝酸盐分别增加65%和39%。L-NAME可使皮质和髓质亚硝酸盐/硝酸盐分别降低18%和23%。结果表明，OxyHb-NO微透析捕获技术是一种高灵敏度的原位检测肾脏组织局部NO浓度和NO合成酶活性变化的方法。这些研究表明，髓质组织中的NO浓度高于皮层。
This study examined the production of nitric oxide (NO) in the renal cortex and medulla through the use of an in vivo microdialysis technique. Oxyhemoglobin (OxyHb) at a concentration of 3 μmol/L was perfused through the dialysis system to trap tissue NO. Methemoglobin (MetHb), which was formed by NO oxidation of OxyHb in the dialysate, was spectrophotometrically assayed at 401 nm. Because the oxidation of OxyHb to produce MetHb is stoichiometric with NO, the production of NO can be determined by the rate of MetHb formation. We found that NO concentration was significantly higher (P<.05) in the medulla (57.1±5.57 nmol/L, n=10) than in the cortex (31.2±5.7 nmol/L, n=9). The minimal detectable NO level of this assay is ≈10 nmol/L. Intravenous infusion ofl-arginine (3 mg/kg per minute) for 30 minutes produced a twofold to threefold increase in cortical and medullary NO; NG-nitro-l-arginine methyl ester (L-NAME) (10 μg/kg per minute) decreased NO by 33% in the renal cortex and by 46.5% in the renal medulla. We have also compared under the same conditions the degradation products of NO, nitrite, and nitrate in the renal cortex and medulla using in vivo microdialysis combined with microtiter plate colorimetry. Nitrite/nitrate concentration was significantly higher (P<.05) in the medulla (2.7±0.6 μmol/L, n=4) than in the cortex (2.1±0.2 μmol/L, n=4). Infusion ofl-arginine increased cortical and medullary nitrite/nitrate by 65% and 39%, respectively. L-NAME reduced cortical and medullary nitrite/nitrate by 18% and 23%, respectively. The results indicate that the OxyHb-NO microdialysis trapping technique is a highly sensitive in situ method for detecting regional tissue NO concentration and changes in the NO synthase activity in the kidney. These studies have shown that NO concentration is higher in medullary tissue than in the cortex.