Evaluation of ADMA-DDAH-NOS axis in specific brain areas following nitroglycerin administration: study in an animal model of migraine.
Evaluation of ADMA-DDAH-NOS axis in specific brain areas following nitroglycerin administration: study in an animal model of migraine.
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硝酸甘油给药后特定大脑区域中ADMA-DDAH-NOS轴的评估：在偏头痛动物模型中进行研究。
DOI：
10.1186/s10194-015-0560-2
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
Tassorelli C
中科院分区：
文献类型：
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作者：
Greco R;Ferrigno A;Demartini C;Zanaboni A;Mangione AS;Blandini F;Nappi G;Vairetti M;Tassorelli C
已知一氧化氮（NO）在偏头痛发病机制中起关键作用，但迄今为止NO合成的调节在偏头痛治疗中未能显示功效。不对称二甲基精氨酸（ADMA）是一种NO合酶（NOS）抑制剂，其水平受二甲基精氨酸二甲氨基水解酶（DDAH）调节。硝酸甘油（或三硝酸甘油，GTN）的全身给药是一个NO供体，始终诱导自发性头痛发作的偏头痛。GTN给药诱导神经元NOS（nNOS）的增加，这是同时与痛觉过敏的条件。GTN给药多年来一直被用作偏头痛的实验动物模型。为了进一步了解NO合成与偏头痛之间关系的确切机制，我们分析了GTN给药引起的ADMA水平、DDHA-1 mRNA表达以及脑中神经元和内皮NOS（nNOS和eNOS）表达的变化。我们还评估了血清中的ADMA水平。将雄性Sprague-Dawley大鼠用GTN（10 mg/kg，i. p.）或溶媒，4小时后处死。解剖出已知被GTN施用激活的脑区域，并通过蛋白质印迹法用于评估nNOS和eNOS表达。通过ELISA免疫测定法测量脑和血清ADMA水平。采用RT-PCR方法检测脑DDAH-1 mRNA表达。使用Mann Whitney检验进行实验组之间的比较。GTN给药后，下丘脑和延髓中ADMA水平和nNOS表达增加。相反，在相同的区域中观察到DDAH-1 mRNA表达的显著降低。相比之下，eNOS表达无显著变化。GTN给药未引起血清ADMA水平的任何显著变化。目前的数据表明，ADMA在GTN给药后通过抑制DDAH-1在脑中蓄积。后者可能是一种补偿性的反应过度的本地可用性NO，直接释放GTN或合成的nNOS。这些发现提示了一种额外的介质（ADMA）在GTN给药后调节NO轴，并为偏头痛的病理生理学提供了新的见解。
Nitric oxide (NO) is known to play a key role in migraine pathogenesis, but modulation of NO synthesis has failed so far to show efficacy in migraine treatment. Asymmetric dimethylarginine (ADMA) is a NO synthase (NOS) inhibitor, whose levels are regulated by dimethylarginine dimethylaminohydrolase (DDAH). Systemic administration of nitroglycerin (or glyceryl trinitrate, GTN) is a NO donor that consistently induces spontaneous-like headache attacks in migraneurs. GTN administration induces an increase in neuronal NOS (nNOS) that is simultaneous with a hyperalgesic condition. GTN administration has been used for years as an experimental animal model of migraine. In order to gain further insights in the precise mechanisms involved in the relationships between NO synthesis and migraine, we analyzed changes induced by GTN administration in ADMA levels, DDHA-1 mRNA expression and the expression of neuronal and endothelial NOS (nNOS and eNOS) in the brain. We also evaluated ADMA levels in the serum. Male Sprague–Dawley rats were injected with GTN (10 mg/kg, i.p.) or vehicle and sacrificed 4 h later. Brain areas known to be activated by GTN administration were dissected out and utilized for the evaluation of nNOS and eNOS expression by means of western blotting. Cerebral and serum ADMA levels were measured by means of ELISA immunoassay. Cerebral DDAH-1 mRNA expression was measured by means of RT-PCR. Comparisons between experimental groups were performed using the Mann Whitney test. ADMA levels and nNOS expression increased in the hypothalamus and medulla following GTN administration. Conversely, a significant decrease in DDAH-1 mRNA expression was observed in the same areas. By contrast, no significant change was reported in eNOS expression. GTN administration did not induce any significant change in serum levels of ADMA. The present data suggest that ADMA accumulates in the brain after GTN administration via the inhibition of DDAH-1. This latter may represent a compensatory response to the excessive local availability of NO, released directly by GTN or synthetized by nNOS. These findings prompt an additional mediator (ADMA) in the modulation of NO axis following GTN administration and offer new insights in the pathophysiology of migraine.