Chatziantoniou C, Pauti M D, Pinet F, Promeneur D, Dussaule J C, Ardaillou R
INSERM U.64, Hôpital Tenon, Paris, France.
Kidney Int. 1996 Mar;49(3):626-33. doi: 10.1038/ki.1996.90.
The aim of the present study was dual: first to establish that a preparation of afferent arterioles freshly isolated from the rat kidney is a suitable model to study renin release and synthesis, and second to investigate the effect(s) of nitric oxide (NO) inhibition on renin release in this model. Purification of renal microvessels was based on iron oxide infusion into the kidneys and separation of the afferent arterioles from glomeruli and connective tissue with a magnet. These microvessels express preprorenin mRNA, contain renin granules and release renin as evidenced by RT-PCR, immunocytochemistry and measurement of renin activity, respectively. Renin secretion was increased in isolated afferent arterioles after in vivo treatment with the diuretic furosemide (+300%) or in vitro treatment with the adenylyl cyclase activator forskolin (+50%), indicating that this vascular preparation responds appropriately to regulators of the renin-angiotensin system. Furthermore, in afferent arterioles isolated from control rats, renin release was positively correlated with total renin content (r = 0.85). In afferent arterioles isolated from rats chronically treated with the NO-synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME), forskolin was ineffective in modifying renin release despite stimulation of cAMP levels. In addition, the correlation between renin release and tissue renin content was disrupted. Similar results were obtained when cortical slices were used instead of afferent arterioles, suggesting that this defect in the regulation of renin release is independent of the presence of macula densa cells. To verify that the lack of regulation of renin release after L-NAME treatment was due to NO inhibition, the NO donor 3-morpholino-syndonimin-hydrochloride (SIN-1) was administered in afferent arterioles or cortical slices from kidneys of L-NAME-treated rats. In both preparations, SIN-1 reversed the L-NAME effect and re-established the responsiveness of renin release to forskolin and the relationship between renin release and renin content. These data indicate that the adenylyl cyclase-mediated mechanism regulating renin release is impaired when NO synthesis is inhibited.
其一，证实从大鼠肾脏新鲜分离的传入小动脉制剂是研究肾素释放和合成的合适模型；其二，在该模型中研究一氧化氮（NO）抑制对肾素释放的影响。肾微血管的纯化基于向肾脏注入氧化铁，并通过磁体从肾小球和结缔组织中分离出传入小动脉。这些微血管表达前肾素原mRNA，含有肾素颗粒，并分别通过逆转录聚合酶链反应（RT-PCR）、免疫细胞化学和肾素活性测定证明可释放肾素。用利尿剂呋塞米进行体内治疗（增加300%）或用腺苷酸环化酶激活剂福斯可林进行体外治疗（增加50%）后，分离的传入小动脉中的肾素分泌增加，表明这种血管制剂对肾素-血管紧张素系统的调节剂有适当反应。此外，在从对照大鼠分离的传入小动脉中，肾素释放与总肾素含量呈正相关（r = 0.85）。在从长期用一氧化氮合酶抑制剂N-硝基-L-精氨酸甲酯（L-NAME）治疗的大鼠分离的传入小动脉中，尽管cAMP水平受到刺激，但福斯可林在改变肾素释放方面无效。此外，肾素释放与组织肾素含量之间的相关性被破坏。当使用皮质切片代替传入小动脉时，获得了类似的结果，这表明肾素释放调节中的这种缺陷与致密斑细胞的存在无关。为了验证L-NAME治疗后肾素释放缺乏调节是由于NO抑制所致，将NO供体3-吗啉代-辛多明-盐酸盐（SIN-1）施用于L-NAME治疗大鼠肾脏的传入小动脉或皮质切片中。在这两种制剂中，SIN-1逆转了L-NAME的作用，并重新建立了肾素释放对福斯可林的反应性以及肾素释放与肾素含量之间的关系。这些数据表明，当NO合成受到抑制时，腺苷酸环化酶介导的调节肾素释放的机制受损。
