Nitric oxide increases the activity of the apical 70-pS K+ channel in TAL of rat kidney.
Nitric oxide increases the activity of the apical 70-pS K+ channel in TAL of rat kidney.
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DOI：
10.1152/ajprenal.1998.274.5.f946
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发表时间：
1998-05
期刊：
影响因子：
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通讯作者：
Ming Lu;Xiaohong Wang;Wen‐Hui Wang
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文献类型：
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作者：
Ming Lu;Xiaohong Wang;Wen‐Hui Wang
我们之前已经证明，一氧化氮（NO）介导了血管紧张素II对大鼠肾脏亨利氏袢粗升支（TAL）顶端70-pS K+通道的刺激作用（12）。本实验采用膜片钳技术研究了NO对70 pS钾通道的作用。加入10 μM的S-亚硝基-N-乙酰青霉胺（SNAP），一种NO供体，增加了细胞贴附贴片的通道活性。与此相反，应用100 μM N ω-硝基-L-精氨酸甲酯（l-NAME），一氧化氮合酶（NOS）抑制剂，通道活性降低75 ± 7%。L-NAME的作用是抑制NOS的结果，因为不阻断NOS活性的d-NAME对通道活性没有影响。此外，1 mM L-精氨酸或加入10 μM SNAP可消除1-NAME的作用，进一步支持NO的作用。最后，加入8-溴鸟苷3 '，5'-环一磷酸（8-BrcGMP）也可逆转1-NAME诱导的抑制作用。通过抑制鸟苷酸环化酶消除SNAP的作用的实验也表明，NO的作用是由cGMP依赖性途径介导的。最后，用ELISA测量，10 μM SNAP显著增加髓TAL的cGMP浓度，从12.4 fM/μ g蛋白增加到38.9 fM/μg蛋白。我们的结论是，NO参与调节活性的顶端70 pS K+通道在TAL的大鼠肾脏。
We have previously shown that nitric oxide (NO) mediates the stimulatory effect of angiotensin II on the apical 70-pS K+ channel in the thick ascending limb (TAL) of Henle's loop of the rat kidney (12). In the present study, we used the patch-clamp technique to examine the effects of NO on the 70-pS K+ channel. Addition of 10 μM S-nitroso- N-acetylpenicillamine (SNAP), a NO donor, increased the channel activity in cell-attached patches. In contrast, application of 100 μM N ω-nitro-l-arginine methyl ester (l-NAME), an inhibitor of nitric oxide synthase (NOS), reduced the channel activity by 75 ± 7%. The effect of l-NAME was the result of inhibiting NOS, since d-NAME, which does not block NOS activity, had no effect on the channel activity. In addition, the effect ofl-NAME was abolished in the presence of 1 mM l-arginine or by addition of 10 μM SNAP, further supporting the role of NO. Finally, the l-NAME-induced inhibition was also reversed by adding 8-bromoguanosine 3',5'-cyclic monophosphate (8-BrcGMP). That the effect of NO is mediated by the cGMP-dependent pathway is also suggested by experiments in which inhibition of guanylate cyclase abolished the effect of SNAP. Finally, 10 μM SNAP significantly increased cGMP concentration of the medullary TAL from 12.4 fM/μg protein to 38.9 fM/μg protein, as measured with ELISA. We conclude that NO is involved in regulating the activity of the apical 70-pS K+ channel in the TAL of the rat kidney.