Protein kinase A-dependent neuronal nitric oxide synthase activation mediates the enhancement of baroreflex response by adrenomedullin in the nucleus tractus solitarii of rats.
Protein kinase A-dependent neuronal nitric oxide synthase activation mediates the enhancement of baroreflex response by adrenomedullin in the nucleus tractus solitarii of rats.
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蛋白激酶A依赖性神经元一氧化氮合酶激活介导大鼠孤束核中肾上腺髓质素增强压力反射反应。
DOI：
10.1186/1423-0127-18-32
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发表时间：
2011-05-19
影响因子：
11
通讯作者：
Yen JC
中科院分区：
文献类型：
--
作者：
Yen DH;Chen LC;Shen YC;Chiu YC;Ho IC;Lou YJ;Chen IC;Yen JC
肾上腺髓质素 (ADM) 通过受体介导的酶机制发挥其生物学功能，其中涉及蛋白激酶 A (PKA) 或神经元一氧化氮合酶 (nNOS)。我们之前证明受体介导的 cAMP/PKA 通路参与 ADM 增强的压力感受器反射 (BRR) 反应。目前尚不清楚 ADM 是否可以通过激活孤束核 (NTS) 中的 nNOS 依赖性机制来增强 BRR 反应。在将测试药物显微注射到 Sprague-Dawley 大鼠的 NTS 中之前和之后 10、30 和 60 分钟，静脉注射去氧肾上腺素以诱发 BRR。使用蛋白质印迹分析来测量 NTS 中参与 ADM (0.2 pmol) 的 BRR 增强作用的蛋白质的水平和磷酸化。通过免疫组织化学染色和激光共聚焦显微镜观察 PKA 和 nNOS 的共定位。我们发现，ADM 诱导的 BRR 反应增强可通过将 NPLA 或 Rp-8-Br-cGMP（分别是 nNOS 或蛋白激酶 G (PKG) 的选择性抑制剂）显微注射到 NTS 中而减弱。蛋白质印迹分析进一步表明，ADM 诱导 PKG-I 蛋白水平增加，这种增加可以通过与 ADM 受体拮抗剂 ADM22-52 或 NPLA 共显微注射来减弱。此外，我们观察到 NTS 内施用 ADM 后 10、30 和 60 分钟，nNOS Ser1416 磷酸化增加。因此，nNOS/PKG 信号传导也可以解释 ADM 对 BRR 反应的增强作用。有趣的是，生化证据进一步表明，与 PKA 抑制剂 Rp-8-Br-cAMP 共显微注射可以阻止 ADM 诱导的 nNOS 磷酸化增加。通过免疫组织化学证明 PKA 和 nNOS 在假定的 NTS 神经元中的共定位，证实了 PKA 依赖性 nNOS 激活的可能性。本研究的新发现是，NTS 中 ADM 增强 BRR 反应的信号转导级联依次由 cAMP/PKA 和 nNOS/PKG 通路组成。
Adrenomedullin (ADM) exerts its biological functions through the receptor-mediated enzymatic mechanisms that involve protein kinase A (PKA), or neuronal nitric oxide synthase (nNOS). We previously demonstrated that the receptor-mediated cAMP/PKA pathway involves in ADM-enhanced baroreceptor reflex (BRR) response. It remains unclear whether ADM may enhance BRR response via activation of nNOS-dependent mechanism in the nucleus tractus solitarii (NTS). Intravenous injection of phenylephrine was administered to evoke the BRR before and at 10, 30, and 60 min after microinjection of the test agents into NTS of Sprague-Dawley rats. Western blotting analysis was used to measure the level and phosphorylation of proteins that involved in BRR-enhancing effects of ADM (0.2 pmol) in NTS. The colocalization of PKA and nNOS was examined by immunohistochemical staining and observed with a laser confocal microscope. We found that ADM-induced enhancement of BRR response was blunted by microinjection of NPLA or Rp-8-Br-cGMP, a selective inhibitor of nNOS or protein kinase G (PKG) respectively, into NTS. Western blot analysis further revealed that ADM induced an increase in the protein level of PKG-I which could be attenuated by co-microinjection with the ADM receptor antagonist ADM22-52 or NPLA. Moreover, we observed an increase in phosphorylation at Ser1416 of nNOS at 10, 30, and 60 min after intra-NTS administration of ADM. As such, nNOS/PKG signaling may also account for the enhancing effect of ADM on BRR response. Interestingly, biochemical evidence further showed that ADM-induced increase of nNOS phosphorylation was prevented by co-microinjection with Rp-8-Br-cAMP, a PKA inhibitor. The possibility of PKA-dependent nNOS activation was substantiated by immunohistochemical demonstration of co-localization of PKA and nNOS in putative NTS neurons. The novel finding of this study is that the signal transduction cascade that underlies the enhancement of BRR response by ADM in NTS is composed sequentially of cAMP/PKA and nNOS/PKG pathways.
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影响因子：
4.8
作者：
Hayashi, Y;Nishio, M;Watanabe, Y
通讯作者：
Watanabe, Y
影响因子：
4.9
作者：
Pontieri, V;Venezuela, MK;Michelini, LC
通讯作者：
Michelini, LC
影响因子：
2.9
作者：
Lin, L. H.;Taktakishvili, O.;Talman, W. T.
通讯作者：
Talman, W. T.
影响因子：
4.7
作者：
Ho, L. K.;Chen, K.;Yen, J. C.
通讯作者：
Yen, J. C.
影响因子：
8.3
作者：
Matsumura, K;Abe, I;Fujishima, M
通讯作者：
Fujishima, M