Signal pathways coupled to activation of neuronal nitric oxide synthase in the spinal cord by nociceptin/orphanin FQ
Signal pathways coupled to activation of neuronal nitric oxide synthase in the spinal cord by nociceptin/orphanin FQ
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DOI：
10.1016/j.neuropharm.2007.01.013
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发表时间：
2007-04
影响因子：
4.7
通讯作者：
Li Xu;E. Okuda‐Ashitaka;S. Matsumura;T. Mabuchi;Shindo Okamoto;K. Sakimura;M. Mishina;S. Ito
中科院分区：
文献类型：
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作者：
Li Xu;E. Okuda‐Ashitaka;S. Matsumura;T. Mabuchi;Shindo Okamoto;K. Sakimura;M. Mishina;S. Ito
伤害感受肽/孤啡肽 FQ (N/OFQ) 较早被证明通过激活神经元一氧化氮合酶 (nNOS) 参与维持神经性疼痛。我们最近建立了一个离体系统，通过结合使用分离的完整脊髓制剂和 NADPH-心肌黄酶组织化学来阐明 nNOS 激活的生化和分子机制。在这里，我们通过使用这种离体系统检查了与脊髓中 nNOS 激活耦合的 N/OFQ 信号通路。根据 NADPH-心肌黄酶组织化学的评估，N/OFQ 以时间和剂量依赖性方式增强脊髓表层的 nNOS 活性。在 3–10 nM 时观察到最大效果。 N/OFQ 刺激的 nNOS 活性被 NMDA 受体拮抗剂 MK-801 和 d-AP5 抑制，但不被 NR2B 选择性拮抗剂 CP-101,606 抑制；在 NR2D−/− 小鼠中观察到刺激的活动，但在 NR2A−/− 或 NR2A−/−/NR2D−/− 小鼠中未观察到。 N/OFQ 受体拮抗剂可减弱 N/OFQ 刺激的 nNOS 活性，但不会减弱 NMDA 刺激的 nNOS 活性。此外，N/OFQ 对 nNOS 的增强作用被钙磷蛋白 C 和 Ro 31-8220、PP2 和 KN-62 抑制，但不被 H-89 抑制。这些结果表明，N/OFQ 通过包含 NR2A 的 NMDA 受体激活引发的生化级联刺激 nNOS 活性。
Nociceptin/orphanin FQ (N/OFQ) was earlier shown to be involved in the maintenance of neuropathic pain by activating neuronal nitric oxide synthase (nNOS). We recently established an ex vivo system to elucidate biochemical and molecular mechanisms for nNOS activation by the use of a combination of isolated intact spinal cord preparations and NADPH-diaphorase histochemistry. Here we examined the N/OFQ signal pathways coupled to nNOS activation in the spinal cord by using this ex vivo system. N/OFQ enhanced nNOS activity in the superficial layer of the spinal cord, as assessed by NADPH-diaphorase histochemistry, in a time- and dose-dependent manner. The maximum effect was observed at 3–10 nM. The N/OFQ-stimulated nNOS activity was inhibited by NMDA receptor antagonists MK-801 and d-AP5, but not by the NR2B-selective antagonist CP-101,606; and the stimulated activity was observed in NR2D−/−mice, but not in NR2A−/−or NR2A−/−/NR2D−/−mice. N/OFQ receptor antagonists attenuated the nNOS activity stimulated by N/OFQ, but not that by NMDA. Furthermore, the potentiation of nNOS by N/OFQ was inhibited by calphostin C and Ro 31–8220, PP2, and KN-62, but not by H-89. These results suggest that N/OFQ stimulated nNOS activity by a biochemical cascade initiated by activation of NMDA receptors containing NR2A.