Gγ7 proteins contribute to coupling of nociceptin/orphanin FQ peptide (NOP) opioid receptors and voltage-gated Ca(2+) channels in rat stellate ganglion neurons.
Gγ7 proteins contribute to coupling of nociceptin/orphanin FQ peptide (NOP) opioid receptors and voltage-gated Ca(2+) channels in rat stellate ganglion neurons.
复制标题
Gγ7 蛋白有助于耦合伤害感受肽/孤啡肽 FQ 肽 (NOP) 阿片受体和电压门控 Ca(2 ) 通道在大鼠星状神经节神经元中。
DOI：
10.1016/j.neulet.2016.05.055
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发表时间：
2016
影响因子：
2.5
通讯作者：
Ruiz-Velasco,Victor
中科院分区：
文献类型：
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作者：
Mahmoud,Saifeldin;Farrag,Mohamed;Ruiz-Velasco,Victor
伤害素/孤儿FQ肽(NOP)阿片受体通过抑制交感和感觉神经元的电压门控钙通道(Cav2.2)来调节神经递质的释放。一氧化氮合酶受体被其内源性激动剂伤害性感觉(Noc)刺激，导致由Gβγ蛋白亚基介导的膜分隔的、电压依赖的(Vd)阻断Cav2.2通道电流。我们以前报道过，百日咳毒素敏感的GαI1和Gβ2/β4亚型介导了星状神经节(SG)交感神经元中NOP阿片受体与CaV通道的功能性偶联。在本报告中，我们通过鉴定在该信号通路中形成异三聚体的Gγ亚单位来扩展我们的研究。使用小干扰RNA(或siRNA)来沉默自然表达的Gγ亚单位的表达。初步聚合酶链式反应显示，SG神经元表达7个G-γ亚单位。沉默GNOP3亚基不改变γ受体和钙通道之间的信号转导。然而，沉默Gγ7亚型后，Noc介导的对CaV通道的抑制作用明显低于转染了干扰siRNAs的SG神经元。我们观察到，在Gγ7亚单位沉默后，Gγ10和Gγ11mRNA水平分别增加了2.5倍和2.7倍。然而，这种mRNA表达的代偿性增加似乎并不能完全挽救NOP受体的偶联效率。此外，G-γ-2和G-γ-5的表达水平分别增加了50%和75%，而G-γ-3和G-γ-4的表达水平相对保持不变。综上所述，我们的研究结果表明，GαI1/Gβ2(β4)/Gγ7异源三聚体G蛋白复合体决定了一氧化氮合酶受体介导的脑海绵状核神经元CaV通道的调节。
The nociceptin/orphanin FQ peptide (NOP) opioid receptors regulate neurotransmitter release via inhibition of voltage-gated Ca2+channels (CaV2.2) in sympathetic and sensory neurons. Stimulation of NOP receptors by its endogenous agonist, nociception (Noc), leads to membrane-delimited, voltage-dependent (VD) block of CaV2.2 channel currents mediated by Gβγ protein subunits. Previously we reported that the pertussis toxin-sensitive Gαi1 and Gβ2/β4 isoforms mediate the functional coupling of NOP opioid receptors with CaVchannels in rat stellate ganglion (SG) sympathetic neurons. In the present report we extended our studies by identifying the Gγ subunit that forms the heterotrimer within this signaling pathway. Small interference RNA (or siRNA) was employed to silence the expression of the natively expressed Gγ subunits. Initial PCR assays indicated that SG neurons expressed seven Gγ subunits. Silencing Gγ3 subunits did not alter signaling between NOP receptors and Ca2+channels. However, after Gγ7 isoforms were silenced, the Noc-mediated inhibition of CaVchannels was significantly decreased when compared to SG neurons transfected with scrambled siRNA. We observed that Gγ10 and Gγ11 mRNA levels increased 2.5- and 2.7-fold, respectively, after Gγ7 subunits were silenced. However, this compensatory increase in mRNA expression did not appear to fully rescue the NOP receptor coupling efficiency. Additionally, both Gγ2 and Gγ5 levels increased 50 and 75%, respectively, while Gγ3 and Gγ4 expression levels remained relatively unchanged. Taken together, our findings suggest that the Gαi1/Gβ2(β4)/Gγ7 heterotrimeric G protein complex determines the NOP receptor-mediated modulation of CaVchannels in SG neurons.