Striatal Cholinergic Interneurons Display Activity-Related Phosphorylation of Ribosomal Protein S6
Striatal Cholinergic Interneurons Display Activity-Related Phosphorylation of Ribosomal Protein S6
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DOI：
10.1371/journal.pone.0053195
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发表时间：
2012-12-28
期刊：
影响因子：
3.7
通讯作者：
Balleine, Bernard W.
中科院分区：
文献类型：
--
作者：
Bertran-Gonzalez, Jesus;Chieng, Billy C.;Balleine, Bernard W.
胆碱能中间神经元（CINs）为所有纹状体区域提供乙酰胆碱的主要来源，并通过复杂的突触前和突触后乙酰胆碱受体调节多巴胺能作用。虽然纹状体CIN具有明确的电生理特征，但其生化特性知之甚少，可能是由于其在纹状体内的比例较低（2-3%）。我们报告了核糖体蛋白S6在其丝氨酸240和244残基（p-Ser（240-244）-S6 rp）上的强烈和持续的磷酸化，该蛋白是与雷帕霉素复合物1（mTORC 1）通路的哺乳动物靶相关的核糖体机制的蛋白质组成部分，我们发现其主要在基础条件下在纹状体CIN中表达。我们通过在CIN中诱导各种持续的生理活性状态并评估对S6 rp磷酸化水平的影响来探索这种细胞事件的功能相关性。纹状体切片制备的CIN的细胞贴附电生理记录显示，河豚毒素（TTX）对动作电位放电的抑制作用，通过免疫荧光检测到长时间孵育后p-Ser（240-244）-S6 rp信号的减少来实现。另一方面，细胞外钾浓度的升高和添加蜂毒肽分别在CIN中产生增加的放电速率和爆发放电活性，并且当孵育1小时时，两种刺激条件均显著增加Ser（240-244）-S6 rp磷酸化高于基础水平。Apamin产生了对雷帕霉素敏感的磷酸化的特别大的增加。两者合计，我们的研究结果表明，第一次之间的联系，神经元活动的状态和纹状体CINs的生化信号事件，并表明免疫荧光可用于估计不同的药理学和/或行为条件下的CINs的细胞活性。
Cholinergic interneurons (CINs) provide the main source of acetylcholine to all striatal regions, and strongly modulate dopaminergic actions through complex regulation of pre- and post-synaptic acetylcholine receptors. Although striatal CINs have a well-defined electrophysiological profile, their biochemical properties are poorly understood, likely due to their low proportion within the striatum (2-3%). We report a strong and sustained phosphorylation of ribosomal protein S6 on its serine 240 and 244 residues (p-Ser(240-244)-S6rp), a protein integrant of the ribosomal machinery related to the mammalian target of the rapamycin complex 1 (mTORC1) pathway, which we found to be principally expressed in striatal CINs in basal conditions. We explored the functional relevance of this cellular event by pharmacologically inducing various sustained physiological activity states in CINs and assessing the effect on the levels of S6rp phosphorylation. Cell-attached electrophysiological recordings from CINs in a striatal slice preparation showed an inhibitory effect of tetrodotoxin (TTX) on action potential firing paralleled by a decrease in the p-Ser(240-244)-S6rp signal as detected by immunofluorescence after prolonged incubation. On the other hand, elevation in extracellular potassium concentration and the addition of apamin generated an increased firing rate and a burst-firing activity in CINs, respectively, and both stimulatory conditions significantly increased Ser(240-244)-S6rp phosphorylation above basal levels when incubated for one hour. Apamin generated a particularly large increase in phosphorylation that was sensitive to rapamycin. Taken together, our results demonstrate for the first time a link between the state of neuronal activity and a biochemical signaling event in striatal CINs, and suggest that immunofluorescence can be used to estimate the cellular activity of CINs under different pharmacological and/or behavioral conditions.