Amplification of depolarization‐induced and ryanodine‐sensitive cytosolic Ca2+ elevation by synthetic carbocyclic analogs of cyclic ADP‐ribose and their antagonistic effects in NG108‐15 neuronal cells
Amplification of depolarization‐induced and ryanodine‐sensitive cytosolic Ca2+ elevation by synthetic carbocyclic analogs of cyclic ADP‐ribose and their antagonistic effects in NG108‐15 neuronal cells
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DOI：
10.1111/j.1471-4159.2005.03197.x
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发表时间：
2005-07
影响因子：
4.7
通讯作者：
M. Hashii;S. Shuto;M. Fukuoka;T. Kudoh;A. Matsuda;H. Higashida
中科院分区：
文献类型：
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作者：
M. Hashii;S. Shuto;M. Fukuoka;T. Kudoh;A. Matsuda;H. Higashida
我们合成了在环状ADP-核糖（cADPR）的核糖单元（连接到腺嘌呤的N1的核糖）中修饰的类似物，cADPR是一种Ca 2+动员第二信使。在NG 108 - 15神经母细胞瘤×神经胶质瘤杂交细胞中测定这些类似物的生物活性，所述细胞预先加载有呋喃-2乙酰氧基甲酯并进行全细胞膜片钳。通过贴片移液器应用抗水解环状ADP-碳环-核糖（cADPcR）可增强去极化膜电位下细胞质游离Ca 2+浓度（[Ca 2 +]i）的升高。cADPcR输注细胞中持续膜去极化引起的[Ca 2 +]i增加显著大于非输注细胞，其程度相当于或显著大于cADPR或β-NAD+诱导的程度。8-氯-cADPcR和两种肌苷同系物（环IDP-碳环-核糖和8-溴-环IDP-碳环-核糖）未诱导与cADPcR或cADPR相似的效应。相反，与cADPR或cADPcR单独给药相比，8-chloro-cADPcR与cADPR或cADPcR联合给药可抑制去极化诱导的[Ca 2 +]i升高。这些结果表明，我们的cADPR类似物对去极化诱导的[Ca 2 +]i增加具有激动或拮抗作用，并表明哺乳动物神经元细胞中兰尼碱受体和电压激活的Ca 2+通道之间存在功能性相互偶联，通过cADPR。
We synthesized analogs modified in the ribose unit (ribose linked to N1 of adenine) of cyclic ADP‐ribose (cADPR), a Ca2+‐mobilizing second messenger. The biological activities of these analogs were determined in NG108‐15 neuroblastoma × glioma hybrid cells that were pre‐loaded with fura‐2 acetoxymethylester and subjected to whole‐cell patch‐clamp. Application of the hydrolysis‐resistant cyclic ADP‐carbocyclic‐ribose (cADPcR) through patch pipettes potentiated elevation of the cytoplasmic free Ca2+ concentration ([Ca2+]i) at the depolarized membrane potential. The increase in [Ca2+]i evoked upon sustained membrane depolarization was significantly larger in cADPcR‐infused cells than in non‐infused cells and its degree was equivalent to or significantly greater than that induced by cADPR or β‐NAD+. 8‐chloro‐cADPcR and two inosine congeners (cyclic IDP‐carbocyclic‐ribose and 8‐bromo‐cyclic IDP‐carbocyclic‐ribose) did not induce effects similar to those of cADPcR or cADPR. Instead, 8‐chloro‐cADPcR together with cADPR or cADPcR caused inhibition of the depolarization‐induced [Ca2+]i increase as compared with either cADPR or cADPcR alone. These results demonstrated that our cADPR analogs have agonistic or antagonistic effects on the depolarization‐induced [Ca2+]i increase and suggested the presence of functional reciprocal coupling between ryanodine receptors and voltage‐activated Ca2+ channels via cADPR in mammalian neuronal cells.