Identification of cyclic ADP-ribose-dependent mechanisms in pancreatic muscarinic Ca2+ signaling using CD38 knockout mice
Identification of cyclic ADP-ribose-dependent mechanisms in pancreatic muscarinic Ca2+ signaling using CD38 knockout mice
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DOI：
10.1074/jbc.m004469200
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发表时间：
2001-01-05
影响因子：
4.8
通讯作者：
Maruyama, Y
中科院分区：
文献类型：
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作者：
Fukushi, Y;Kato, I;Maruyama, Y
我们发现，毒蕈碱乙酰胆碱（ACh）刺激增加了正常小鼠胰腺腺泡细胞中cADPR的细胞含量，但在CD 38基因敲除小鼠中没有。通过使用Fura-2显微荧光法监测ACh诱发的胞质Ca 2+浓度（[Ca 2 +]（i））的增加，我们区分并表征了响应于cADPR的Ca 2+释放机制。来自敲除小鼠（KO细胞）的细胞的Ca 2+响应缺乏野生小鼠中存在的毒蕈碱Ca 2+释放的两个组分。低浓度ACh诱导的第一组分有助于再生Ca ~（2+）峰。这一成分在正常细胞中被ryanodine消除，在KO细胞中被严重破坏，表明低ACh诱导的再生峰电位反应是由一类ryanodine受体调节的cADPR依赖性Ca ~（2+）释放池引起的。高浓度ACh诱导的第二成分参与时相性Ca ~（2+）反应，ryanodine处理不消除它。总体而言，我们得出结论，毒蕈碱Ca 2+信号在胰腺腺泡细胞中涉及一个CD 38依赖性途径负责两个cADPR依赖性Ca 2+释放机制，其中一个敏感的ryanodine起着至关重要的作用，产生重复的Ca 2+尖峰。
We showed that muscarinic acetylcholine (ACh)-stimulation increased the cellular content of cADPR in the pancreatic acinar cells from normal mice but not in those from CD38 knockout mice. By monitoring ACh-evoked increases in the cytosolic Ca2+ concentration ([Ca2+](i)) using fura-2 microfluorimetry, we distinguished and characterized the Ca2+ release mechanisms responsive to cADPR, The Ca2+ response from the cells of the knockout mice (KO cells) lacked two components of the muscarinic Ca2+ release present in wild mice. The first component inducible by the low concentration of ACh contributed to regenerative Ca2+ spikes. This component was abolished by ryanodine treatment in the normal cells and was severely impaired in KO cells, indicating that the low ACh-induced regenerative spike responses were caused by cADPR-dependent Ca2+ release from a pool regulated by a class of ryanodine receptors, The second component inducible by the high concentration of ACh was involved in the phasic Ca2+ response, and it was not abolished by ryanodine treatment. Overall, we conclude that muscarinic Ca2+ signaling in pancreatic acinar cells involves a CD38-dependent pathway responsible for two cADPR-dependent Ca2+ release mechanisms in which the one sensitive to ryanodine plays a crucial role for the generation of repetitive Ca2+ spikes.