In vitro activation of murine DRG neurons by CGRP-mediated mucosal mast cell degranulation
In vitro activation of murine DRG neurons by CGRP-mediated mucosal mast cell degranulation
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DOI：
10.1152/ajpgi.00528.2003
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发表时间：
2004-07-01
影响因子：
4.5
通讯作者：
Kroese, ABA
中科院分区：
文献类型：
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作者：
De Jonge, F;De Laet, A;Kroese, ABA
伴随肥大细胞增多的CGRP免疫反应（IR）初级传入神经纤维的上调是曼氏血吸虫感染小鼠回肠的特征。这些粘膜肥大细胞（MMC）和CGRP-IR纤维，起源于背根（DRG）和结状神经节，被发现在密切的并列。我们通过共聚焦记录细胞内Ca ~（2+）浓度（[Ca ~（2+）]（i））来研究体外原代培养的MMC和CGRP-IR DRG神经元之间的相互作用。通过测量颗粒糜酶（小鼠肥大细胞蛋白酶-1）的细胞外释放来确定肥大细胞促分泌素化合物48/80（C48/80; 10 μ g/ml）和神经肽CGRP（2.10（-8）M）和P物质（SP; 3.10（-8）M）的脱颗粒EC 50。将C48/80（10 μ g/ml）、CGRP和SP（均为10（-7）M）应用于加载Fluo-4的MMC，在滞后时间后诱导[Ca 2 +]（i）短暂升高，表明肥大细胞脱粒和/或分泌。CGRP反应可被百日咳毒素（2 μ g/ml）完全阻断，表明G（i）蛋白参与。将通过MMC C48/80脱颗粒获得的MMC汁应用于负载Fluo-4的背根神经节神经元，诱导所有神经元中[Ca 2 +]（i）升高，表明激活。在含有Fluo-4负载的DRG神经元的培养皿中，C48/80对MMC的脱粒也引起DRG神经元的激活。总之，这些结果证明了体外培养的MMC和CGRP-IR DRG神经元之间的双向串扰。这表明，这种通讯可能是MMC和CGRP-IR神经纤维在体内紧密贴壁的功能相关性。
Upregulation of CGRP-immunoreactive (IR) primary afferent nerve fibers accompanied by mastocytosis is characteristic for the Schistosoma mansoni-infected murine ileum. These mucosal mast cells (MMC) and CGRP-IR fibers, which originate from dorsal root (DRG) and nodose ganglia, are found in close apposition. We examined interactions between primary cultured MMC and CGRP-IR DRG neurons in vitro by confocal recording of intracellular Ca2+ concentration ([Ca2+](i)). The degranulatory EC50 for the mast cell secretagogue compound 48/80 (C48/80; 10 mug/ml) and the neuropeptides CGRP (2.10(-8) M) and substance P (SP; 3.10(-8) M) were determined by measurement of extracellular release of the granule chymase, mouse mast cell protease-1. Application of C48/80 (10 mug/ml) and CGRP and SP (both 10(-7) M) to Fluo-4-loaded MMC induced a transient rise in [Ca2+](i) after a lag time, indicative of mast cell degranulation and/or secretion. The CGRP response could be completely blocked by pertussis toxin (2 mug/ml), indicating involvement of G(i) proteins. Application of MMC juice, obtained by C48/80 degranulation of MMC, to Fluo-4-loaded DRG neurons induced in all neurons a rise in [Ca2+](i), indicative of activation. Degranulation of MMC by C48/80 in culture dishes containing Fluo-4-loaded DRG neurons also caused activation of the DRG neurons. In conclusion, these results demonstrate a bidirectional cross-talk between cultured MMC and CGRP-IR DRG neurons in vitro. This indicates that such a communication may be the functional relevance for the close apposition between MMC and CGRP-IR nerve fibers in vivo.