Glutamate receptor activation triggers a calcium-dependent and SNARE protein-dependent release of the gliotransmitter D-serine
Glutamate receptor activation triggers a calcium-dependent and SNARE protein-dependent release of the gliotransmitter D-serine
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DOI：
10.1073/pnas.0408483102
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发表时间：
2005-04-12
影响因子：
11.1
通讯作者：
Baux, G
中科院分区：
文献类型：
--
作者：
Mothet, JP;Pollegioni, L;Baux, G
胶质递质d -丝氨酸在(S)- α -氨基-3-羟5-甲基-4-异恶唑丙酸/海因酸盐和代谢性谷氨酸受体刺激下释放，但其机制尚不清楚。在这里，通过使用高灵敏度的生物测定法连续监测细胞外d -丝氨酸水平，我们研究了其释放的途径。我们发现d -丝氨酸的释放可以通过去除细胞外钙来抑制，通过增加细胞外钙或用Ca2+离子载体A23187处理后来增强。此外，在消耗了对thapsigargin敏感的细胞内Ca2+储存或与1,2-二（2-氨基苯氧基）乙烷-N，N，N‘，N’-四乙酸酯-乙酰氧基甲酯螯合细胞内Ca2+后，氨基酸的释放大大减少。有趣的是，康那霉素A（一种液泡型H+- atp酶抑制剂）也显著减少了d -丝氨酸的释放，这表明囊泡质子梯度在递质储存/释放中的作用。此外，激动剂诱发的d -丝氨酸释放对破伤风神经毒素敏感。最后，免疫细胞化学和蔗糖密度梯度分析显示，很大一部分d -丝氨酸与synaptobrevin/VAMP2共定位，表明它储存在携带VAMP2的囊泡中。总之，我们的研究揭示了d -丝氨酸释放的细胞机制，并强调了胶质细胞胞外通路在影响中枢神经系统细胞外d -丝氨酸水平方面的重要性。
The gliotransmitter D-serine is released upon (S)-alpha-amino-3-hydroxy5-methyl-4-isoxazolepropionic acid/kainate and metabotropic glutamate receptor stimulation, but the mechanisms involved are unknown. Here, by using a highly sensitive bioassay to continuously monitor extracellular D-serine levels, we have investigated the pathways used in its release. We reveal that D-serine release is inhibited by removal of extracellular calcium and augmented by increasing extracellular calcium or after treatment with the Ca2+ ionophore A23187. Furthermore, release of the amino acid is considerably reduced after depletion of thapsigargin-sensitive intracellular Ca2+ stores or chelation of intracellular Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate-acetoxy-methyl ester. Interestingly, D-serine release also was markedly reduced by concanamycin A, a vacuolar-type H+-ATPase inhibitor, indicating a role for the vesicular proton gradient in the transmitter storage/release. In addition, agonist-evoked D-serine release was sensitive to tetanus neurotoxin. Finally, immunocytochemical and sucrose density gradient analysis revealed that a large fraction of D-serine colocalized with synaptobrevin/VAMP2, suggesting that it is stored in VAMP2-bearing vesicles. In summary, our study reveals the cellular mechanisms subserving D-serine release and highlights the importance of the glial cell exocytotic pathway in influencing CNS levels of extracellular D-serine.