The Effect of Spider Toxin PhTx3-4, 蠅-Conotoxins MVIIA and MVIIC on Glutamate Uptake and on Capsaicin-Induced Glutamate Release and [Ca2+]i in Spinal cord Synaptosomes
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- 作者：Jomara M. Gon莽aves (1)
Juliano Ferreira (2)
Marco Antonio M. Prado (3)
Marta N. Cordeiro (4)
Michael Richardson (4)
Ana Cristina do Nascimento Pinheiro (5)
Marco A. Romano Silva (1)
Celio Jos茅 de Castro Junior (1)
Alessandra H. Souza (1)
Marcus Vinicius Gomez (15) marcusvgomez@gmail.com - 关键词：Spider and conus toxins – ; Capsaicin – ; Glutamate release – ; Glutamate uptake intracellular calcium – ; Spinal cord synaptosomes
- 刊名：Cellular and Molecular Neurobiology
- 出版时间：March 2011
- 出版年：2011
- 期刊代码：5_02724340
- 类别：env
- 卷：31
- 期：2
- 页码：277-283
- 数据来源：sp
摘要
In spinal cord synaptosomes, the spider toxin PhTx3-4 inhibited capsaicin-stimulated release of glutamate in both calcium-dependent and -independent manners. In contrast, the conus toxins, ω-conotoxin MVIIA and ω-conotoxin MVIIC, only inhibited calcium-dependent glutamate release. PhTx3-4, but not ω-conotoxin MVIIA or ω-conotoxin MVIIC, is able to inhibit the uptake of glutamate by synaptosomes, and this inhibition in turn leads to a decrease in the Ca2+-independent release of glutamate. No other polypeptide toxin so far described has this effect. PhTx3-4 and ω-conotoxins MVIIC and MVIIA are blockers of voltage-dependent calcium channels, and they significantly inhibited the capsaicin-induced rise of intracellular calcium [Ca2+]i in spinal cord synaptosomes, which likely reflects calcium entry through voltage-gated calcium channels. The inhibition of the calcium-independent glutamate release by PhTx3-4 suggests a potential use of the toxin to block abnormal glutamate release in pathological conditions such as pain.