Activation of metabotropic glutamate receptors modulates the voltage-gated sustained calcium current in a teleost horizontal cell.
Activation of metabotropic glutamate receptors modulates the voltage-gated sustained calcium current in a teleost horizontal cell.
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代谢型谷氨酸受体的激活调节硬骨鱼水平细胞中电压门控的持续钙电流。
DOI：
10.1152/jn.1999.81.2.425
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Gafka,AC
中科院分区：
文献类型：
--
作者：
Linn,CL;Gafka,AC
代谢型谷氨酸受体的激活调节硬骨鱼水平细胞的电压门控持续钙电流。 在硬骨鱼视网膜中，视锥水平细胞含有电压激活的持续钙电流，已被认为参与视觉处理。最近，几项研究表明，电压门控通道的调制可以通过代谢型谷氨酸受体（mGluRs）的激活而发生。由于谷氨酸是脊椎动物视网膜中的兴奋性神经递质，我们已经使用全细胞电生理技术来研究mGluR激活对鲶鱼视网膜中孤立的视锥水平细胞中发现的持续电压门控钙电流的影响。在阻断电压门控钠和钾通道以及N-甲基-d-天冬氨酸（NMDA）和非NMDA通道的药理学条件下，应用1-谷氨酸或1-氨基环戊烷-1，3-二羧酸（1S，3R-ACPD）对电压钳制的视锥水平细胞有增加钙电流幅度的作用，将钙电流的激活范围扩大10 mV，进入细胞的生理工作范围，并将峰值钙电流偏移− 5 mV。为了鉴定和表征在鲶鱼视锥水平细胞上发现的mGluR亚型，通过灌注施加I组、II组或III组mGluR的激动剂。第I组和第III组mGluR激动剂模拟L-谷氨酸或1S，3R-ACPD的作用，而第II组mGluR激动剂对L-型钙电流活性没有影响。抑制研究表明I组mGluR拮抗剂显著阻断I组mGluR激动剂（S）-3，5-二羟基苯甘氨酸的调节作用。当在存在III组mGluR拮抗剂的情况下应用III组mGluR激动剂1 - 2-氨基-4-膦酰基丁酸时，获得了类似的结果。这些结果为鲶鱼视锥水平细胞上的两组mGluR亚型提供了证据。这些mGluRs的激活与电压门控持续钙电流的调节有关。
Activation of metabotropic glutamate receptors modulates the voltage-gated sustained calcium current in a teleost horizontal cell. In the teleost retina, cone horizontal cells contain a voltage-activated sustained calcium current, which has been proposed to be involved in visual processing. Recently, several studies have demonstrated that modulation of voltage-gated channels can occur through activation of metabotropic glutamate receptors (mGluRs). Because glutamate is the excitatory neurotransmitter in the vertebrate retina, we have used whole cell electrophysiological techniques to examine the effect of mGluR activation on the sustained voltage-gated calcium current found in isolated cone horizontal cells in the catfish retina. In pharmacological conditions that blocked voltage-gated sodium and potassium channels, as well asN-methyl-d-aspartate (NMDA) and non-NMDA channels, application ofl-glutamate or 1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) to voltage-clamped cone horizontal cells acted to increase the amplitude of the calcium current, expand the activation range of the calcium current by 10 mV into the cell’s physiological operating range, and shift the peak calcium current by −5 mV. To identify and characterize the mGluR subtypes found on catfish cone horizontal cells, agonists of group I, group II, or group III mGluRs were applied via perfusion. Group I and group III mGluR agonists mimicked the effect ofl-glutamate or 1S,3R-ACPD, whereas group II mGluR agonists had no effect on L-type calcium current activity. Inhibition studies demonstrated that group I mGluR antagonists significantly blocked the modulatory effect of the group I mGluR agonist, (S)-3,5-dihydroxyphenylglycine. Similar results were obtained when the group III mGluR agonist,l-2-amino-4-phosphonobutyric acid, was applied in the presence of a group III mGluR antagonist. These results provide evidence for two groups of mGluR subtypes on catfish cone horizontal cells. Activation of these mGluRs is linked to modulation of the voltage-gated sustained calcium current.