Responses of rod bipolar cells isolated from dogfish retinal slices to concentration-jumps of glutamate
Responses of rod bipolar cells isolated from dogfish retinal slices to concentration-jumps of glutamate
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从角鲨视网膜切片中分离出的杆状双极细胞对谷氨酸浓度跳跃的反应
DOI：
10.1017/s0952523800006970
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发表时间：
1994
影响因子：
1.9
通讯作者：
G. Falk
中科院分区：
文献类型：
--
作者：
R. Shiells;G. Falk
杆状双极细胞的光响应是由一类代谢性谷氨酸受体介导的，该受体通过g蛋白偶联控制cGMP级联，cGMP作用于打开阳离子通道，而非双极细胞具有离子性谷氨酸受体。从适应黑暗的角鲨视网膜切片的双极细胞和双极细胞中获得全细胞电压钳记录，通过它们的光反应来识别。离体细胞暴露于谷氨酸浓度跳跃。在负电压箝位电位下，双极上细胞对谷氨酸的反应是向外电流，平均延迟10.8 ms，而非双极上细胞对内向电流的反应没有任何延迟。两种细胞类型均未表现出对谷氨酸应用步骤的脱敏。双极细胞的剂量-响应关系没有逐渐饱和，但在谷氨酸浓度超过200 μM时呈线性增加。假设谷氨酸作用于受体的Michaelis-Menten动力学和与谷氨酸结合的受体浓度与cGMP下降之间存在线性关系，这种剂量-反应关系可以用理论表达来拟合。在低谷氨酸浓度下，非双极细胞的剂量-反应关系呈饱和状态，极限斜率为2，表明需要两个谷氨酸分子通过合作机制打开每个通道。杆状双极细胞的谷氨酸受体偶联cGMP级联可以解释高突触电压增益。
Abstract Rod on-bipolar cell light responses are mediated by a class of metabotropic glutamate receptor which is coupled via a G-protein to the control of a cGMP cascade, with cGMP acting to open cation channels, whilst off-bipolar cells possess ionotropic glutamate receptors. Whole-cell voltage-clamp recordings were obtained from on- and off-bipolar cells of dark-adapted dogfish retinal slices, identified by their light responses. Isolated cells were exposed to concentration-jumps of glutamate. At negative voltage-clamp potentials, on-bipolar cells responded to glutamate with outward currents with a mean delay of 10.8 ms, whilst off-bipolar cells responded with inward currents without any delay. Neither cell type showed desensitization to applied steps of glutamate. The dose-response relation for on-bipolar cells showed no gradual saturation, but increased linearly with a sharp cutoff above 200 μM glutamate. This dose-response relation could be fitted with a theoretical expression assuming Michaelis-Menten kinetics for the action of glutamate on receptors and a linear relation between the concentration of receptors bound to glutamate and the fall in cGMP this induces. The dose-response relation of off-bipolar cells showed saturation with a limiting slope of 2 at low glutamate concentrations, suggesting that two molecules of glutamate are required to open each channel by a cooperative mechanism. The glutamate receptor coupled cGMP cascade of rod on-bipolar cells can account for high synaptic voltage gain.
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蝾螈视网膜杆对外部钙浓度变化的反应的外部和内部作用。
DOI：
10.1113/jphysiol.1988.sp017259
发表时间：
1988
期刊：
The Journal of physiology
影响因子：
--
作者：
Lamb,TD;Matthews,HR
通讯作者：
Matthews,HR
从光感受器到泥小狗视网膜双极细胞的突触传递特性。
影响因子：
2.5
作者：
Kim,HG;Miller,RF
通讯作者：
Miller,RF
DOI：
10.1016/s0021-9258(18)69267-1
发表时间：
1986-10
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
A. Ames;T. Walseth;R. Heyman;M. Barad;R. Graeff;N. D. Goldberg
通讯作者：
A. Ames;T. Walseth;R. Heyman;M. Barad;R. Graeff;N. D. Goldberg
影响因子：
56.9
作者：
GILBERTSON, TA;SCOBEY, R;WILSON, M
通讯作者：
WILSON, M
影响因子：
5.5
作者：
COBBS, WH;PUGH, EN
通讯作者：
PUGH, EN