Effect of spike blockade on the receptive-field size of amacrine and ganglion cells in the rabbit retina
Effect of spike blockade on the receptive-field size of amacrine and ganglion cells in the rabbit retina
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DOI：
10.1152/jn.1996.75.5.1878
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发表时间：
1996-05-01
影响因子：
2.5
通讯作者：
Bloomfield, SA
中科院分区：
文献类型：
--
作者：
Bloomfield, SA
1.在离体灌流的兔视网膜眼杯中，从21个无长突细胞和12个神经节细胞获得细胞内记录。随后用辣根过氧化物酶（HRP）或N-（2-氨乙基）-生物素酰胺盐酸盐（Neurobiotinol）标记细胞进行形态学鉴定.对三个无长突细胞和三个神经节细胞进行的初步实验表明，1 μ M河豚毒素（TTX）取消所有的尖峰。这包括在许多无长突细胞中记录的大振幅和小振幅尖峰，表明它们是由电压门控钠通道介导的。18个无长突细胞和9个神经节细胞的中心感受野大小是用一个50 μ m宽/6.0 mm长的矩形光狭缝测量的，该光狭缝沿着其短轴（平行于视觉条纹）以小至3 μ m的步长位移。然后将视网膜浸泡在1 μ M TTX中，或者将单个细胞注射50 mM QX-314（一种季铵利多卡因衍生物）以消除所有尖峰，然后重新测量每个细胞的中心感受野。虽然TTX阻止尖峰在所有的神经节细胞（树突直径范围从302到969 μ m），它产生的中心感受野的大小没有显着的变化。这一发现表明，突触输入到神经节细胞树突的被动电紧张性传播足以有效地从终末分支传播到索马;通过电压门控钠通道的主动传播没有明显的作用。TTX和QX-314对无长突细胞感受野的影响不同，且与树突的大小有关。而TTX对无长突细胞的感受野大小没有显著影响，
1. Intracellular recordings were obtained from 21 amacrine cells and 12 ganglion cells in the isolated, superfused retina-eyecup of the rabbit. Cells were subsequently labeled with horseradish peroxidase (HRP) or N-(2-aminoethyl)-biotinamide hydrochloride (Neurobiotin) for morphologic identification.2. Initial experiments performed on three amacrine cells and three ganglion cells showed that 1 mu M tetrodotoxin (TTX) abolished all spiking. This included both large-amplitude and small-amplitude spikes recorded in many amacrine cells, indicating that they are mediated by voltage-gated sodium channels.3. The center-receptive-field size of 18 amacrine cells and 9 ganglion cells was measured with the use of a 50-mu m-wide/6.0-mm-long rectangular slit of light that was displaced along its minor axis (parallel to the visual streak) in steps as small as 3 mu m. The retina was then bathed in 1 mu M TTX, or individual cells were injected with 50 mM QX-314, a quaternary lidocaine derivative, to abolish all spiking, and the center-receptive field of each cell was then remeasured.4. Although TTX blocked spiking in all ganglion cells (dendritic diameters ranging from 302 to 969 mu m), it produced no significant change in the size of their center-receptive fields. This finding argues that passive, electrotonic spread of synaptic inputs to ganglion cell dendritic arbors is adequate for efficient propagation from terminal branches to the soma; active propagation via voltage-gated sodium channels plays no apparent role.5. In contrast, TTX and QX-314 had variable effect on the receptive fields of amacrine cells, which was related to the size of their dendritic arbors. Whereas TTX had no significant effect on the receptive-field size of amacrine cells whose dendritic arbors were