A17 - A BROAD-FIELD AMACRINE CELL IN THE ROD SYSTEM OF THE CAT RETINA
A17 - A BROAD-FIELD AMACRINE CELL IN THE ROD SYSTEM OF THE CAT RETINA
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DOI：
10.1152/jn.1985.54.3.592
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发表时间：
1985-01-01
影响因子：
2.5
通讯作者：
KOLB, H
中科院分区：
文献类型：
--
作者：
NELSON, R;KOLB, H
1.用辣根过氧化物酶（HRP）微电极穿透猫视网膜A17无长突细胞，记录其光反应。这些细胞以持续的方式向光的步骤发展。2.在视网膜整体中观察到，注射HRP的细胞具有非常细的树突（0.1 μ m直径）的轮辐状放射状张开，其弥漫地穿过内网层（IPL）的所有层，主要在层4和5中延伸。在直径为500至1,200 μ m的树枝状区域上承载有多达1,000个大的、规则间隔的珠粒。细胞体大小范围为9至13 μ m。3.电镜下见强脉冲光B亚板层内的树突珠与视杆双极轴突终末形成突触。树突珠在sublamina很少使突触，但在这一层的珠之间，输入至少有三个独特的无长突发生。虽然在光镜水平上是弥散的，但A17在结构上似乎是双层的，在亚板a中有无长突输入，在亚板B中有双极输入。A17很可能与AI相同。4. A17信号几乎完全由杆驱动。光谱敏感性峰值在507 nm处，与色素上皮细胞的光谱敏感性相同。光适应消除了信号中除了一小部分超极化成分以外的所有成分。整体强度响应范围与AII无长突细胞相似。5.当A17细胞的感受野与狭缝刺激映射，广泛的，单分量曲线测量近似覆盖的树突状领域。感受野由平均空间常数为259 ± 1的线性电模型很好地描述。97 μ m（SD）。另一方面，对不同宽度的居中狭缝刺激的反应产生的空间常数仅为38 ± 1。29时因此，A17无长突是猫视杆系统的宽场成分，但空间整合能力很小。感受野测量不支持孤立的树突状区域的概念。
1. A17 amacrine cells of the cat retina have been penetrated with horseradish peroxidase (HRP)-filled microelectrodes and their light responses recorded. These cells depolarize in sustained fashion to steps of light. 2. Viewed in retinal wholemounts, HRP-injected cells have a spokelike radiating splay of very fine dendrites (0.1 .mu.m diam) passing diffusely through all strata of the inner plexiform layer (IPL) to run primarily in strata 4 and 5. There are as many as 1,000 large, regularly spaced beads borne on the 500-to 1,200-.mu.m diameter dendritic field. Cell body sizes range from 9 to 13 .mu.m. 3. In the electron microscope, the dendritic beads in sublamina b of the IPL are seen to synapse reciprocally with rod bipolar axon terminals. Dendritic beads in sublamina a rarely make synapses, but between the beads in this layer, input from at least three distinctive amacrine profiles occurs. Though diffuse at the light microscopic level, A17 thus appears to be structurally bistratified, with amacrine input in sublamina a and bipolar input in sublamina b. It is likely that A17 can be identified with AI. 4. A17 signals are driven almost exclusively by rods. The spectral sensitivity peaks at 507 nm, identical with that of pigment epithelial cells. Light adaptation abolishes all but a small hyperpolarizing component of the signal. The overall intensity-response range is similar to that of AII amacrine cells. 5. When receptive fields of A17 cells are mapped with slit stimuli, a broad, single-component curve is measured approximately covering the dendritic field. The receptive field is well described by a linear electrical model with a mean space constant of 259 .+-. 97 .mu.m (SD). On the other hand, responses to centered slit stimuli of varying width yielded space constants of only 38 .+-. 29 .mu.m. A17 amacrines are thus broad-field components of the cat''s rod system but with very little capacity for spatial integration. Receptive-field measurements are not supportive of the notion of isolated dendritic regions.