Evidence for the identification of synaptic transmitters released by photoreceptors of the toad retina.
Evidence for the identification of synaptic transmitters released by photoreceptors of the toad retina.
复制标题
识别蟾蜍视网膜光感受器释放的突触递质的证据。
DOI：
10.1113/jphysiol.1983.sp014497
复制
发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Schwartz,EA
中科院分区：
文献类型：
--
作者：
Miller,AM;Schwartz,EA
1.用藜芦碱、红藻氨酸和L-α-氨基己二酸孵育后，光感受器细胞存活，其他大部分神经元死亡。这种分离的光感受器细胞的制备从培养介质中积累了放射性分子，并将其代谢成标记的化合物。当一种制剂被放在过滤器上并进行超融合时，释放到灌流液中的放射性分子可以被收集起来，然后进行分析。使用了几种程序来诱导可能的递质化合物的释放。每一种释放的化合物都经过了化学鉴定。2.在缺钙含钴的培养液中，随着钾浓度的增加，天冬氨酸、谷氨酸和N-乙酰组氨酸三种化合物的释放量增加。3.除钴和钙回胞外培养时，这些化合物的释放量进一步增加。4.在钙存在的去极化过程中，还释放了腐胺和腐胺两种化合物。5.同质交换和异质交换也增加了第2节所列化合物的外流。至少对于天冬氨酸来说，交换是依赖于钠的。6.通过增加[~3H]GABA从分离的水平细胞外流的能力来测试释放的化合物的突触后效应。0。1 mM-L-天冬氨酸或L-谷氨酸可增加GABA的外流。N-乙酰组氨酸、腐胺和身体碱无效。7.分离的光感受器和完整的视网膜与[~3H]天冬氨酸或[~3H]腐胺孵育。随后的组织学和放射自显影表明，这两种化合物都选择性地被锥体蓄积。
1. When toad retinae were incubated with veratrine, kainic acid, and L‐alpha‐aminoadipic acid, photoreceptor cells survived and most other neurones died. This preparation of ‘isolated’ photoreceptor cells accumulated radioactive molecules from the incubation medium and metabolized these into labelled compounds. When a preparation was placed on a filter and superfused, radioactive molecules which were released into the superfusion fluid could be collected and later analysed. Several procedures were used for inducing the release of possible transmitter compounds. Each released compound was chemically identified. 2. Three compounds, aspartic acid, glutamic acid, and N‐acetyl histidine, were released when the potassium concentration was increased in media that lacked calcium and contained cobalt. 3. The release of these compounds was further increased when cobalt was removed and calcium returned to the extracellular medium. 4. Two additional compounds, putrescine and cadavarine, were also released during depolarization when calcium was present. 5. The efflux of each of the compounds listed in Section 2 was also increased by homo‐ and hetero‐exchange. For at least aspartate, exchange was sodium‐dependent. 6. The post‐synaptic effect of released compounds was tested by their ability to increase the efflux of [3H]GABA from ‘isolated’ horizontal cells. 0 . 1 mM‐L‐aspartate, or L‐glutamate produced an increase in GABA efflux. N‐acetyl histidine, putrescine, and cadavarine were ineffective. 7. Isolated photoreceptors and intact retinae were incubated with [3H]aspartate, or [3H]putrescine. Subsequent histology and autoradiography demonstrated that both compounds were selectively accumulated by cones.