Pycock C J
Surv Ophthalmol. 1985 Mar-Apr;29(5):355-65. doi: 10.1016/0039-6257(85)90111-0.
The mammalian retina is classically divided into ten layers which contain the neuronal elements identified as photoreceptors, horizontal cells, bipolar cells, amacrine cells and ganglion cells. Using various neuroscientific techniques possible neurotransmitter substances have been assigned to each of these cell types. Thus the localization of transmitter synthesizing enzymes and storage vesicles, the demonstration of release of transmitter in response to specific stimuli, the observation of post-synaptic events mimicked or blocked by the iontophoretic application of exogenous transmitter/agonist or antagonist drug respectively, and the identification of efficient transmitter inactivation mechanisms synaptically add evidence for the association of certain proposed transmitter substances with specific neuronal elements. The evidence for the proposal that the excitatory amino acids glutamate and aspartate are transmitters of photoreceptors, that gamma-aminobutyric acid (GABA) is the inhibitory transmitter of horizontal and amacrine cells, that acetylcholine is associated with the functioning of bipolar cells, and that taurine, glycine and dopamine may all also play neurotransmitter or neuromodulatory roles at amacrine cell synapses is discussed.
传统上，哺乳动物的视网膜被分为十层，其中包含被确定为光感受器、水平细胞、双极细胞、无长突细胞和神经节细胞的神经元成分。运用各种神经科学技术，已将可能的神经递质物质分配给这些细胞类型中的每一种。因此，递质合成酶和储存囊泡的定位、递质在特定刺激下释放的证明、分别通过离子导入外源性递质/激动剂或拮抗剂药物模拟或阻断的突触后事件的观察，以及有效的递质失活机制的鉴定，都从突触角度为某些提出的递质物质与特定神经元成分的关联提供了证据。文中讨论了以下提议的证据：兴奋性氨基酸谷氨酸和天冬氨酸是光感受器的递质，γ-氨基丁酸（GABA）是水平细胞和无长突细胞的抑制性递质，乙酰胆碱与双极细胞的功能相关，以及牛磺酸、甘氨酸和多巴胺可能在无长突细胞突触中都发挥神经递质或神经调节作用。
