Glickman R D, Adolph A R, Dowling J E
Brain Res. 1982 Feb 18;234(1):81-99. doi: 10.1016/0006-8993(82)90474-7.
Th effects on ganglion cell light responses and spontaneous activity of neurotransmitter candidates, applied by nebulizer spray and iontophoresis, were studied in the isolated carp retina. ACh, GABA, and substance P had strong effects on the ganglion cells; dopamine and the amino acids aspartate, glutamate, and glycine and only weak effects. ACh and substance P exerted their actions even when synaptic transmission was blocked by cobalt chloride, suggesting postsynaptic receptors for those agents on the ganglion cell membrane. The 3 amino acids and dopamine do not appear to act directly on the ganglion cells. The pharmacological sensitivity of ganglion cells was correlated with their physiological response type. About three-quarters of ON/OFF and half of other transiently responding ganglion cells were excited by micromolar concentrations of cholinergic agonists; most ON-center sustained ganglion cells were insensitive. The light response of some of the ACh-sensitive cells could be suppressed by cholinergic antagonists. Substance P generally excited ganglion cells with an ON-component in their light response. GABA inhibited cells of all response types, but affected least the OFF-center tonic cells. In view of these observations, and of corroborating histological evidence, we propose that ACh, GABA, and substance P are neurotransmitters that are released by amacrine cells and affect receptors located on ganglion cells.
在离体鲤鱼视网膜中，研究了通过雾化喷雾和离子导入施加的神经递质候选物对神经节细胞光反应和自发活动的影响。乙酰胆碱（ACh）、γ-氨基丁酸（GABA）和P物质对神经节细胞有强烈影响；多巴胺以及氨基酸天冬氨酸、谷氨酸和甘氨酸只有微弱影响。即使突触传递被氯化钴阻断，乙酰胆碱和P物质仍能发挥作用，这表明神经节细胞膜上存在这些物质的突触后受体。这三种氨基酸和多巴胺似乎不会直接作用于神经节细胞。神经节细胞的药理敏感性与其生理反应类型相关。大约四分之三的开/关型和一半的其他瞬态反应神经节细胞在微摩尔浓度的胆碱能激动剂作用下被兴奋；大多数开中心持续型神经节细胞不敏感。一些对乙酰胆碱敏感的细胞的光反应可被胆碱能拮抗剂抑制。P物质通常会兴奋那些光反应中有开成分的神经节细胞。GABA抑制所有反应类型的细胞，但对离中心紧张型细胞影响最小。鉴于这些观察结果以及确凿的组织学证据，我们提出乙酰胆碱、GABA和P物质是由无长突细胞释放并作用于神经节细胞上受体的神经递质。
