Yazulla S, Studholme K M, Zucker C L
J Comp Neurol. 1985 Jan 8;231(2):232-8. doi: 10.1002/cne.902310210.
A class of amacrine cells in the goldfish retina displays substance P-like immunoreactivity (SPIR). We studied the synaptic organization of SPIR amacrine cells by electron microscopical immunocytochemistry. Amacrine cells showing SPIR have processes which ramify in a very narrow band in layer 3 of the inner plexiform layer. SPIR is restricted to large dense-cored vesicles (DCVs), which are distributed throughout the dendrites. Processes labeled with SPIR contain a mixture of DCVs and numerous small agranular vesicles. Of 88 synaptic contracts analyzed, SPIR processes occurred as the presynaptic element 57 times and as the postsynaptic element 31 times. SPIR processes made synapses upon amacrine and ganglion cell dendrites with equal frequency and received synaptic input from both amacrine and bipolar cells. The stratification of SPIR amacrine cells in proximal sublamina a suggests that their synaptic interactions are restricted to "off" and "on-off" neurons. However, this is in contrast to published electrophysiological data. Possible explanations for this discrepancy are discussed in detail.
金鱼视网膜中的一类无长突细胞显示出P物质样免疫反应性（SPIR）。我们通过电子显微镜免疫细胞化学研究了SPIR无长突细胞的突触组织。显示SPIR的无长突细胞具有在内网状层第3层的非常窄的带中分支的突起。SPIR局限于大的致密核心囊泡（DCV），其分布于整个树突中。用SPIR标记的突起包含DCV和许多小的无颗粒囊泡的混合物。在分析的88个突触接触中，SPIR突起作为突触前成分出现57次，作为突触后成分出现31次。SPIR突起以相同的频率与无长突细胞和神经节细胞的树突形成突触，并从无长突细胞和双极细胞接收突触输入。SPIR无长突细胞在近端亚层a中的分层表明它们的突触相互作用仅限于“关闭”和“开-关”神经元。然而，这与已发表的电生理数据相反。详细讨论了这种差异的可能解释。
