Casey Eye Institute, Department of Ophthalmology, Oregon Health and Sciences University, Portland, Oregon 97239, USA.
J Comp Neurol. 2011 Dec 15;519(18):3640-56. doi: 10.1002/cne.22756.
Detailed analysis of the synaptic inputs to the primate DB1 bipolar cell has been precluded by the absence of a suitable immunohistochemical marker. Here we demonstrate that antibodies for the EF-hand calcium-binding protein, secretagogin, strongly label the DB1 bipolar cell as well as a mixed population of GABAergic amacrine cells in the macaque retina. Using secretagogin as a marker, we show that the DB1 bipolar makes synaptic contact with both L/M as well as S-cone photoreceptors and only minimal contact with rod photoreceptors. Electron microscopy showed that the DB1 bipolar makes flat contacts at both triad-associated and nontriad-associated positions on the cone pedicle. Double labeling with various glutamate receptor subunit antibodies failed to conclusively determine the subunit composition of the glutamate receptors on DB1 bipolar cells. In the IPL, DB1 bipolar cell axon terminals expressed the glycine receptor, GlyRα1, at sites of contact with AII amacrine cells, suggesting that these cells receive input from the rod pathway.
详细分析灵长类 DB1 双极细胞的突触输入受到缺乏合适的免疫组织化学标志物的限制。在这里，我们证明了针对 EF 手钙结合蛋白分泌素的抗体强烈标记 DB1 双极细胞以及猕猴视网膜中的混合 GABA 能无长突细胞群体。使用分泌素作为标记物，我们表明 DB1 双极细胞与 L/M 和 S- cone 光感受器形成突触接触，而与 rod 光感受器的接触很少。电子显微镜显示 DB1 双极细胞在锥体足的三联体相关和非三联体相关位置形成扁平接触。用各种谷氨酸受体亚基抗体进行双重标记未能确定 DB1 双极细胞上谷氨酸受体的亚基组成。在 IPL 中，DB1 双极细胞轴突末端在与 AII 无长突细胞接触的部位表达甘氨酸受体 GlyRα1，表明这些细胞接收来自 rod 途径的输入。
