Zhang L, McClellan A D
Division of Biological Sciences, University of Missouri, Columbia 65211-6190, USA.
J Neurosci Methods. 1998 Nov 1;85(1):51-62. doi: 10.1016/s0165-0270(98)00116-2.
In larval lamprey, seven fluorescent tracers were tested as potential candidates for retrograde double labeling of descending brain neurons: Fluoro Gold (FG); fluorescein dextran amine (FDA); True Blue (TB); cascade blue dextran amine (CBDA); Fast Blue (FB); Texas red dextran amine (TRDA); and tetramethylrhodamine dextran amine (RDA). The first tracer (FG, TB, FB, or CBDA) was applied to the spinal cord at 40% body length (BL). In separate experiments, the second tracer (TRDA or RDA) was applied to the spinal cord at 20% BL. The tracer combination FG/TRDA was found to have the best optical properties for double labeling. However, application of FG to the spinal cord with the method used for the other tracers resulted in labeling of 'lateral cells' along the sides of the rhombencephalon that were presumed to be non-neuronal and that obscured some of the descending brain neurons. Control experiments suggested that FG was transported in the circulation to the brain, where the tracer was taken up by lateral cells. Therefore, a special technique was developed for applying FG to the spinal cord without allowing the tracer to enter the circulation. In larval lamprey, this important double-labeling technique that was developed for TRDA and FG is being used to examine axonal regeneration and projection patterns of descending brain neurons.
在七鳃鳗幼体中，测试了七种荧光示踪剂作为下行脑神经元逆行双重标记的潜在候选物：氟金（FG）；荧光素葡聚糖胺（FDA）；真蓝（TB）；级联蓝葡聚糖胺（CBDA）；快蓝（FB）；德克萨斯红葡聚糖胺（TRDA）；以及四甲基罗丹明葡聚糖胺（RDA）。第一种示踪剂（FG、TB、FB或CBDA）在体长40%处施加于脊髓。在单独的实验中，第二种示踪剂（TRDA或RDA）在体长20%处施加于脊髓。发现示踪剂组合FG/TRDA具有最佳的双重标记光学特性。然而，用与其他示踪剂相同的方法将FG施加于脊髓，导致在菱脑两侧标记出“外侧细胞”，这些细胞被认为是非神经元细胞，并且遮挡了一些下行脑神经元。对照实验表明，FG通过循环系统运输到大脑，在那里示踪剂被外侧细胞摄取。因此，开发了一种特殊技术来将FG施加于脊髓，同时不让示踪剂进入循环系统。在七鳃鳗幼体中，这种为TRDA和FG开发的重要双重标记技术正被用于研究下行脑神经元的轴突再生和投射模式。
