Ding S L, Elberger A J
Department of Anatomy and Neurobiology, University of Tennesse at Memphis 38163, USA.
J Neurosci Methods. 1995 Mar;57(1):67-75. doi: 10.1016/0165-0270(94)00127-3.
Biotinylated dextran amine (BDA) has proven to be an excellent anterograde tracer in adult mammalian brains, having some advantages over other anterograde tracers such as Phaseolus vulgaris-leucoagglutinin (PHA-L) and biocytin. However, results are inferior when BDA is used in neonatal mammals. To improve the sensitivity and quality of BDA labeling in neonatal mammalian brains, the tetramethylbenzidine-sodium tungstate (TMB-ST) method for horseradish peroxidase (HRP) histochemistry was modified and used in BDA histochemistry. After BDA application to the visual cortex of neonatal rat and cat, contralateral and ipsilateral cortical and subcortical regions were examined for BDA-labeled exons and terminals. The modified BDA histochemistry produced corpus callosum (CC) axons in neonatal rat and cat that were heavily and continuously labeled. The distribution, trajectories, branching and termination of individual CC axons, and even possible axon-axon contracts, were clearly identified in exquisite detail, even at low magnification. The quality of BDA labeling in the ipsilateral lateral geniculate nucleus and superior colliculus was similar to that of the CC axonal labeling. These results indicate that the modified BDA histochemistry provides a very sensitive and reliable approach to revealing the detailed distribution and morphology of projecting axons and terminals in the developing mammalian nervous system.
生物素化葡聚糖胺（BDA）已被证明是成年哺乳动物大脑中一种出色的顺行示踪剂，相对于其他顺行示踪剂，如菜豆白细胞凝集素（PHA-L）和生物胞素，具有一些优势。然而，在新生哺乳动物中使用BDA时，结果较差。为了提高新生哺乳动物大脑中BDA标记的敏感性和质量，对辣根过氧化物酶（HRP）组织化学的四甲基联苯胺-钨酸钠（TMB-ST）方法进行了改进，并用于BDA组织化学。将BDA应用于新生大鼠和猫的视觉皮层后，检查对侧和同侧皮质及皮质下区域中BDA标记的外显子和终末。改进后的BDA组织化学在新生大鼠和猫中产生了大量且连续标记的胼胝体（CC）轴突。即使在低倍放大下，也能极其详细地清晰识别单个CC轴突的分布、轨迹、分支和终末，甚至可能的轴突-轴突连接。同侧外侧膝状体和上丘中BDA标记的质量与CC轴突标记的质量相似。这些结果表明，改进后的BDA组织化学为揭示发育中的哺乳动物神经系统中投射轴突和终末的详细分布和形态提供了一种非常敏感和可靠的方法。
