Schmued L C, Swanson L W, Sawchenko P E
J Histochem Cytochem. 1982 Feb;30(2):123-8. doi: 10.1177/30.2.6174560.
Methods for counterstaining neural tissue that contains fluorescent markers have been developed. Acridine orange is useful for localizing cells that are retrogradely labelled with the fluorescent tracers true blue, bisbenzimide, and nuclear yellow because at low concentrations it yields a green Nissl stain when excited with blue, but not with ultraviolet, light; since the tracers fluoresce only when exposed to ultraviolet light, they are not masked by the counterstain. In addition, counterstaining at pH 2 increases bisbenzimide fluorescence considerably. Ethidium bromide is useful for immunohistochemistry (IHC) because it yields a bright red Nissl counterstain when excited by green light, and is only faintly visible when the fluorescein marker is excited with blue light, or when ultraviolet excitation is used. Ethidium bromide is therefore a good counterstain for fluorescent retrograde tracer and for combined IHC-retrograde tracer studies as well. Certain dyes are also useful for studies of the normal morphology of neural tissue. For example, bisbenzimide and nuclear yellow at low concentrations produce a brilliant Nissl stain at pH 2, and stain only nuclei at pH 7.2. The latter procedure may be particularly useful for cell counts. Finally, neutral red, astrazone red, and safranin-O differentially stain cells amd myelinated fibers, producing fluorescence analogs of the Klüver-Barrera stain.
已开发出对含有荧光标记的神经组织进行复染的方法。吖啶橙可用于定位用荧光示踪剂真蓝、双苯甲酰胺和核黄逆行标记的细胞，因为在低浓度下，当用蓝光而非紫外光激发时，它会产生绿色尼氏染色；由于示踪剂仅在暴露于紫外光时才会发出荧光，它们不会被复染剂掩盖。此外，在pH 2条件下复染可显著增加双苯甲酰胺的荧光。溴化乙锭可用于免疫组织化学（IHC），因为当用绿光激发时，它会产生明亮的红色尼氏复染，而当荧光素标记物用蓝光激发或使用紫外激发时，它仅微弱可见。因此，溴化乙锭也是荧光逆行示踪剂以及IHC-逆行示踪剂联合研究的良好复染剂。某些染料也可用于神经组织正常形态的研究。例如，低浓度的双苯甲酰胺和核黄在pH 2时会产生明亮的尼氏染色，而在pH 7.2时仅对细胞核染色。后一种方法可能对细胞计数特别有用。最后，中性红、阿斯特拉宗红和番红O可对细胞和有髓纤维进行差异性染色，产生类似克吕弗-巴雷拉染色的荧光。
