Lindvall O, Björklund A, Falck B, Lorén I
Histochemistry. 1980;68(2):169-81. doi: 10.1007/BF00489512.
The fluorophore and fluorescence yield from tryptamine and 3-methoxytyramine in histochemical protein models have been compared in the standard formaldehyde reaction, the acid-catalyzed formaldehyde reaction, the formaldehyde-ozone reaction, and the aluminum-formaldehyde reaction. In the standard formaldehyde reaction both the fluorophore and fluorescence yields are low. However, the other reactions give a dramatic increase in fluorescence intensity (18-20 times) from tryptamine and 3-methoxytyramine whereas only minor changes (up to 100% increase) in fluorophore yield are observed. It is concluded that the relative fluorescence intensity of each fluorophore molecule formed in the three modifications of the formaldehyde reaction is much higher than that of the molecules formed in the standard formaldehyde reaction. It has previously been demonstrated that the fluorophores formed from dopamine in the gaseous formaldehyde and glyoxylic acid reactions have a much higher (10 times) relative fluorescence intensity than the synthetic fluorophores. the prresent experiments show that if the histochemicl models are dissolved in buffer after the reaction and new models are made from this solution, the fluorescence intensity of the fluorophores formed in the reaction is drastically reduced and becomes comparable to that of the synthetic ones. The results of this and our previous studies indicate that hitherto unknown fluorescence enhancing mechanisms play a major role for the fluorescence yield, i.e. the sensitivity, in the various formaldehyde and glyoxylic acid methods. One possible explanation to the high relative fluorescence intensity of the fluorophores formed in the histochemical reactions could be an energy transfer between, e.g. the non-fluorescent intermediary reaction products (the tetrahydro derivatives) and the fluorophores (the dihydroisoquinolines and dihydro-beta-carbolines). Such an energy transfer is probably attenuated in the dissolved models, where th distances betweenm and orientations of the various molecules have been changed.
在标准甲醛反应、酸催化甲醛反应、甲醛 - 臭氧反应和铝 - 甲醛反应中，对色胺和3 - 甲氧基酪胺在组织化学蛋白质模型中的荧光团和荧光产率进行了比较。在标准甲醛反应中，荧光团和荧光产率都很低。然而，其他反应使色胺和3 - 甲氧基酪胺的荧光强度显著增加（18 - 20倍），而荧光团产率仅观察到微小变化（最多增加100%）。得出的结论是，在甲醛反应的三种变体中形成的每个荧光团分子的相对荧光强度远高于在标准甲醛反应中形成的分子。先前已经证明，在气态甲醛和乙醛酸反应中由多巴胺形成的荧光团的相对荧光强度比合成荧光团高得多（10倍）。目前的实验表明，如果在反应后将组织化学模型溶解在缓冲液中，并从该溶液制备新的模型，反应中形成的荧光团的荧光强度会急剧降低，并变得与合成荧光团的荧光强度相当。本研究和我们先前研究的结果表明，迄今未知的荧光增强机制在各种甲醛和乙醛酸方法中对荧光产率（即灵敏度）起主要作用。对组织化学反应中形成的荧光团的高相对荧光强度的一种可能解释可能是例如非荧光中间反应产物（四氢衍生物）和荧光团（二氢异喹啉和二氢 - β - 咔啉）之间的能量转移。在溶解的模型中，这种能量转移可能会减弱，因为各种分子之间的距离和取向已经改变。
