四甲基联苯胺—钨酸钠(TMB-ST)反应产物的后处理方法研究

在大白鼠尾壳核-黑质投射模型上,研究了不同pH的DAB-硫酸镍铵或DAB-钴对TMB-钨酸钠(TMB-ST)反应产物的后处理效果。结果发现,用高pH的DAB-硫酸镍铵温育是TMB-ST反应产物的一种较好的后处理步骤,它使TMB-ST反应产物完全转变为蓝黑色,能耐受pH 7.4的环境,并增加反应产物的嗜锇性和电子密度,而反应液很少出现非特异性沉淀。可是,与DAB-钴处理类似,它也导致TMB-ST成色法的灵敏度下降,两者引起的下降程度也很接近。根据对DAB-钴后处理的研究,TMB-ST成色法在用DAB-重金属离子处理后,其灵敏度仍接近未经任何处理的Mesulam 的TMB法。用 Hancock 的DAB-硫酸镍铵反应液(pH 6.0)作为TMB-ST反应产物的后处理方法则没有成功。本文还讨论了DAB-重金属离子溶液对TMB反应产物起稳定作用的机制,认为与TMB反应产物的不稳定性以及重金属离子引起DAB的非酶氧化有关。

The Study on the Posttreating Procedures for the Tetramethylbenzidine-Sodium Tungstate(TMB-ST)Reaction Product

In this paper,the comparison of the various DAB-metal posttreating procedures for TMB-sodium tungstate(TMB-ST)method was performed in the caudate- putamen-substantia nigra projection model of the rat.Best results were obtained by the posttreating procedure with DAB/nickle ammonium sulfate/H_2O_2(DAB-Ni) mixture in high pH medium(pH 7.4).Its resultant reaction product is all blue-black coloured,stable in pH 7.4 medium,and electron-dense in electron microscopical level. Moreover,this procedure dose hardly produce the nonspecific precipitate that often appear in the Rye's DAB-cobalt(DAB-Co)step('84).However,the DAB-Ni procedure also reduce the sensitivity of the original TMB-ST method as much as the DAB-Co step. Although the sensitivity decreases,the sensitivity of TMB-ST method posttreated with DAB-Co step is still similar to original Mesulam's TMB method.The results also showed that an other DAB-Ni step using Hancock's reaction medium(pH 6.0)can not be adapt to posttreat the TMB-ST reaction product.The mechanism of stabilizing TMB reaction product with DAB metal ion solution was discussed.