Allard M, Caillé J M, Bonnemain B, Meyer D, Simonnet G
Department of Neuroradiology, Groupe Hospitalier Pellegrin-Tripode, Bordeaux, France.
Acta Radiol Suppl. 1986;369:572-4.
Gadolinium complexes have two advantages: their toxicity is very low and the paramagnetic properties are adequate enough to give a useful signal with magnetic resonance imaging (MRI). The effects of several MRI contrast media on the activity of two brain enzymes, glutamate decarboxylase (GAD) and cholineacetyl transferase (ChAT), were investigated. The study was performed on homogenates of rat striatum with variable concentrations of gadolinium sulphate, EDTA, DTPA, DOTA, Gd-EDTA, Gd-DTPA and Gd-DOTA (from 10(-2) mol/l to 10(-9) mol/l. Gadolinium in its ionic form and the chelators of cation agents such as EDTA, DTPA and DOTA inhibit GAD, a calcium dependent enzyme, whereas they have no inhibiting effect on the activity of ChAT, a calcium independent enzyme. Gadolinium complexes inhibit the GAD activity by about 15 per cent whereas they do not modify that of ChAT. The complex form of gadolinium has the advantage of retaining its paramagnetism while drastically lowering its toxicity.
它们的毒性非常低，并且其顺磁性足以在磁共振成像（MRI）中产生有用的信号。研究了几种MRI造影剂对两种脑酶，即谷氨酸脱羧酶（GAD）和胆碱乙酰转移酶（ChAT）活性的影响。该研究在含有不同浓度硫酸钆、乙二胺四乙酸（EDTA）、二乙三胺五乙酸（DTPA）、四氮杂环十二烷四乙酸（DOTA）、钆-乙二胺四乙酸（Gd-EDTA）、钆-二乙三胺五乙酸（Gd-DTPA）和钆-四氮杂环十二烷四乙酸（Gd-DOTA）（浓度范围为10⁻²摩尔/升至10⁻⁹摩尔/升）的大鼠纹状体匀浆上进行。离子形式的钆以及阳离子试剂的螯合剂如EDTA、DTPA和DOTA会抑制GAD（一种钙依赖性酶），而它们对ChAT（一种非钙依赖性酶）的活性没有抑制作用。钆配合物会使GAD活性降低约15%，而对ChAT活性没有影响。钆的配合物形式具有在大幅降低其毒性的同时保留其顺磁性的优点。
