Yanev S, Grahovska T, Kadiiska M, Stoytchev T
Acta Physiol Pharmacol Bulg. 1984;10(3):36-45.
In in vivo and in vitro experiments the effects of some heavy metal salts (Cu, Co, Cd, Pb, Ni, Zn, Hg, As, Bi and Sn) on rat liver and brain mitochondrial monoamine oxidase (MAO) activity was studied using three different substrates (tyramine, 5-hydroxytryptamine (5-HT) and beta-phenylethylamine (2-PEA). It was established that some of the metals (Cu, Cd, Bi) inhibited MAO activity both in vivo and in vitro experiments, others like Ni, Zn, As and Sn inhibited it only in vivo while Hg exerted inhibitory action only in vitro. The in vivo experiments showed significantly higher sensitivity of brain MAO as compared with liver MAO to the inhibitory action of metals. The same higher susceptibility was shown by liver and brain MAO-A form. It was concluded that the inhibitory effects of some heavy metal salts on MAO activity were not directly connected with their action on enzyme thiol groups but more probably with changes in the enzyme membrane surroundings in the different organs.
在体内和体外实验中，使用三种不同的底物（酪胺、5-羟色胺（5-HT）和β-苯乙胺（2-PEA））研究了某些重金属盐（铜、钴、镉、铅、镍、锌、汞、砷、铋和锡）对大鼠肝脏和脑线粒体单胺氧化酶（MAO）活性的影响。结果表明，某些金属（铜、镉、铋）在体内和体外实验中均抑制MAO活性，而镍、锌、砷和锡等其他金属仅在体内抑制MAO活性，汞仅在体外发挥抑制作用。体内实验表明，与肝脏MAO相比，脑MAO对金属抑制作用的敏感性显著更高。肝脏和脑MAO-A形式也表现出相同的更高敏感性。得出的结论是，某些重金属盐对MAO活性的抑制作用与其对酶硫醇基团的作用没有直接关系，而更可能与不同器官中酶膜环境的变化有关。
