Youdim M B
Rappaport Family Research Institute, Technion, Haifa, Israel.
Experientia. 1988 Feb 15;44(2):137-41. doi: 10.1007/BF01952197.
The human platelet in addition to having serotonin (5-HT) receptors, uptake carriers (receptor) and transmitter storage vesicles, primarily possesses mitochondrial monoamine oxidase (MAO) type B. Similar to the major form of MAO in the human brain, this enzyme actively oxidizes A-B and B substrates (tyramine, dopamine, phenylethylamine) as well as the novel secondary amine anticonvulsant, milacemide and dopaminergic neurotoxin, MPTP. 5-HT oxidation is hardly affected by the platelet enzyme and MAO inhibitors have no net effect on its accumulation. MAO-B is selectively inhibited by 1-deprenyl and thus the platelet enzyme may be useful to monitor the anti-Parkinson activity of such drugs, as related to their ability to inhibit brain MAO-B. The oxidation of the anticonvulsant, milacemide, to glycine in vitro and in vivo by MAO-B, may herald new prospects for the development of inert prodrugs capable of being metabolized to neuroactive substances by MAO-B. The plasma levels of their metabolites may be an index of MAO-B activity found in the platelet and brain.
人类血小板除了具有5-羟色胺（5-HT）受体、摄取载体（受体）和递质储存囊泡外，主要还拥有B型线粒体单胺氧化酶（MAO）。与人类大脑中MAO的主要形式相似，这种酶能积极氧化A-B和B底物（酪胺、多巴胺、苯乙胺）以及新型仲胺抗惊厥药米拉醋胺和多巴胺能神经毒素MPTP。5-HT的氧化几乎不受血小板酶的影响，MAO抑制剂对其积累也没有净效应。MAO-B可被司来吉兰选择性抑制，因此血小板酶可能有助于监测此类药物的抗帕金森活性，这与其抑制脑MAO-B的能力有关。MAO-B在体外和体内将抗惊厥药米拉醋胺氧化为甘氨酸，这可能为开发能够被MAO-B代谢为神经活性物质的惰性前药带来新的前景。它们代谢物的血浆水平可能是血小板和大脑中MAO-B活性的一个指标。
