Kalaria R N, Mitchell M J, Harik S I
Department of Neurology, University Hospital of Cleveland, Ohio 44106.
Brain. 1988 Dec;111 ( Pt 6):1441-51. doi: 10.1093/brain/111.6.1441.
The two molecular forms of monoamine oxidase (MAO), MAO-A and MAO-B, were determined quantitatively in discrete regions of the human brain at autopsy, and in cerebral microvessels, choroid plexus and liver samples from the same subjects. MAO was assessed by specific[3H] pargyline binding, which is stoichiometric and irreversible, and by measuring the rate of oxidation of several MAO substrates. Basal ganglia structures (caudate, putamen, globus pallidus and substantia nigra) and hippocampus had about twice the levels of MAO that were present in the cerebral cortex and cerebellum. Cerebral microvessels, which constitute the blood-brain barrier, had minimal MAO, while the choroid plexus, which constitutes the blood-cerebrospinal fluid barrier, and the liver had higher MAO levels than any brain region. The vast majority of MAO (80-95%) in these tissues was of the B type, except in microvessels, where total MAO activity was low. Specific [3H]pargyline binding correlated well with the oxidation rates for 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and benzylamine in all tissues. Both specific [3H]pargyline binding and the rate of oxidation of MAO substrates increased with age.
在尸检时对人脑的离散区域以及来自同一受试者的脑微血管、脉络丛和肝脏样本中，对单胺氧化酶（MAO）的两种分子形式MAO - A和MAO - B进行了定量测定。MAO通过特异性的[³H]帕吉林结合（这是化学计量且不可逆的）以及测量几种MAO底物的氧化速率来评估。基底神经节结构（尾状核、壳核、苍白球和黑质）和海马体中的MAO水平约为大脑皮层和小脑中MAO水平的两倍。构成血脑屏障的脑微血管中MAO含量极少，而构成血脑脊液屏障的脉络丛以及肝脏中的MAO水平高于任何脑区。这些组织中绝大多数MAO（80 - 95%）为B型，除了微血管，其总MAO活性较低。在所有组织中，特异性的[³H]帕吉林结合与1 - 甲基 - 4 - 苯基 - 1,2,3,6 - 四氢吡啶和苄胺的氧化速率相关性良好。特异性的[³H]帕吉林结合以及MAO底物的氧化速率均随年龄增长而增加。
