Hersh L B, Aboukhair N, Watson S
Department of Biochemistry, University of Texas Health Science Center at Dallas 75235.
Peptides. 1987 May-Jun;8(3):523-32. doi: 10.1016/0196-9781(87)90019-2.
An antiserum specific for rat aminopeptidase M has been used for the immunohistochemical localization of the enzyme in rat brain and peripheral tissues. The enzyme in brain is localized exclusively on blood vessels. Within the pituitary the enzyme was associated with the vasculature in the posterior lobe, on the surface of the intermediate lobe and on the surface of some cells in the anterior lobe. In the liver, fine cell staining was observed between parenchymal cells, in the ileum the entire lumenal surface was stained, while in the kidney both proximal tubular and a central tubular staining was detected. In each tissue aminopeptidase M is localized such that it can limit diffusion across specific barriers. Aminopeptidase M activity in brain has been proposed to function in the degradation of synaptically released enkephalins. Its localization on blood vessels requires that enkephalins diffuse prior to degradation, a concept not in concert with current hypotheses. Based on these studies it is proposed that diffusion away from enkephalinergic synapses plays a key role in terminating enkephalin action.
一种针对大鼠氨肽酶M的抗血清已被用于该酶在大鼠脑和外周组织中的免疫组织化学定位。脑中的这种酶仅定位于血管。在垂体中，该酶与后叶的脉管系统、中间叶的表面以及前叶某些细胞的表面相关。在肝脏中，在实质细胞之间观察到细微的细胞染色，在回肠中整个管腔表面被染色，而在肾脏中则检测到近端小管和中央小管的染色。在每个组织中，氨肽酶M的定位使其能够限制跨特定屏障的扩散。有人提出脑中的氨肽酶M活性在降解突触释放的脑啡肽中起作用。它在血管上的定位要求脑啡肽在降解之前先扩散，这一概念与当前的假设不一致。基于这些研究，有人提出从脑啡肽能突触扩散在终止脑啡肽作用中起关键作用。
