Enkephalin Metabolism by Microglia Aminopeptidase N (CD13)
Version of Record online: 23 NOV 2002
Journal of Neurochemistry
Volume 64, Issue 4, pages 1841–1847, April 1995
How to Cite
Lucius, R., Sievers, J. and Mentlein, R. (1995), Enkephalin Metabolism by Microglia Aminopeptidase N (CD13). Journal of Neurochemistry, 64: 1841–1847. doi: 10.1046/j.1471-4159.1995.64041841.x
- Issue online: 23 NOV 2002
- Version of Record online: 23 NOV 2002
- Received June 6, 1994; revised manuscript received September 26, 1994; accepted September 26, 1994.
- Aminopeptidase N or M;
Abstract: Rat microglia in culture showed a high capacity to degrade neuropeptides compared with other glial cells. Leu-enkephalin was readily hydrolyzed to free tyrosine and Gly-Gly-Phe-Leu. Inhibition experiments and immunostaining revealed that aminopeptidase N (CD13) on the surface of microglia was responsible for enkephalin cleavage. Endopeptidase-24.11 (“enkephalinase”), angiotensin-converting enzyme, or carboxypeptidases could not be detected on microglia. Aminopeptidase N activity in microglia was considerably higher than in rat peripheral monocytes and macrophages, which both also exhibited low endopeptidase 24.11 activities. Activity of aminopeptidase N was upregulated by culture of microglia on astrocytes and downregulated by exposure of microglia to lipopolysaccharide. The occurrence of aminopeptidase N on microglia is in line with the view that they originate from the monocytic lineage.