| Autor: |
Damier, Philippe, Kastner, Anne, Agid, Yves, Hirsch, Etienne C. |
| Zdroj: |
Neurology (Ovid); May 1996, Vol. 46 Issue: 5 p1262-1269, 8p |
| Abstrakt: |
Evidence supports the role of hyperoxidation phenomena in the mechanism of nerve cell death in Parkinson's disease (PD). The oxidative degradation of dopamine, catalyzed by monoamine oxidase type B (MAO-B), produces free radicals and thus could be implicated in the degenerative process. For this reason, we investigated by immunohistochemistry the distribution of MAO-B-containing cells in the midbrain of five patients with PD and five matched control subjects. MAO-B-like immunoreactivity was detected in glial cells, fibers, and neurons. Although most of the MAO-B-positive neurons probably belonged to the raphe dorsalis, we demonstrated by double-labeling immunohisto-chemistry that some of them were also dopaminergic. MAO-B-positive dopaminergic neurons were present in all dopa-minergic groups of the control midbrain. Within the substantia nigra pars compacta, most dopaminergic neurons were located in the dorsal part of the structure. MAO-B-positive dopaminergic neurons were still detected in PD midbrains. Compared with control subjects, the loss of dopaminergic neurons containing MAO-B (−45) was no higher than that of MAO-B-negative dopaminergic neurons (−59). The density of MAO-B-positive glial cells varied in the control midbrains: high in the least affected dopaminergic group (the central gray substance) and low in the most affected region (the substantia nigra pars compacta). The density of MAO-B-positive glial cells within dopaminergic cell subgroups in control midbrains were negatively correlated (r = −0.94; p<0.02) to the estimated neuronal loss in PD. We conclude that the presence of MAO-B in dopamine-containing neurons does not contribute to vulnerability in PD. Moreover, its presence in some glial cells might have a protective effect against oxidative stress induced by dopamine metabolism. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
