Increase of catechol-O-methyltransferase activity in rat brain microglia after intrastriatal infusion of fluorocitrate, a glial toxin.
Striatal catechol-O-methyltransferase (COMT), monoamine oxidase B (MAO-B; an astroglial enzyme), alkaline phosphodiesterase I (PDE; a microglia/macrophage marker) and tyrosine hydroxylase (TH; catecholaminergic neuron marker) activities were analyzed biochemically 1-3 days after infusion of fluorocitrate, an astrocyte damaging agent. Astrocytes, microglia and neurons were stained immunohistochemically with specific antibodies (against glial fibrillary acidic protein, OX-42 and TH, respectively) and with COMT antiserum. Three days after fluorocitrate infusion the activity of MAO-B was reduced, whereas COMT and PDE activities were increased. The elevation of COMT immunoreactivity co-localized to microglial cells, but not to astrocytes. In conclusion, this is the first report indicating that microglia contains COMT activity which may be increased in pathological conditions.
Reenilä
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Institute of Biomedicine, Department of Pharmacology and Toxicology, University of Helsinki, Finland. ilkka.reenila@helsinki.fi
Tuomainen
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Soinila
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Männistö
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D000818:Animals; D002394:Catechol O-Methyltransferase / Q000378:metabolism*; D002951:Citrates / Q000494:pharmacology*; D003342:Corpus Striatum / Q000166:cytology*; D003603:Cytotoxins / Q000494:pharmacology; D008297:Male; D017628:Microglia / Q000187:drug effects* / Q000201:enzymology*; D008845:Microinjections; D051381:Rats; D017208:Rats, Wistar
D002951:Citrates; D003603:Cytotoxins; C007744:fluorocitrate; D002394:Catechol O-Methyltransferase