RGD Reference Report - Increased catechol-O-methyltransferase activity and protein expression in OX-42-positive cells in the substantia nigra after lipopolysaccharide microinfusion. - Rat Genome Database

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Increased catechol-O-methyltransferase activity and protein expression in OX-42-positive cells in the substantia nigra after lipopolysaccharide microinfusion.

Authors: Helkamaa, T  Reenila, I  Tuominen, RK  Soinila, S  Vaananen, A  Tilgmann, C  Rauhala, P 
Citation: Helkamaa T, etal., Neurochem Int. 2007 Nov-Dec;51(6-7):412-23. Epub 2007 May 6.
RGD ID: 2289732
Pubmed: PMID:17573159   (View Abstract at PubMed)
DOI: DOI:10.1016/j.neuint.2007.04.020   (Journal Full-text)

Activated microglial cells are found in the substantia nigra and the striatum of Parkinson's disease patients. These cells have been shown to express catechol-O-methyltransferase activity which may increase during pathological conditions. Lipopolysaccharides are potent activators of microglial cells. After paranigral lipopolysaccharide infusion to rats we observed intense microglial activation around the lesion area followed by a delayed injury in nigrostriatal pathway in 2 weeks. Simultaneously, catechol-O-methyltransferase activity in the substantia nigra was gradually increased up to 213%. In the Western blot the amount of soluble COMT and membrane bound COMT proteins were increased by 255% and 86%, respectively. Increased catechol-O-methyltransferase immunoreactivity was located primarily into the activated microglial cells in the lesion area. Interestingly, catechol-O-methyltransferase and OX-42 stained also intensively microglia/macrophage-like cells which surrounded the adjacent blood vessels. Inhibition of catechol-O-methyltransferase activity by tolcapone or entacapone did not increase lipopolysaccharide-induced neurotoxicity. We conclude that catechol-O-methyltransferase activity and protein expression were increased in the substantia nigra after inflammation induced by lipopolysaccharides. These changes in glial and perivascular catechol-O-methyltransferase activity may have clinical relevance for Parkinson's disease drug treatment due to increased metabolism of levodopa in the brain.

Gene Ontology Annotations    Click to see Annotation Detail View

Biological Process
TermQualifierEvidenceWithReferenceNotesSourceOriginal Reference(s)
response to lipopolysaccharide  IEP 2289732 RGD 

Objects Annotated

Genes (Rattus norvegicus)
Comt  (catechol-O-methyltransferase)


Additional Information