Osteopontin (Eta-1) is present in the rat basal ganglia

Osteopontin (OPN) is a secreted glycosylated phosphoprotein that is responsive to oxidative stress and inflammation and controls cytokine production, inducible nitric oxide synthase (iNOS) expression and apoptotic cell death. In this study, we demonstrate the presence of OPN in the rat basal ganglia. Using reverse transcriptase polymerase chain reaction (RT-PCR), OPN cDNA was found in the substantia nigra, and striatum. The presence of OPN mRNA was demonstrated in the same areas of the basal ganglia, using in situ hybridisation. OPN protein was found in the SN, using Western blotting and confirmed by immunohistochemistry. The protein was localised to neurones but not to microglia or astroglia. This is the first report of the presence of OPN in the basal ganglia where it may be involved in the maintenance of neuronal viability.