Expression of the glial cell line-derived neurotrophic factor gene in rat brain after transient MCA occlusion

Change of the glial cell line-derived neurotrophic factor (GDNF) gene expression in rat brain was examined after transient middle cerebral artery (MCA) occlusion of adult rats. Northern blot analysis showed that the mRNA began to be induced in the occluded MCA from 1 h of reperfusion with a peak at 3 h, and almost diminished by 1 day of reperfusion. Immunohistochemical analysis with brain sections showed an expression of GDNF-like immunoreactivity in neurons of the cerebral cortex and caudate after 90 min of ischemia in a similar way to the mRNA, but the staining was more disseminated and stronger in the cerebral cortex than the caudate. No glial cell was stained in the brain sections. The present results indicate that the GDNF gene was expressed in an early stage of reperfusion in neuronal cells of the MCA territory, but that the staining property was different between in the cerebral cortex and caudate.