Activation of cell-survival signal Akt by GDNF in normal rat brain

Glial cell line-derived neurotrophic factor (GDNF) activates protein kinase Akt/PKB by phosphorylation (p-Akt) which plays key roles in cell survival. In the current study, we investigated a temporal expression of p-Akt by immunohistochemical analysis after a topical application of GDNF to normal cerebral hemisphere of rats. Although p-Akt immunoreactivity was weakly present in the sham control neural cells, GDNF application greatly enhanced it at 3 h, which lasted until 1 day. These results indicate that p-Akt is expressed in neuronal cells under physiological conditions, and that topical application of GDNF greatly enhanced the phosphorylation of Akt in normal rat brain.