Fig. 4

Compared to the adult rats, the protein expression levels of GDNF, GFR-α, and NRG-1 were significantly decreased in the aged group (a), whereas the protein expression levels of α7- and γ-nAChR were increased (b). The protein expression level of α7- and γ-nAChR was significantly increased in the aged rats. GDNF treatment decreased the protein expression of α7- and γ-nAChR but increased that of GFR-α and NRG-1 5 days postinjection (a and b). Values are shown as mean ± SD (n = 10, **P < 0.01)