Activation of the GDNF/GFRα-1 signaling pathway contributes to Rheb(S16H)-induced neuroprotection in the hippocampus. Rats received an AAV injection, and then immunohistochemical staining for NeuN was performed to count the number of preserved neurons in the CA1 regions of the hippocampus at 7 days after treatment with thrombin (Thr.; 20 U) and neutralizing antibodies (NA; 200 ng) against GDNF, GFRα-1, or BDNF, or thrombin alone (). Right panels are magnified photomicrographs of the rectangular insets in the CA1 layer. Scale bars: left column, 500 μm; right column (insets), 100 μm. The number of NeuN-positive hippocampal neurons in each CA1 layer was quantitatively expressed as a percentage compared to that of the contralateral control. Differences among groups were evaluated by one-way analysis of variance and Tukey’s post-hoc analysis; [*p<0.001, ^#p<0.001, and ^$p<0.05 vs. CON, thrombin alone, Rheb(S16H)+thrombin, respectively; n=3 per group].