Figure 3.

hRheb(S16H) induces a hypertrophic effect without LTP impairment from the cytoarchitectural changes in the hippocampus. (a) Morphologic analysis of hippocampal neurons at 4 weeks after intrahippocampal injection of AAV-hRheb(S16H). The upper panel shows a representative coronal section of the hippocampus following Nissl staining by cresyl violet. The experimental side (EXP) injected with AAV-hRheb(S16H) shows an increase in the area of Nissl-positive neurons, compared to the contralateral control side (CON), as shown in representative micrographs at higher power in the lower panels. All pictures show the representative coronal section of each group (n = 5, each group). Bar = 500 μm (upper panel) and 20 μm (lower panel). (b) The area of Nissl-positive neurons in the CA1 layer. The area of neurons was expressed quantitatively as a percentage relative to the contralateral control. *P < 0.01, significantly different from CON and AAV-GFP (one-way analysis of variance and Student–Newman–Keuls analysis; n = 5, each group). WT, wild-type. (c) NeuN-positive neurons also show morphologic changes in the hippocampus at 4 weeks after injection of hRheb(S16H). (d) The number of the NeuN-positive neurons in the CA1 layer injected with viral vectors. Note that there is no difference between groups (one-way analysis of variance and Student–Newman–Keuls analysis; n = 5, each group). (e) Effect of hRheb(S16H) on the induction of LTP in the hippocampus. Hippocampal slices were prepared from the rats 3 weeks (n = 6) after injection of hRheb(S16H), and noninjected slices were used as controls (n = 6). The slices were perfused with artificial cerebrospinal fluid (ACSF) for 60 minutes. For the induction of LTP, the slices were tetanized with a 100 Hz for 1 second stimulation at time 0 minute. Note that there is no difference between the groups. Each point and line represents the mean ± SEM. Representative field excitatory postsynaptic potential (fEPSP) recordings at time −5 and 30 minutes are shown as insets (upper side).