Figure 6

IVM-induced reduction of neuron firing and excitability in Rosa26-IVMR mice. (a) Neuron firing in the hippocampus of Rosa26-IVMR;Emx1-Cre mice is reduced after systemic administration of IVM. A significant reduction of neuron firing is present at 8 h, and it reaches the lowest level at 12 h and persists at 1 d. Recording was performed in free moving mice; 19 neurons from 4 wild type mice and 18 neurons from 2 Rosa26-IVMR;Emx1-Cre mice were included. *P < 0.05, **P < 0.01, ***P < 0.001, one-way ANOVA. Recordings from two reparative neurons in channel 3 and 7 are shown in the right panel. (b) Cortical neuron excitability shown by ratio of current threshold before and after IVM treatment is reduced in Rosa26-IVMR;Emx1-Cre mice after bath application of IVM, whereas it was unchanged in wild type mice. n = 7 for wild type, n = 8 for Rosa26-IVMR;Prrxl1-Cre^ER mice; *P < 0.05; 2-tailed Student's t-test. (c) Time course of action potential frequency initiated by injection of current (450 pA, 400 ms) after bath application of IVM (10 nM, 3 min). Action potential frequency was normalized to that obtained before IVM treatment for comparison. Note that the frequency of action potential decreased rapidly and dramatically after IVM treatment. n = 6 for wild type, n = 5 for Rosa26-IVMR;Prrxl1-Cre^ER mice. *P < 0.05, **P<0.01, ***P < 0.001; two-way repeated ANOVA test.