Figure 3. Population spike (PS) amplitudes (percentage change from baseline values) over 8 hr and a 24 hr value for rats that were handled 15 min after tetanus and injected with a GR-antagonist (A) (n = 6; p = 0.005, 0.004, 0.013, 0.001, 0.012, 0.002, 0.003, 0.001, 0.013, levels for increasing time points) or an MR-antagonist (B) compared with vehicle-treated rats. Rats that experienced a 2 min swim after tetanus and injection of a GR-antagonist showed no differences compared with vehicle-treated rats (C), whereas injection of an MR-antagonist impaired LTP (D) (p = 0.007, 0.007, 0.0001, 0.0001, 0.0001, 0.0001, 0.0001, 0.0001, levels for increasing time points). E, Injection of a mixture of GR-MR-antagonists also impaired LTP (p = 0.008, 0.0001, 0.0001, 0.0001, 0.0001, 0.0001, 0.001, 0.001, levels for increasing time points). F, Baseline control groups were used for both antagonists. Means ± SEM are given. Asterisks indicate significant time point differences. The diagram insets show representative analog traces for GR-ant-treated rats (A) and MR-ant treated rats (D) at the indicated time points. Dashed lines indicate the 100% level.