DHPG increased the internalization of PSD95 with the lysosome marker CD68 in microglia in the hippocampal CA1of naïve rats (a, n = 5 rats in each group, unpaired-t test, t = 12.4, DF = 8, two-tailed P <0.0001, scale bar = 10 μm). Each dot represents the mean value of 4 brain sections of one rat. DHPG also decreased the amplitude (b, n = 15 rats in each group, unpaired-t test, t = 2.8, DF = 28, two-tailed P = 0.0084) and increased inter-event interval (b, n = 15 rats in each group, unpaired-t test, t = 2.8, DF = 28, two-tailed P = 0.0084) of mEPSCs in hippocampal CA1 neurons, and increased escape latency (c, n = 10 rats in each group, effect of group [F1,18 = 8.2, P = 0.01], effect of time [F4,18 = 82.8, P<0.0001], interaction between group and time [P = 0.52]), and decreased the time in the target quadrant (d, n = 10 rats in each group, F1,18 = 14.4, P = 0.001). (d) Representative path tracings in each quadrant during the probe trial on day 6 (T, target quadrant; R, right quadrant; O, opposite quadrant; L, left quadrant). Data represent mean ± s.e.m. For box-and-whiskers plots, the box extends from the 25th to 75th percentiles, a line within the box marks the median. Whiskers (error bars) above and below the box represent the minimum and maximum values. *P<0.05, **P<0.01, ***P<0.001.