Figure 7.

DHPG-induced mGluR-LTD is dependent on mTOR in hippocampal area CA1. A-D, mGluR-LTD was induced by incubation of slices with DHPG (50 μm) for 5 min in the presence of either vehicle, rapamycin (A, B), or ascomycin (C, D). Either vehicle or the inhibitors were present in the perfusing solution 10 min before, during, and 10 min after the treatment with DHPG, as indicated by the bars in each panel. A, Plotted are ensemble averages for the initial slope of the fEPSP for 20 min before, during, and 50 min after treatment of DHPG in the presence of either vehicle or rapamycin (20 nm). LTD was significantly inhibited by rapamycin as determined with a Student's t test (p < 0.0001) at the final time point (vehicle: closed squares; fEPSP slope, 76 ± 3% of baseline; n = 12; rapamycin: open squares; fEPSP slope, 92 ± 1% of baseline; n = 8). B, Representative fEPSPs before and 50 min after treatment with DHPG in the presence of either vehicle or rapamycin. C, Plotted are ensemble averages for the initial slope of the fEPSP for 20 min before, during, and 50 min after treatment of DHPG in the presence of either vehicle or ascomycin (20 nm). Ascomycin had no effect on LTD at the 50 min time point (vehicle: closed squares; fEPSP slope, 75 ± 4% of baseline; n = 8; ascomycin: open squares; fEPSP slope, 79 ± 6% of baseline; n = 4; p > 0.05 with a Student's t test). F, Representative fEPSPs before and 50 min after treatment with DHPG in the presence of either vehicle or ascomycin. Calibration: (B, D) 5 mV, 2 msec.