Figure 3.
Strong LTD induced by two bouts of LFS is resistant to reversal. A, LTD induced by two bouts of LFS (1200 pulses, 3 Hz; n = 7) each separated by 5 min. B, D1/D5R receptor activation by SKF 38393 (100 μm, 20 min; n = 10), applied immediately after the second bout of LFS, failed to significantly reverse the LTD after 120 min (p = 0.06). C, LFS-induced LTD is NMDAR dependent. NMDAR blockade by APV (50 μm; n = 5) during LFS blocked LTD induction. After APV washout, LTD could again be induced by LFS. D, Histogram comparing LTD recorded in control slices 60 min after two bouts of LFS with that recorded in slices treated with APV (50 μm), SKF 38393 (SKF; 100 μm, 20 min), isoproterenol (ISO; 1 μm, 20 min; n = 5), or forskolin (FSK; 10 μm, 20 min; n = 5). No significant reversal of LTD was observed in any group. Waveforms are as in Figure 1.