Figure 3.
Application of PARP inhibitors during 5-HT treatment blocks 24 h LTF. PARP inhibitor 3AB (A) or PJ34 (B) blocks 24 h LTF when the drug is applied during 5-HT applications. A, B, Left, EPSPs were recorded in L7 before (Pre) and 24 h after (Post) 5-HT. Incubation with either 3AB (3AB + Cont) or PJ34 (PJ34 + Cont) did not affect synaptic baseline. Applications of 5-HT produced a significant change in EPSP amplitude that was blocked when 5-HT was applied in the presence of drug (3AB + 5-HT and PJ34 + 5-HT). Vertical bar, 20 mV; horizontal bar, 25 ms. Right, The histograms indicate that blocking PARP activity with either 3AB or PJ34 blocked LTF at 24 h. The height of each bar is the average change + SEM in the EPSPs 24 h after the indicated treatments. The dashed line at 100% indicates no change in EPSP. ANOVA indicated an effect of treatment for both drugs (A: df = 2, 18; F = 13.872; p < 0.001; and B: df = 2, 13; F = 11.9; p < 0.002). Individual comparisons indicate that 3AB or PJ34 blocked LTF; 3AB + Cont was not significantly different from 3AB + 5-HT and PJ34 + Cont was not significantly different from PJ34 + 5-HT. In contrast, 5-HT produced significant increases in the EPSP compared with 3AB + Cont (F = 11.372, p < 0.01), 3AB + 5-HT (F = 9.336, p < 0.01), PJ34 + Cont (F = 8.316, p < 0.01), and PJ34 + 5-HT (F = 9.737, p < 0.01).