<p>(A) Effect of J147 (1 µM) on basal synaptic transmission. Hippocampal slices were exposed to J147 during the time indicated by the black bar. The fEPSP slope is expressed as the percentage of the value immediately before the addition of J147. J147 does not affect basal synaptic transmission. (B) J147 facilitates the induction of LTP after a weak tetanic stimulation (15 pulses at 100 Hz) which alone does not induce LTP in control slices. The effect of J147 is concentration-dependent. Time course of changes in the fEPSP slope. The hippocampal slices were untreated (o, n = 9) or exposed to J147 (▾, 0.01 µM, n = 6; ▴, 0.1 µM, n = 5; •, 1 µM, n = 7) for the time indicated by the black bar and weak tetanic stimulation was applied at time 0. The fEPSP slope is expressed as the percentage of the value immediately before the application of weak tetanic stimulation. (C) Concentration-dependency. To compare the data among the groups, the averages of the fEPSP slopes 30–60 min after tetanic stimulation were calculated as an index of LTP magnitude. J147 demonstrated a concentration dependent effect with 1000 nM having the greatest effect on the fEPSP slope (n = 7 slices per rat: one-way ANOVA F(3,23) = 4.4, **<i>P</i> = 0.01). (D) Negative Control. −187–88, the alkene form of J147 in which nitrogens are replaced by carbons (o, n = 9; ▴, 0.1 µM, n = 5; •, 1 µM, n = 5) showed no effect. All data shown are means ± SEM.</p
