Fig. 2.

The effect of 5-HT on the induction of LTP in the white matter-layer II/III pathway in the visual cortex slices obtained from 3-week-old rats. A, Time course of LTP. Tetanic stimulation was applied in the absence (○) or presence (●) of 10 μm 5-HT. 5-HT was added during the time indicated by thehorizontal bar (−20 to 10 min). Insetsare sample records at the times denoted by the numbers. Calibration: vertical, 0.3 mV; horizontal, 5 msec. B, Concentration-dependent effect of 5-HT. The average of the percentage amplitude of synaptic potentials 30–60 min after tetanic stimulation was calculated to compare the magnitude of LTP in each group. Data are the means ± SEM (n = 5). **p < 0.01 versus control group; Tukey's test after ANOVA.