Short-term and long-term plasticity in CA1. A, There were no significant differences in paired-pulse facilitation of fEPSPs between TRPV1-KO (filled circles) and TRPV1-WT (open circles) over a range of interstimulus intervals (ISI) between 20 and 300 ms. Insets show sample responses taken during paired-pulse stimulation for TRPV1-KO (black) and TRPV1-WT (gray). Calibration: 0.25 mV, 10 ms. B, Time course of field EPSPs evoked by test pulses (0.033 Hz, 20 μs) before and after an HFS (100 Hz/1 s, arrow). After induction of LTP, TRPV1-KO showed a significantly weaker LTP for at least 60 min after HFS. Insets show sample responses taken before (gray, 1) and after (black, 2) HFS for TRPV1-KO and TRPV1-WT. Calibration: 0.5 mV, 10 ms. For each genotype, a total of six brain slices obtained from four mice were analyzed. *p < 0.05.