a, Pharmacological activation of TRPV1 receptors with the agonist capsaicin (CAP, 1 µM) depresses AMPAR-EPSC in an input-specific manner. Top panel: Representative traces of two consecutive AMPAR-EPSCs (100 ms interstimulus interval) before (black) and after (gray) bath application of 1 µM CAP at both medial perforant path (MPP) and mossy cell fibers (MCF). Bottom panel: Summary plot showing the effect of CAP on AMPAR-EPSC. Application of the group II mGluR agonist DCG-IV (1 µM) selectively depressed MPP- but not MCF-EPSCs, and subsequent application of the AMPAR antagonist NBQX (10 µM) abolished the remaining DCG-IV insensitive component. b, Average traces (top panel) and summary data (bottom panel) showing that pre-treatment with the TRPV1 antagonist capsazepine (CPZ, 10 µM) or loading of DGCs with the antagonist AMG9830 (AMG, 3 µM) eliminates CAP-mediated depression of AMPAR-EPSC in the MPP. c, CAP-mediated depression of AMPAR-EPSC is also present in TRPV1+/+ but not TRPV1−/− mice. In all panels, averaged sample traces taken at times indicated by numbers are shown next to each summary plot. Number of cells (c) and animals (a) are indicated in parentheses. Summary data consist of mean ± s.e.m.