Figure 2

Astrocytic glutamate released upon PAR1 activation induces NMDAR-dependent enhancement of basal EPSP responses at SC-CA1 synapses via the Best1 channel. A, Schematic diagram showing whole-cell patch clamp measurement of eEPSPs upon Schaffer collateral (Sch) stimulation recorded from hippocampal CA1 pyramidal neurons (CA1). 30 μM of TFLLR was applied via the bath solution to induce Ca²⁺-dependent glutamate release from CA1 astrocytes. A surgical cut was made between CA3 and CA1 (CA3-CA1 cut). DG, dentate gyrus. B, Representative eEPSP traces recorded from CA1 neurons in naïve slices or slices expressing Best1-shRNA in astrocytes. Black, before TFLLR application; red, 15 min after TFLLR application. C, Amplitudes of eEPSPs from each recording were normalized to the mean amplitude of baseline period prior to TFLLR application and shown as averaged relative eEPSPs ± s.e.m. (% Baseline). Graphs represent eEPSP responses recorded from hippocampal slices of wild type mice treated with control solution (wild type, empty circles) or APV-containing solution (+APV, black circles), and hippocampal slices of Best1 knockout mice treated with control solution (Best1 KO, grey circles). D, Bar graph representing mean relative eEPSPs (mean ± s.e.m), analyzed during the period covered by the gray box in C. Bar colors correspond to colours in C. **, P < 0.01, one-way ANOVA with post-hoc test.