Figure 1.

AMPARs with rapid kinetics mediate fast excitatory transmission between mitral and granule dendrites. (A₁) Paired whole-cell recording between a mitral and a granule cell (shown schematically at the top) in low Mg²⁺. Upper trace shows the voltage step (0 mV, 10 ms) applied to the mitral cell to evoke glutamate release. This generates a dual-component EPSC in the granule cell (Control). The fast component is abolished by the AMPAR antagonist (+NBQX, 10 μM), and the remaining slow component is blocked by an NMDAR antagonist (APV, 100 μM). (A₂) Digital subtraction of the response in NBQX from Control reveals the AMPAR EPSC fitted with a single exponential. (B) Current–voltage relationship for a granule cell AMPAR EPSC. (C) Granule cell AMPAR EPSC before (Control) and in the presence of cyclothiazide (CTZ, 200 μM). The EPSC in CTZ was abolished after application of NBQX.