Sigma receptors (σRs), which are classified into three subtypes (σR1, σR2, σR3), are widely distributed in the central nervous system.Our previous studies showed that σR1 was expressed in most of rat inner retinal neurons, including ganglion cells (GCs) and activation of σR1 suppressed NMDA receptor-mediated currents of GCs.Nevertheless, whether and how σR1 is involved in signal processing of GCs are still largely unknown.In the present work, using patch-clamp whole-ceil recording we investigated how activation of σR1 modulates light-evoked excitatory postsynaptic currents (eEPSCs) of GCs in rat retinal slice preparations.Bath application of the σR1 agonist SKF10047 (SKF) suppressed NMDA receptor-mediated eEPSCs at different holding potentials in ON, OFF and ON-OFF GCs, and the effects were blocked when the preparations were pre-incubated with the σR1 antagonist BD1047.