(A–C) Whole-cell data from cerebellar granule cells. AMPA receptor-mediated spontaneous EPSCs were not observed in cerebellar granule cells from stargazer mice and in stargazer cerebellar granule cells transfected with GFP alone (MOCK) (n=4) (N.D. not detectable). The expression of GluR4i with stargazin (STG) (black) or GluR4i-STG tandem (red) rescued synaptic transmission in neurons from stargazer mice. The amplitude (A, B) and decay (B, C) of spontaneous EPSCs in stargazer granule cells transfected with GluR4i with stargazin or GluR4i-stargazin tandem were not significantly different (n=6). (D, E) Whole-cell paired recordings from primary cultured hippocampal neurons. Neurons were transfected with cDNAs encoding GFP alone, GFP with GluR4i and stargazin, GFP with GluR4i-stargazin tandem. Transfected neurons were identified by GFP expression. Putative pairs of morphologically connected neurons were identified visually and both neurons were patched simultaneously. Once synaptic connectivity was confirmed, pairs of 1 ms jumps −70 mV to + 20 mV were applied to the presynaptic neuron at an interval of 20 ms. Neurons expressing GFP alone (MOCK) and with GluR4i and stargazin showed paired pulse depression, whereas paired pulse facilitation was observed in neurons expressing GFP and the GluR4i-stargazin tandem (n=4–6). (**: P < 0.01, one-way ANOVA). The evoked EPSCs were blocked by the addition of AMPA receptor antagonist CNQX (100μM, red traces in D). All data represent the mean ± s.e.m.