CN19 decreases synaptic transmission in an NMDAR-independent way. CA1 neurons from hippocampal slice culture were transfected to overexpress GFP-CN19 for 2 d. Cell-pair recordings were performed from a transfected neuron and a nearby untransfected neuron. A, AMPAR EPSCs were significantly decreased by the overexpression of GFP-CN19 (average ± SEM: 128.7 ± 26.2 vs 50.6 ± 7.8 pA for untransfected and transfected cells, respectively; n = 11, *p = 0.013 with paired Student's t test). B, Slices were incubated in 100 μm APV after transfection for 2 d, and AMPAR EPSCs were recorded with APV removed. CN19 still significantly decreased AMPAR EPSCs after APV treatment (117.0 ± 26.9 vs 28.7 ± 6.6 pA for untransfected and transfected cells, respectively; n = 10, *p = 0.017 with paired Student's t test).