ACh causes insertion of AMPARs in dendritic spines. A, Images of representative spines, expressing GluR1-SEP (top), GluR2-SEP (bottom), and t-dimer red protein, before (Control) and after ACh. Scale bar, 1 μm. Note the increase in the yellow signal 30 min after application of ACh in both GluR1- and GluR2-expressing spines without changes in spine volume. B, Summary data showing the ACh effect on the content of GluR1 (black circles; n = 145 spines, 8 cells; p < 0.001) and GluR2 (white circles; n = 75 spines, 6 cells; p < 0.01) on the spines.