Figure 4. Sparse excision of PirB from PirBfl/fl at E15.5 increases mEPSC frequency but not amplitude in L2/3 pyramidal neurons in P30 visual cortex. A, C, Combined differential interference contrast and fluorescence micrographs of neurons in visual cortex used for whole-cell recordings of mEPSCs, showing GFP
–;Cre− cells (A) and an isolated GFP+;Cre+ cell (C). B, D, Example mEPSC traces from GFP−;Cre− (B) or GFP+;Cre+ (D) L2/3 pyramidal neurons from primary visual cortex slices of P30 PirBfl/fl mice. E, Fluorescent micrograph showing an L2/3 pyramidal neuron filled with biocytin during mEPSC recording, and visualized with Texas Red-conjugated avidin. F, Zoomed-in, maximum-intensity projection of the boxed area in E, showing apical dendritic spines. G, In PirBfl/fl mice, mEPSC frequency is increased in GFP+;Cre+ cells compared with GFP−;Cre− cells (GFP−;Cre−: 16.91 ± 2.28 Hz, n = 17 cells, 14 slices, 8 mice; GFP+;Cre+: 28.51 ± 2.89 Hz, n = 22 cells, 14 slices, 8 mice; p = 0.0058h, Mann–Whitney test). H, Cumulative histogram (by cell) of data presented in G. I, mEPSC amplitude does not differ between GFP−;Cre− and GFP+;Cre+ cells in PirBfl/fl mice (GFP−;Cre−: 13.18 ± 0.97 pA, n = 17, cells, 14 slices, 8 mice; GFP+;Cre+: 14.32 ± 0.64 pA, n = 22 cells, 14 slices, 8 mice; p = 0.3286i, Mann–Whitney test). J, Cumulative histogram (by cell) of data presented in I. K, In control PirB+/+ mice, electroporation of GFP.Cre did not result in an increase in mEPSC frequency in GFP+;Cre+ relative to GFP−;Cre−, as expected (GFP−;Cre−: 12.53 ± 2.55 Hz, n = 11 cells, 11 slices, 6 mice; GFP+;Cre+: 15.01 ± 2.76, n = 13 cells, 11 slices, 6 mice; p = 0.4940j, Mann–Whitney test). L, Cumulative histogram of data presented in K. M, In control PirB+/+ mice, mEPSC amplitudes are not different between GFP+;Cre+ and GFP−;Cre− cells (GFP−;Cre−: 11.28 ± 1.26 pA, n = 11 cells, 11 slices, 6 mice; GFP+;Cre+: 9.73 ± 0.69, n = 13 cells, 11 slices, 6 mice; p = 0.3918k, Mann–Whitney test). N, Cumulative histogram of data (by cell) presented in M. Scale bars: A, C, 25 μm; E, 20 μm; F, 5 μm. **p < 0.01.