Fig. 2: Selective enhancement of phasic and tonic inhibition onto interneurons by NG2 glia photostimulation.
From: NG2 glia-derived GABA release tunes inhibitory synapses and contributes to stress-induced anxiety
a Cartoon illustrating the anatomic location of cells for electrophysiology and photostimulations in CA1 region of the hippocampus at postnatal 4–6 weeks. b Representative traces (right panel) showing an increase of frequency but not the amplitude of mIPSCs from a whole-cell patched interneuron loaded with Alexa Fluor 568 in the patch pipette (left panel) after NG2 glia photostimulation in CA1 region. Scale bar, 20 μm. c and d Summary graphs for cumulative distributions of mIPSCs frequency and amplitude (c) and mean frequency and amplitude of mIPSCs (d) from recorded interneurons. n = 40 cells, two-tailed Wilcoxon-matched pairs test, P values as indicated. Note that the average of GABAARs kinetics in the inset shows no change after NG2 glia photostimulation. e Representative traces (right panel) showing no change of frequency and amplitude of mIPSCs of a whole-cell patched pyramidal neuron loaded with Alexa Fluor 568 in the patch pipette (left panel) after NG2 glia photostimulation in CA1 pyramidal cell layer. Scale bar, 20 μm. f and g Summary graphs for cumulative distributions of mIPSCs frequency and amplitude (f) and mean frequency and amplitude of mIPSCs (g) in recorded pyramidal neurons. n = 40 cells, two-tailed paired t test, n.s. indicates not significant. Note that the average of GABAARs kinetics in the inset shows no change after NG2 glia photostimulation. h Representative traces showing an increase of GABAAR-mediated tonic current in an interneuron after NG2 glia photoactivation (lower panel) from Pdgfrα-creERTM;ChR2-eYFP mouse compared with its basal tonic inhibition in an interneuron (upper panel) from Pdgfrα-creERTM;mGFP mouse. i Summary graph showing a significant enhancement of tonic GABA current in ChR2 compared with its mGFP control after blue light stimulation. Tonic GABA currents: 5.63 ± 1.59 pA, n = 10 cells in mGFP control vs. 16.38 ± 2.78 pA, n = 11 cells in ChR2, two-tailed unpaired t test, P = 0.004. j Representative images show post-immunostaining CCK-, NPY-, PV-, or SST- antibody with Alexa Fluor 568-loaded interneurons, which exhibited an enhanced frequency of mIPSCs after NG2 glia photoactivation. Scale bars, 20 μm. k The summary graph shows the proportion of each CCK+, NPY+, PV+, or SST+ interneurons from a total of 36 responsive interneurons recorded. Data are presented as mean values ± SEM and the error bar represents SEM.
