Extended Data Fig. 3: Increased contacts between microglia and neuronal somata or dendrites in response to general anesthesia.
From: Microglia enhance post-anesthesia neuronal activity by shielding inhibitory synapses
a, Two-photon imaging of microglia (Cx3cr1GFP/+, green) and neurons co-labelled with GCaMP6s (green) and tdTomato (red). Representative time series images of interaction between microglial bulbous endings (green) and neuronal soma (red) during anesthesia. White arrowheads indicate contact sites. Scale bar: 10 μm. b, Graph shows that number of microglia-neuronal soma contact sites before (Awake), during (Isoflurane) and after anesthesia (Emergence) was significantly increased during anesthesia (Awake versus Isoflurane, p = 0.0030; Awake versus Emergence, p = 0.0199; Isoflurane versus Recovery, p = 0.0640). Solid lines represent the mean ± SEM from n = 5 imaging field from 5 mice. c, Duration of microglial interaction (Awake versus Isoflurane, p = 0.0020; Awake versus Emergence, p = 0.0079; Isoflurane versus Recovery, p = 0.7197). n = 5 imaging field from 5 mice. d, Representative time series images of interaction between microglial bulbous endings (green) and neuronal dendrites (red) before, during, and after anesthesia. Microglia-neuronal dendrite interaction was increased during anesthesia (indicated by white arrowheads). Scale bar: 5 μm. e, Graph shows number of microglia-neuronal dendrite contact sites per 100 μm length of dendrite (Awake versus Isoflurane, p = 0.0016; Awake versus Emergence, p = 0.9572; Isoflurane versus Recovery, p = 0.0041). Solid lines represent the mean ± SEM from n = 6 imaging fields from 3 mice. f, Graph shows duration of observed microglia-dendrite interactions before, during, and after anesthesia (Awake versus Isoflurane, p = 0.2029; Awake versus Emergence, p = 0.0174; Isoflurane versus Recovery, p = 0.3960). n = 6 imaging fields from 3 mice. g, Representative velocity changes in microglial bulbous ending in contact with neurons. h-i, Time-course of velocity changes in microglial bulbous endings (h) and normal processes (i, excluding bulbous endings) during awake, anesthesia, and emergence (bulbous endings: Awake versus Isoflurane, p = 0.8423, Awake versus Emergence 15 min, p = 0.7476; Awake versus Emergence 30 min, p = 0.5805; Awake versus Emergence 45 min, p = 0.1302; Awake versus Emergence 60 min, p = 0.0237. normal processes: Awake versus Isoflurane, p = 0.0447; Awake versus Emergence 15 min, p = 0.9919; Awake versus Emergence 30 min, p = 0.8353; Awake versus Emergence 45 min, p = 0.5313; Awake versus Emergence 60 min, p = 0.2188). Dashed lines indicate data from an individual animal while solid lines, columns and error bars show the mean ± SEM from n = 4 mice. One-way ANOVA followed by Tukey (b, c, e, f) and Sidak (h, i) post-hoc test; n.s., not significant; *p < 0.05 and **p < 0.01.
