Figure 1. Isoflurane reduces dendritic spine density and alters spine morphology.

Hippocampal neuron cultures transfected with eGFP as a cell volume indicator were exposed to 95% air/5% CO₂ (Ctl) or 2 vol% isoflurane in 95% air/5% CO₂ for 60 min at 37°C. A-representative full image showing the dendritic arbor of a control neuron and of a neuron treated with isoflurane for 60 min; B-representative images of single ROIs at various times of exposure to isoflurane. Spine number was counted manually at the indicated time points. Isoflurane significantly reduced spine density (C) by one-way ANOVA with Dunnett's post hoc test (**p<0.01; ***p<0.001; ****p<0.0001). Exposure to isoflurane reduced mean spine length (D-left panel) with no significant change in spine width (D-right panel) by one-way ANOVA with Holm-Sidak post hoc test (****p<0.0001). Data are mean ± SEM; n = 30 to 40 dendritic ROIs per experimental group; n = 600 to 1260 dendritic spines for spine density, spine length and spine head width per experimental group. Scale bar in 1A = 10 µm, in 1B = 5 µm.