Figure 1.

Long-term fluoxetine treatment induces morphological changes in proximal dendritic spines of CA1 pyramidal neurons. (A) Left: A representative image of a Golgi stained neuron from a fluoxetine-treated rat. CA1 stratum radiatum (s.r.) subfield was chosen for analysis. Scale bar: 50 μm. Right: representative dendritic segments of saline and fluoxetine-treated rats under larger amplification. Scale bar: 10 μm. (B) The selected dendritic segments in (A) (right panels) are shown with identified spine types: filopodia/thin (T), stubby (S), and mushroom/branched (M). The asterisks indicate two superimposed M-type spines that were resolved by observation at different focal planes. Bar graphs show spine density and the abundance of spines in each of the three shape categories. Results are presented as mean ± SEM and were determined from 11 cells per condition, obtained from eight saline (total spines, 874)- and nine fluoxetine (total spines, 957)-treated rats. Data were statistically evaluated with the Mann–Whitney U-test, ^*p < 0.05, ^**p < 0.01, ^***p < 0.001.