Figure 4. Fluoxetine prevents Ca²⁺ overload of NMJs in mSCS.

Left. Serial TA muscle sections labeled for cholinesterase (dark brown) to localize endplates and GBHA (red) to localize Ca²⁺ overloading in WT and mSCS. Ca²⁺ overloading was found at endplates of mSCS, but not in wild type (WT). Scale bar=60µm. Middle. Quantitation of Ca²⁺-overload of endplates (% GBHA-labeled endplates) in WT and in untreated mSCS mice (εL269F) and) with treatment of serial concentrations of fluoxetine. Endplates from WT TA showed no Ca²⁺-labeled endplates, while a significant number of NMJ were overloaded with Ca²⁺ in untreated εL269F (37.3±5.7%) and control εL269F treated with saline (mSCS (εL269F)-saline; 38.2±2.6%) whereas Ca²⁺-overloaded endplates were significantly decreased in 7.2 µg/g (15.8±2.3%) and 9.6 µg/g (11.9±4.2%) treatment. Right. The similar results were also shown in mSCS mice (δS268F). Compared with δS268F (44.7±0.5%) and control δS268F (44.3±2.7%), treated δS268F with a dose of 7.2 and 9.6 µg/g reduced Ca²⁺-labeled endplates to 17.4±0.8% and 6.1±1.7%, respectively. n=5–7; ***p<0.001. All comparisons were analyzed by Student’s t-test.