Figure 5
Lithium stimulates nAChR turnover and density in denervated NMJs. (A) Experimental design used to analyse the effect of lithium on nAChRs turnover in denervated NMJs. Since one day before facial nerve cut, lithium or sodium chloride were subcutaneously injected on top of the LAL muscle daily until BTX2 labelling. The initial surface nAChR pool was labelled 3 days after facial nerve cut (BTX1) while newly incorporated nAChRs (BTX2) were stained 7 days after nerve cut. (B) Pictures show representative confocal images of merged BTX1 and BTX2 staining in denervated and contralateral LAL muscles from sodium or lithium-treated animals. Bar = 20 µm. (C–E) nAChRs turnover was determined by quantifying the BTX2/BTX1 fluorescence intensity ratio. BTX1 (F) and BTX2 (G) fluorescence intensities are shown to determine the contribution of each nAChR pool in all tested conditions. (H) Total fluorescence signal of BTX1 plus BTX2 in entire endplates was also quantified. Graphs represent mean values ± SD along with individual data for sodium or lithium condition. For statistical analyses, a t-test was employed for comparison between controls and lithium-treated groups from 30 to 40 NMJs per animal (N = 3 animals per group). ****p < 0.0001; ***p < 0.001; **p < 0.01.
