Figure 1.

Sorafenib induces morphological alterations and reduces the synaptic vesicle pools in neurons. (a) Representative recordings of neurons treated with 10 μM sorafenib (lower row) or controls (upper row) for 24 h. The samples were transfected with an EGFP-synaptobrevin2 (synaptopHIuorin) construct to visualize vesicles, stained against β3-tubulin to visualize the neurites and stained with Hoechst33342 that stains the nuclei. The scale bars span 50 μm. (b) After a 24 h 10 μM sorafenib treatment (or control), the readily releasable synaptic vesicle pool (RRP) size (released upon electrical stimulation with 40 stimuli at 20 Hz) was measured relative to the total vesicle population (perfusion with 50 mM ammonium chloride) for each synapse. The bar plot shows means with standard errors of the mean. Number of experiments: n=32 for control, n=7 for 10 μM sorafenib; unpaired two-sided t-test, P=0.2013. (c) After a 24 h 10 μM sorafenib treatment (or control), the synaptic vesicle recycling pool (RP) size (released upon electrical stimulation with 1200 stimuli at 40 Hz) was measured relative to the total vesicle population (perfusion with 50 mM ammonium chloride) for each synapse. The bar plot shows means with standard errors of the mean. Numbers of experiments: n=32 for control, n=7 for 10 μM sorafenib; unpaired two-sided t-test, ****P=0.0002.