Figure 5.

Ultrastructural synaptic alterations in primary neurons treated with LDN. A–H, Representative electron micrographs of cultured neurons treated with vehicle or 10 μm LDN for 24 h. A–D, Control, untreated neurons exhibit normal characteristics for presynaptic terminals (pst), postsynaptic densities (psd), mitochondria (m), and dendritic processes (dp). E–H, LDN-treated neurons display abnormal synaptic structures demonstrated by enlarged presynaptic terminals, irregular postsynaptic densities, abundant coated pits (cp) and clear synaptic vesicles (sv), and vacuolization of dendrites. Magnification, 30,000×. Quantifications of PSD diameter (I), number of vesicles (J), and synaptic zone contact (K) in control and LDN-treated neurons are shown. Averaged results from a total of 10 micrographs for each grid (9 grids per condition) were used for data analysis. Mean values ± SEM are shown. *p < 0.01, unpaired Student's t test.