Comparative Morphology of NMJ and Spine Synapses

by Josef Spacek

dendritic-spine-ultrastructure

Fig. 1: Examples of dendritic spine ultrastructure showing dense plates. A dendritic spine (left) may contain a spine apparatus with inner dense plates and outer dense plate radiating into the postsynaptic density (arrow). Other examples of outer dense plates (arrows) are also seen in the heads of other spines (middle,left). Scale = 0.2 µm. (From Spacek, 1985, with courtesy of Springer-Verlag ).

Fig. 2: Basic shape of dendritic spine (left) compared to that of the neuromuscular junction (right). The dendritic spine attaches to the dendrite with a narrow neck and receives a synapse on a bulb-like head. This lollipop shape is similar to the shape of the interfolds sectioned transversely. Opened axon terminal in green, synaptic vesicles in purple.

dendritic-spine-comparison

Fig. 3: Comparison of dendritic spine (left) and motor end plate interfold (right) with their dense plate and strip (arrows). (From Couteaux and Spacek, 1988, with courtesy of Springer-Verlag.)