Fig. 5.

Ultrastructural morphology of synapses formed at low levels of agrin expression. The two major types of morphologically distinct synapses present in the P3–P5 rat hippocampal cultures are shown in untreated (C) and in sense (S)- and antisense (AS)-treated neurons.Top row, Type I synapses with distinct postsynaptic densities. Bottom row, Type II synapses (presumably inhibitory) without postsynaptic densities. No noticeable changes in morphology were observed between untreated and treated neurons. The frequency of type I and II synapses was similar in all experimental conditions (∼85 and 15%, respectively).