Postsynaptic density visualized by whole mount electron microscopy.

Detergent-unextractable structures of synaptic plasma membrane of rat cerebrum were observed by whole mount electron microscopy. The globular structures were identified as postsynaptic densities (PSDs) from several criteria and appeared to consist of folded strings, to which a number of other molecules might be attached. Some of the globular structures were attached with subsynaptic webs. The structures contained a number of finely striated small strips (10-20 nm wide, 60-100 nm long), parts of which were peeled off from PSD cytoskeletal base by N-lauroyl sarcosinate.