The structure of synaptosomal plasma membrane.

Synaptosomal plasma membrane (SPM), like other plasma membranes, is composed of lipids and proteins and appears to conform to the "fluid mosaic" model proposed by Singer and Nicolson. SPM components show a marked asymmetry with respect to their inside-outside distribution, with the majority of proteins being external. The lateral distribution of proteins is also somewhat asymmetric; this asymmetry is maintained by the immobilization of species at the junction.