[The freeze-etching and freeze-fracturing technics and their use for studying cellular membranes in the central nervous system].

In the present review, both subkinds of the method for membrane splitting, namely freeze-etching and freeze-fracturing techniques, are presented. After a brief historical survey, a mechanism of their action is described. Special attention is paid to the consecutive stages in applying these techniques--fixation, fracturing, etching, replication, cleaning and observation. A new idea for a better cleaning of the replicas and an explanation of the different occurrence of intramembranous particles on the membrane fracture faces are proposed. Finally, the application of the freeze-etching and freeze-fracturing techniques to visualize the intramembranous structure of membranes in the central nervous system is outlined.