| Abstract: | N.n. tibialis were investigated in 5--10-day-old rats, using electron microscopy. All the main types of membrane junctions were found in the area of forming nodose: hemi-desmosomal, serial desmosomal, continuous, septate, gap and tight junctions. The junctions were both of glio-glial and axon-glial type. These types may be stages of a unified process of membrane interaction. They are located in multiple loci and form intermediate dense myelin line upon merging. Such junctions result form aggregation and retraction of outer para-membrane electron dense material. The same mechanism of inner surface membrane coupling was observed in lamellipodia of lemmocytes. Thus "inside out" local junctions were formed. Merging of these junctions forms the main dense line of myelin. Consequently, compact myelin, tHus formed, should be considered as a gigantic complex membrane junction. |
