Lysophosphatidylcholine-induced incipient demyelination: involvement of a new tubular structure.

Demyelination was induced in the rat sciatic and tibial nerves by microinjection with lysophosphatidylcholine (LPC). Accompanying early myelin lysis (1-24 h) was the formation of vesicles and tubular structures. The tubules which are novel structures have a diameter range of 24-27 nm, a centre-to-centre spacing 30-50 nm and may extend for 3 microns in length. In this form they are arranged as a monolayer in the periaxonal space. As demyelination progressed and the periaxonal space widened the tubules increased in number and became more irregularly arranged. The tubules are apparently derived from the myelin lamellae/Schwann cell plasma membrane, while the axolemma remains intact.