Membrane specialisations between demyelinated axons and astroglia in chronic EAE lesions and multiple sclerosis plaques

Abstract

AXOLEMMAL specialisations are known to exist along myelinated fibres in the adult vertebrate central nervous system (CNS), particularly at nodes, between the axon and the oligodendrocyte, and at presynaptic sites¹. However, modified regions of axonal membrane have not been described in relation to astroglial cells. In demyelinated lesions in the CNS, it has always been assumed that the naked segment of an axon, although intimately invested by glial scar tissue, shares no junctional relationships with its scarring environment. This report documents for the first time membrane specialisations between naked CNS axons and fibrous astroglial cell processes, developing subsequent to demyelination. These structures may have physiological implications.