On the association between perinodal astrocytic processes and the node of Ranvier in the C.N.S.

Abstract

Associations between the axolemma of nodes of Ranvier in the C.N.S. and perinodal astrocytic processes have been confirmed in the guinea pig spinal cord. Since perinodal astrocytic processes were found to be a consistent feature at such nodes, it is proposed that they represent the C.N.S. analogue of the Schwann cell fingers at P.N.S. nodes. Although they assumed a variety of configurations, perinodal astrocytic processes rarely approached the complexity and regularity of Schwann cell profiles at PNS nodes. The findings are discussed in terms of the relevance between perinodal astrocytes and the maintenance of an electrogenic pump at the node.