The Schwann cell: a reappraisal of its role in the peripheral nervous system.

The Schwann cell is clearly essential for the maintenance of axonal integrity--yet we know little of the regulatory mechanisms governing its behaviour at any point in its life cycle, or of the nature of its interaction with the axons with which each Schwann cell is associated. In this article, the involvement of the Schwann cell in myelinogenesis, aspects of Schwann cell-axon recognition, the experimentally-demonstrable 'bipotentiality' of the Schwann cell and the possible functional significance of the proliferative response of the Schwann cell that occurs after injury are discussed. The isolation and preparation of pure populations of Schwann cells which can be injected or implanted into a damaged nerve, coupled possibly with the localized application of drugs to manipulate the cellular responses to injury within the nerve, represent interesting areas of recent research which may be applied in planning methods of therapeutic intervention in the treatment of peripheral nerve injury.