Long-range intercellular signalling in glial cells of the peripheral nerve.

Schwann cells are considered to be electrically silent satellite cells surrounding axons, although they exhibit ionic channels, some of which are similar to those employed by axons for the generation and transmission of nerve impulses. Here, we show that Schwann cells generate, in response to a short and gentle electrical stimulus, a long-lasting depolarizing potential, slowly propagating along the Schwann cell synsitium. This electrical signal, which in situ might be generated by the Schwann cells in response to the axonal electrical activity, constitutes in the peripheral glia a novel form of long-range intercellular signalling, which may be involved in the regulation and modulation of the axonal excitability.