[Structural changes in the myelin sheath membranes exposed to anisotonic media. A fluorescence polarization study]

Extrinsic fluorescence polarization (P parallel and P perpendicular) of intact myelinated nerve fibres in anisotonic media has been investigated. Fluorescent probes of Acridine orange and Perylen were used for the experiment. Changes in fluorescent polarization of nerve fibres, associated with osmotic movement of water, arise immediately after the incubation of fibres in hypo- or hypertonic solutions. During exosmotic and endosmotic movement of water P parallel and P perpendicular and in quite a different manner. This fact demonstrates an asymmetry of structural membrane alterations. The results obtained are explained by asymmetry of swelling and shrinking of carbohydrate gel between two adjacent extracellular membrane surfaces of the myelin sheath.