[Fluorescence anisotropy and the structure of myelin. I. The theory of the method].

Theoretical aspects of the experiment dealing with measurements of fluorescence polarization degrees in stained myelinated nerve fibres are considered. Fluorescence polarization (FP) largely depends on the excitation azimuth, i.e. on the angle between the electrical vector of the polarized exciting light and the nerve fibre axis (geometrically it is a figure with the cylinder symmetry). The dependence of FP on the excitation azimuth is shown to be related to the degree of molecular orientation of dyes adsorbed on anisotropic layers of myelin membranes. This permits to associate FP with the structural changes of myelin membranes.