Polarization microscopic evidence for an oriented cytoplasmic structure in the "dark" variants of adrenalin-storing cells.

A diffuse cytoplasmic birefringence confined to "dark" adrenalinstoring cells has been described. The main optical characteristics of the birefringence factor include: regular orientation of birefringence relative to the base-apex axis of cells; additive anisotropic staining with methods based on the principle of topo-optical staining reactions; dependence of birefringence on labile morphologic properties. On the basis of the capacity of the macromolecular matrix of chromaffin granules to form lamellar liposomal structures in vitro it has been proposed that a reorientation of molecular organization in the matrix of chromaffin cells is responsible for the observed optical phenomenon. The direction of birefringence was explained by a preferential direction of contractile forces acting during "dark" cell formation.