Differential effects of primary fixation with glutaraldehyde and osmium upon the membranous systems of the strial and external sulcus cells.

Ultrastructural preservation of the lateral cochlear wall differs between primary osmium fixation and primary glutaraldehyde fixation. Of significance in this study was the fact that whereas glutaraldehyde fixation preserves the parallel plasma membranes of interdigitations of the strial and external sulcus cells, fixation with osmium occasionally produces a breakdown of selected areas of membranes into apparent vesicles. The occurrence of these membrane artifacts was more common within the external sulcus cells. Reasons for the differential effects of the fixatives may include their differing modes of action. Care should be taken when evaluating unusual ultrastructure, since the type of fixative employed may be causal.