A method for simultaneously revealing both the cytoskeleton and membranous cell organelles for scanning electron microscopy, and its application to rat tissues.

Perfusion with a dilute saponin solution before perfusion and immersion fixation with 0.5% glutaraldehyde and 0.5% formaldehyde, followed by routine processing for high-resolution scanning electron microscopy, allows a variety of cytoskeletal elements to be well preserved. Membranous organelles are also clearly seen, allowing the three-dimensional relationships of membranes and filaments within the cell to be directly observed. In particular, in the rat intermediate filaments were seen to terminate on smooth endoplasmic reticulum and nuclear envelopes of intestinal epithelia, and to form networks between mitochondria and rough endoplasmic reticulum in podocytes of renal glomeruli.