An improved method for perfusion fixation of neural tissues for electron microscopy.

A method employing vascular perfusion for improved preservation of biological ultrastructure is described, and its effectiveness demonstrated for mammalian nervous tissues. Following a physiological saline flush into the aorta, hydrogen peroxide and glutaraldehyde in phosphate buffer are perfused. After buffer rinses, tissue blocks are postfixed in osmic acid and potassium ferrocyanide. The success rate is enhanced greatly by close attention to details of perfusion technique. Advantages of the method include more uniform and complete preservation. In particular, superior images of membranous elements, glycogen granules and basal laminar material are achieved. Adjustments in osmolality may render the procedure suitable for nonmammalian forms and other tissues.