Rat brain sections were treated with fine granular cationic iron colloid, which was prepared by boilling ferric chloride with hydrazine hydrate and cacodylic acid (Murakami et al., 1986). The sections were then treated with ferrocyanide and HCl for Prussian blue reaction or with protein silver and gold chloride for physical development. Physical development had an advantage over Prussian blue reaction in that it produces clear and highly contrasted images under a light microscope. Thus, the perineuronal sulfated proteoglycans and the fine processes of the nerve cells were clearly demonstrated by physical development.
Cationic iron colloid
physical development
Prussian blue reaction
protein silver
gold chloride
Bodian's silver impregnation