Diaminobenzidine oxidation in cerebellar histological sections

Cerebellar histological sections were incubated in media containing 3,3'-diaminobenzidine (DAB). Microscopic observation showed the presence of oxidated DAB in all cerebellar cells. Said oxidation of DAB in the cerebellar structures was produced in the absence, as well as in the presence, of exogenous H2O2 in the incubation medium. The erythrocytes existent in the blood vessels were capable of oxidating more intensely the DAB when H2O2 was present in the incubation medium. When the sections were pretreated and incubated with CNK, sodium azide and perodic acid, the oxidation of DAB was not produced. The observation with electron microscope showed that the DAB oxidation is produced in mitochondria, coated vesicles, and lysosomes. The possible mechanisms intervening in the oxidation of DAB in cerebellar structures are discussed.