LIGHT-MICROSCOPIC VISUALIZATION OF MONOAMINE-OXIDASE USING A CERIUM METHOD

H2O2-generating monoamine oxidase can be visualized in the light micro scope with tetrazolium, metal salt (ferricyanide) and coupled peroxida tic oxidation methods. Due to methodological draw-backs these procedur es do no allow satisfactory results. In search for an alternative meth od a light microscopic cerium procedure was designed in which the prim ary reaction product, cerium perhydroxide, serves for the generation o f amplified and intensified diaminobenzidine brown. With this cerium-d iaminobenzidine-H2O2-Co method monoamine oxidase was visualized more e asily and reliably and with higher sensitivity and more precise locali zation than with the other techniques. At present this method is consi dered to be the procedure of choice and was used to re-investigate and investigate the distribution of monoamine oxidase in rats, mice, gerb ils, guinea-pigs, marmosets, monkeys and man. In these species many ce lls and tissues showed monoamine oxidase activity where the enzyme has not yet been found before and the structures with already known monoa mine oxidase activity showed an improved localization.