[The activities of the transmitter metabolizing enzymes monoamineoxidase and acetylcholinesterase and of succinic dehydrogenase were investigated in the telencephalon of Salmo irideus (teleostei) (author's transl)].

The activities of the transmitter metabolizing enzymes monoamineoxidase and acetylcholinesterase and of succinic dehydrogenase were investigated in the telencephalon of Salmo irideus (teleostei). There is a high reaction intensity of the MAO in the whole telencephalon with graded differences between the various nuclear areas. It is highest in the area dorsalis telencephali; the larger fiber tracts (Tr. olfactorius medialis et lateralis; medial and lateral forebrain bundle) are strong MAO-positive, too. There is an extremely weak AchE-reaction throughout the telencephalon. The only nuclear area which is clearly histochemically demonstrable is the regio Dm2 in the area dorsalis telencephali. The SDH-activity is demonstrable in the whole telencephalon. The activity is higher in the area dorsalis as compared with the area ventralis telencephali. In the ependym there are only a few traces of MAO- and SDH-reaction products. The recent findings may support, from a histochemical view, the hypothesis that the telencephalon of Salmo irideus represents brain structures which show structural and functional similarities with limbic telencephalic structures of higher vertebrates.