[Fluorescence histochemical and neurohistological investigations on the nucleus raphes dorsalis of the rat (author's transl)].

The nucleus raphes dorsalis of the adult rat was investigated by means of fluorescence histochemical and neurohistological methods. After application of Falck-Hillarp-technique characteristics 5-HT-fluorescence could be seen in many, albeit not all of the cells of this nucleus. After using the rapid Golgi impregnation technique, 3 neuron types could be demonstrated: type-1-neurons (polygonal neurons with somatic spines); type-2-neurons (fusiform neurons), and type-3-neurons (pyriform neurons). The type-1- and type-2-neurons are, due to their different axon projection mode, considered to be efferent raphe neurons. The type-3-neurons are thought to be raphe interneurons. The type-1-neurons are inferred to represent the 5-HT producing neurons of the nucleus raphe dorsalis.