Identification of neurons of origin providing the dopaminergic innervation of the hippocampus.

It was proved if there is an innervation of the hippocampus by dopaminergic neurons of the ventral tegmental area. Methods of labeling neurons by intrahippocampal injections of retrograde tracers were combined with fluorescence histochemical investigations of the same cells. An innervation of the hippocampus by the dopaminergic cell groups "A-9" and "A-10" could not be verified whereas, in the sphere of the raphe nuclei besides serotoninergic cells retrogradely labeled neurons were found exhibiting a dopamine like aminergic fluorescence.