Selective uptake of 3H-6-hydroxydopamine by neurones of the central nervous system

Summary Tritiated 6-hydroxydopamine (6-OHDA) was injected into the lateral ventricle of rats and rabbits and visualized by means of autoradiography. In unfixed frozen sections, radioactive material was found penetrating about 2 mm into the periventricular tissue within 4–48 hours after injection. Radioactivity was localized preferably in particular nuclei, leaving the fiber bundles nearly free of label.In formalin-fixed paraplast-embedded sections the appearance of silver grain clusters was the very characteristic finding representing most probably uptake into presynaptic terminals. Labelling pattern suggests highly selective uptake of 6-OHDA by terminals of noradrenaline and dopamine-containing neurones; also a few single neurones of particular mesencephalic nuclei showed uptake by their nerve cell soma. A specific uptake mechanism for 6-OHDA which is most likely identical with the monoamine pump may explain the well-known selectivity of the pharmacological action of 6-OHDA.Mapping of silver grain clusters and an analysis of the frequency by which they occur in different areas of the brain were performed.