Autoradiographic distribution study of 14C-DOPA in cat brain

The penetration and distribution in various areas of cat brain of 14C-DL-DOPA and/or its derivatives was studied by the autoradiographic technique. The highest activity was found, 1 hr after administration, in the caudate nucleus, putamen and n. accumbens, while hypothalamus, substantia nigra, substantia grisea pericentralis, tuberculum olfactorium, raphe nuclei and nucleus interpeduncolaris showed lower levels of labelling. Very low activity was detected in the cerebral cortex and in the other gray and white matter structures of brain. After pretreatment with a peripheral DOPA-decarboxylase inhibitor or high dosage of cold DOPA, the distribution pattern was not modified but the levels of radioactivity were greatly enhanced. The localization of the drug in dopaminergic structures and other areas of the brain is discussed.