It is likely that, in human individuals, the Probenecid technique supplies information on the turnover of 5-hydroxytryptamine (5-HT) and dopamine (DA) in the central nervous system. The data obtained by this technique in this study suggest a diminished central 5-HT and DA turnover in patients suffering from depressions. The changes in 5-HT metabolism were most marked in bipolar depressions with the features of the endogenous depressive syndrome; changes in DA metabolism were most marked in depressions with marked motor retardation.
These findings lend support to the hypotheses which postulate a correlation between deficient central monoamine metabolism and the occurrence of depressive symptoms. Moreover, they justify the hypothesis that depressive syndromes similar in terms of psychopathological symptoms may nevertheless be based on disparate metabolic substrates. Such a situation would have important implications for the pharmacotherapy of depressive syndromes.
van Praag HM, Korf J. Cerebral Monoamines and DepressionAn Investigation With the Probenecid Technique. Arch Gen Psychiatry. 1973;28(6):827-831. doi:10.1001/archpsyc.1973.01750360053007