Behavioral data are reviewed that give evidence for an indiscriminate involvement of brain catecholamines (CA), especially dopamine (DA), in nerve function, regardless of the time elapsed from their synthesis. Critical analysis of biochemical and pharmacological studies shows that a clear-cut distribution of brain catecholamines in two compartments ['newly synthesized' (NS) and 'main storage'] is not at all established, and moreover that there is no adequate proof that the difference in turnover rates attributed to these two supposed pools is due to a preferential extraneuronal release of NS-CA during nerve function rather than to a preferential (nonfunctional) intraneuronal deamination of NS-CA, or at least of NS-DA.