Reports

Dopamine: Stimulation-Induced Release from Central Neurons

Science  30 Apr 1971:
Vol. 172, Issue 3982, pp. 487-489
DOI: 10.1126/science.172.3982.487

Abstract

Dopamine, synthesized in rat brain slices from labeled L-tyrosine or L-dopa, can be released by electrical stimulation of a type known to induce neuronal depolarization. Pretreatment of the animals with 6-hydroxydopamine, which destroys central catecholamine-containing nerve terminals, substantially reduced the release of dopamine synthesized from [14C]tyrosine or from a low concentration of [3H]dopa, whereas the release of dopamine formed from a high concentration of [3H]dopa remained essentially unchanged. The observations that at high concentrations L-dopa may enter noncatecholaminergic cells, undergo decarboxylation to dopamine, and subsequently be liberated in response to depolarization suggest that dopamine may act as a substitute central transmitter, possibly in serotonergic neurons. This mechanism may contribute to L-dopa's clinical effects in parkinsonian patients.