ABSTRACT
V. LEVEL* CNRS, Physiologie Integrative Cellulaire et Moleculaire, UMR 5123, Bat Rene Dubois, 8 rue Dubois, Campus La Doua, 43 Boulevard du 11 novembre, 69622 Villeurbanne, France
Abstract-In response to the depolarization of the neuronal membrane, dopamine is released into synapses and binds to postsynaptic specific receptors. It is likely that some molecules can also diffuse out of the synapse, and reach distant targets. Alongside this process, active transport also occurs, outside the synapses, and involving a carrier protein able to act bi-directionally. These two releasing processes are concerned with the intraterminal pools of dopamine located or not in vesicles. From this complexity of storing and releasing mechanisms, it emerges that regulation of dopamine release involves the intraterminal amine metabolism. Indeed, various pharmacological treatments and physiological situations seem to modulate basal or evoked processes of release by alterations of dopamine synthesis, storage or catabolism before the action of the natural triggers, the ion gradients. Pathological situations, including the Parkinson's syndrome for instance, could result from such tonic modifications of dopamine metabolism in the terminals. In the present review, the variety of dopamine releasing agents or experimental situations is considered for their involvement in the amine metabolism.
