Interactions of Taurine and Dopamine in the Striatum
The concentration of taurine in the striatum is high (23, 29). High-affinity taurine uptake has been demonstrated in striatal synaptosomes (5, 24), and selective uptake into a subpopulation of striatal neurons (4). Both the content and K+ -stimulated release of taurine are reduced after an intrastriatal injection of kainate, indicating a neuronal localization of the amino acid (25, 31). Although electrophysiological data on taurine in the striatum are scant, the above evidence suggests that taurine is involved in striatal functions. The striatum is particularly rich in dopaminergic neurons, rendering it possible that taurine could modulate dopaminergic transmission. Indeed, intraventricularly injected taurine increases the synthesis of dopamine in the rat brain and inhibits the firing of dopamine neurons (7). Intraventricular taurine also stimulates prolactin secretion, possibly via interaction with dopamine or serotonin transmitter systems (34), and unilateral intranigral injection of taurine induces a dose-dependent contralateral circling behavior which is partially blocked by haloperidol (12). I have now further elucidated the modulatory role of taurine in the function of striatal dopaminergic systems by studying mutual interactions of taurine and dopamine in release and uptake processes in the rat striatum. The effects of taurine on the binding of tritiated spiperone, a ligand for dopamine receptors, to striatal synaptic membranes was also investigated.
KeywordsDopamine Release Striatal Slice Taurine Release Taurine Uptake Striatal Membrane
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