Dopamine transporter binding in rat striatum and nucleus accumbens is unaltered following chronic changes in dopamine levels.

The effects of chronic treatment with the tyrosine hydroxylase inhibitor alpha-methyltyrosine or the dopamine precursor 1-3,4-dihydroxyphenylalanine on radioligand binding to the dopamine transporter in homogenates of rat striatum and nucleus accumbens were assessed. Chronic alpha-methyltyrosine administration decreased dopamine levels in both the striatum and nucleus accumbens without a resulting change in [3H]mazindol binding to the dopamine transporter in either brain region. In a second experiment, chronic administration of alpha-methyltyrosine or L-3,4-dihydroxyphenylalanine produced significant decreases and increases, respectively, in striatal dopamine levels without altering the binding of [3H]WIN 35,428, a chemically distinct dopamine transporter radioligand. These data suggest that even dramatic fluctuations in brain dopamine levels do not modulate the abundance of the dopamine transporter.