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 α-methyltyrosine or the dopamine precursor l-3,4-dihydroxyphenylalanine on radioligand binding to the dopamine transporter in homogenates of rat striatum and nucleus accumbens were assessed. Chronic α-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 α-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.