DOPAMINE TRANSPORTER BINDING IN RAT STRIATUM AND NUCLEUS-ACCUMBENS ISUNALTERED FOLLOWING CHRONIC CHANGES IN DOPAMINE LEVELS

The effects of chronic treatment with the tyrosine hydroxylase inhibit or a-methyltyrosine or the dopamine precursor L-3,4-dihydrox yphenylal anine on radioligand binding to the dopamine transporter in homogenate s of rat striatum and nucleus accumbens were assessed. Chronic alpha-m ethyltyrosine administration decreased dopamine levels in both the str iatum and nucleus accumbens without a resulting change in [H-3]mazindo l binding to the dopamine transporter in either brain region. In a sec ond experiment, chronic administration of a-methyltyrosine or L-3,4-di hydroxyphenylalanine produced significant decreases and increases, res pectively, in striatal dopamine levels without altering the binding of [H-3]WIN-35,428, a chemically distinct dopamine transporter radioliga nd. These data suggest that even dramatic fluctuations in brain dopami ne levels do not modulate the abundance of the dopamine transporter.