Repeated exposure to the herbicide atrazine alters locomotor activity and the nigrostriatal dopaminergic system of the albino rat

► ATR injections decreased locomotor activity after every administration. ► ATR induced a short-lasting hypoactivity that disappeared 10 days later. ► Persisting changes on the DAergic system were revealed with an amphetamine challenge. ► ATR induced a short-lasting decrease in striatal monoamine levels. ► ATR induced a down-regulation of mRNA for Th and DAT and increased VMAT2 mRNA expression.