Behavior, striatal and nucleus accumbens field potential patterns and dopamine levels in rats given amphetamine continuously.

Behavioral, electrophysiological (field potential recordings, analyzed by computer) and biochemical techniques were employed before, during and after 7 days of continuous administration of amphetamine to rats. Significant changes were observed using all three protocols. Behavioral alterations were greatest on the second day of treatment and progressively normalized during the remainder of treatment. Electrophysiological changes in the striatum were significant only on the second day of treatment, while electrophysiological alterations in the nucleus accumbens were significant on all treatment and recording days, and the magnitude of the changes paralleled the pattern of overt behavioral changes. Levels of DA in the striatum progressively decreased from normal throughout the treatment, declining to less than half of the control level by the sixth day of treatment. In contrast, DA levels in the nucleus accumbens were augmented on the second day of treatment and progressively approached the control level as treatment continued, again paralleling behavior and changes in the electrophysiology of the nucleus accumbens. These results indicate that continuous administration of amphetamine in rats differentially affects electrical activity in the striatum and nucleus accumbens as well as concentrations of DA. In addition, these results have implications for the study of paranoid schizophrenia.