EFFECT OF P-CHLOROAMPHETAMINE ADMINISTRATION ON MONOAMINE METABOLISM IN THE RAT NUCLEUS-ACCUMBENS AND LOCOMOTOR-ACTIVITY - STUDIES WITH INTRACEREBRAL DIALYSIS IN FREELY MOVING RATS

Changes in the level of dopamine (DA) and its metabolites [3,4-dihydro xyphenylacetic acid (DOPAC) and homovanillic acid (HVA)] and serotonin (5-HT) and its metabolite [5-hydroxyindoleacetic acid (5-HIAA)] were determined sequentially in freely moving rats by using a brain dialysi s method. The purpose of the study was to find the relationship betwee n changes in the monoamine metabolism in the nucleus accumbens and loc omotor activities following PCA administration. Subsequently it was fo und that locomotor activity significantly increased 1 and 2 h after PC A administration (2 mg/kg, i.p.) while the DA content in the dialysis fluid rose significantly after 1 and 2 h. On the other hand, the 5-HT level did not show significant changes. The DOPAC, HVA, and 5-HIAA lev els were significantly reduced 1 to 6 h after PCA administration. It w as suggested that the increase in locomotor activity caused by PCA adm inistration is an expression of abnormal behavior caused by DA release from the nucleus accumbens.