The relationship between phencyclidine-induced stereotyped behavior and dopamine release using in vivo voltammetry

The present study was designed to examine the effect of phencyclidine (PCP) on the dopaminergic neuronal function in the striatum by using in vivo electrochemical technique. Haloperidol (HAL) at the dose increases 3,4-dihydroxyphenylacetic acid (DOPAC) level produced an obvious increase of electrochemical signal in the rat striatum at +250 mV, and apomorphine (APO) reversed the effect of HAL. Methamphetamine and methylphenidate increased the electrochemical signal at the dose increases DOPAC level. Tryptophan produced no change in the electrochemical signal at the dose increases serotonin and its metabolite levels. These results suggest that changes in the striatal electrochemical signal at +250 mV reflected the oxidation of extracellular DA or DOPAC, but not serotonin or its metabolite. Moreover, changes in the electrochemical signal at +250 mV were correlated with the DA related behaviors. PCP (7.5 mg/kg, i.p.) increased in the electrochemical signal in parallel with appearance of the stereotyped behaviors including headweaving, backpedalling and turning which were antagonised by neuroleptics, and it produced a marked increase in DOPAC level in the striatum. These results show that the PCP acts as a DA releaser, and make it clear the relationship between PCP-induced stereotyped behaviors and DA release in the striatum by using in vivo differential pulse voltammetry in conscious animals.