Comparison of the effects of the novel antipsychotic agent remoxipride on dopamine and noradrenaline turnover in the rat brain.

The ex vivo effects of the antipsychotic dopamine receptor antagonist remoxipride on dopamine and noradrenaline turnover in the rat brain have been compared. Remoxipride (5-125 mumol/kg intraperitoneally) produced large increases in striatal DOPAC and HVA concentrations with only maginal effects on striatal, hippocampal and hypothalamic MHPG concentrations. Both remoxipride (5.6 mumol/kg intraperitoneally) and haloperidol (0.23 mumol/kg intraperitoneally) increased the rate of striatal dopamine disappearance following inhibition of tyrosine hydroxylase by H 44/68 without corresponding effect on hypothalamic and frontal cortical noradrenaline disappearance. It is concluded that at doses of remoxipride producing compensatory increases in dopamine turnover, there is little or no effect on noradrenaline turnover, confirming the in vitro dopamine:noradrenaline selectivity of this compound.