EFFECT OF HALOPERIDOL ON THE BEHAVIORAL STIMULATION BY N-CYANOMETHYLMETHAMPHETAMINE, A MAIN PRODUCT OF SMOKING METHAMPHETAMINE MIXED WITH TOBACCO

N-Cyanomethylmethamphetamine is a main product of smoking methamphetam ine mixed with tobacco. The aim of this experiment was to evaluate the effects of haloperidol on behavioral stimulation by N-cyanomethylmeth amphetamine (3 mg/kg s.c.) in terms of ambulation in mice. Repeated ad ministration of N-cyanomethylmethamphetamine, carried out 5 X at 3-day intervals, induced a sensitization to its ambulation-increasing effec t. Haloperidol (0.01, 0.03, 0.1 and 0.3 mg/l<g s.c.) significantly inh ibited not only the acute stimulant effect of N-cyanomethylmethampheta mine but also the induction of sensitization. The dose-effect curves f or the inhibitory effects of haloperidol on the N-cyanomethylmethamphe tamine-induced ambulatory stimulation were almost the same between the drug-naive and N-cyanomethylmethamphetamine-sensitized mice. Moreover , such behavioral characteristics of N-cyanomethylmethamphetamine; the behavioral stimulant effect, the induction of sensitization following repeated administration, and the inhibition of its effects by haloper idol, were qualitatively the same as those of methamphetamine (2 mg/kg s.c.). These results suggest that N-cyanomethylmethamphetamine posses ses methamphetamine-like central stimulant effect and that D-2 dopamin ergic mechanisms are involved in the effect of N-cyanomethylmethamphet amine.