Drug interactions with brain biogenic amines and the effects of amphetamine isomers on locomotor activity

Administration of single IP doses of 1.0 or 4.0 mg/kg of d-amphetamine evoked an increase in mouse spontaneous motor activity (SMA); in contrast, 1.0 mg/kg of l-amphetamine had no significant effect, while 4.0 mg/kg caused a decreased SMA. Pretreatment with aMT or pargyline had little effect on the actions of the l-isomer, but reduced the magnitude and duration of the stimulatory effect of d-amphetamine. Pretreatment with p-chlorophenylalanine had little effect on the actions of d-amphetamine but completely abolished the depressant actions of the l-isomer. Reserpine pretreatment markedly reduced basal SMA levels; such pretreatment caused both d- and l-amphetamine to act as stimulants of SMA.