Stimulus properties of d-amphetamine as compared to l-amphetamine.

Rats were trained to discriminate between d-amphetamine and saline. The discriminable ED50 values for amphetamine isomers were calculated from dose--response curves and the potency ration was 4.9 Co-administration of the ED50s was shown to produce synergistic effects suggesting that the amphetamine isomers may share a common site of action.