Amphetamine: Differentiation by d and l Isomers of Behavior Involving Brain Norepinephrine or Dopamine

Abstract

d-Amphetamine is markedly more potent an inhibitor of catecholamine uptake by norepinephrine neurons in the brain than is l-amphetamine, whereas the two isomers are equally active in inhibiting catecholamine uptake by the dopamine neurons of the corpus striatum. In behavioral studies,d-amphetamine is ten times as potent as l-amphetamine in enhancing locomotor activity, while it is only twice as potent in eliciting a compulsive gnawing syndrome. This suggests that the locomotor stimulation induced by amphetamine involves central norepinephrine, while dopamine neurons play an important role in the induced compulsive gnawing behavior. Assessment of differential actions of d- and l-amphetamine may be an efficient method to differentiate behaviors involving norepinephrine or dopamine in the brain.