The Role of Brain Dopamine in Behavioral Regulation and the Actions of Psychotropic Drugs

By comparing biochemical and behavioral actions of d- and l- isomers of amphetamine, the authors show that locomotor hyperactivity, an animal model for the central stimulant effects of amphetamine, is mediated by brain norepinephrine. By contrast, stereotyped, compulsive gnawing behavior in rats, which resembles symptoms of amphetamine psychosis, appears to be regulated by brain dopamine. Since haloperidol, a potent blocker of dopamine receptors, is uniquely efficacious in treating Gilles de la Tourette's disease, the authors suggest that hyperactivity of dopamine systems in the brain may be a factor in the pathophysiology of this condition.