Neural basis of psychomotor stimulant and opiate reward: Evidence suggesting the involvement of a common dopaminergic system

Data are reviewed that suggest a common neural system may be involved in the rewarding properties of psychomotor stimulant and opiate drugs. This neural system corresponds to elements in the ventral tegmental dopamine system with cell bodies in the ventral tegmentum and axon terminals in the nucleus accumbens. Several lines of evidence have shown that psychomotor stimulant reward involves a drug action in the nucleus accumbens and that opiate reward involves a drug action in the ventral tegmentum. Activation of the ventral tegmental system at either synaptic element can produce reinforcement by an enhancement of dopaminergic neurotransmission in the nucleus accumbens. Although additional brain systems may be involved in the rewarding actions of these compounds, their ability to activate the ventral tegmental dopamine system appears to make an important contribution to their net reinforcing impact.