Receptor subtypes in opioid and stimulant reward.
Studies of the behaviourally-reinforcing actions of opioid and stimulant drugs of abuse are reviewed in an attempt to identify their reward-related brain receptors. We focus on data generated by drug self-administration, brain stimulation reinforcement, and conditioned place preference paradigms. A consistent body of evidence supports a role for mu and delta, but not kappa, receptors in opioid reward. Stimulant reward apparently involves both D1 and D2 receptors; the data favour D2 mediation of stimulant drug reinforcement with a permissive or modulatory role for D1 receptors. The reward-relevant opioid and dopamine receptors, as well as the cannabinoid (marijuana) receptor, share the ability to couple Gi proteins that mediate inhibition of adenylate cyclase and stimulation of K+ conductance. These signal transduction mechanisms thus may be generally implicated in the reinforcing properties of diverse drugs of abuse.
Self
D W
DW
Department of Pharmacology, College of Medicine, University of California, Irvine 92717.
Stein
L
L
D000818:Animals; D009294:Narcotics / Q000494:pharmacology*; D011954:Receptors, Dopamine / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology*; D012201:Reward; D012646:Self Administration; D019966:Substance-Related Disorders / Q000523:psychology
D009294:Narcotics; D011954:Receptors, Dopamine; D011957:Receptors, Opioid