ABSTRACT
This chapter reviews the literature regarding the mechanisms of action by which psychomotor stimulant and opiate drugs produce their reinforcing effects. Neuropharmacological advances that allow for relatively selective inactivation of specific neurochemical systems have made it possible to examine the neurobiological mechanisms for the reinforcing effects of psychomotor stimulant and opiate drugs. Investigations into the neuroanatomical substrates mediating drug reinforcement typically assess changes in self-administration response rates following the production of site- and/or neuronal-specific neurotoxic lesions. Various research strategies have been employed to investigate the neurochemical and neuroanatomical substrates mediating stimulant and opiate reinforcement. In order to interpret the behavioral changes produced by neurochemical and neuroanatomical manipulations, it is important to understand the relationship between drug-maintained behavior and dose per injection. The evidence obtained from self-administration experiments indicates that the reinforcing effects of opiates are attenuated by opiate antagonist pretreatment.
