The role of drug-associated cues on the maintenance of cocaine self-administration

Abstract

A number of studies have demonstrated the ability cues associated with self-administration of cocaine to elicit drug-seeking. However, the role of these cues in the maintenance of self-administration behavior has received relatively little attention. The present study determined the effect of the presence or absence of a cocaine-associated stimulus on cocaine self-administration (0.25 mg/kg/infusion) during a long-duration self-administration session. Some groups of rats were trained to self-administer cocaine with an associated light stimulus. For others, training was accomplished without the light stimulus. Rates of responding during an 18-hour session were comparable for both groups. For rats trained with the light stimulus, a significant attenuation following the removal of the light stimulus in rates of responding for cocaine was observed. There was no significant alteration in rates of responding when the light stimulus was introduced for rats trained without the light stimulus. These data indicate that the cocaine-associated light stimulus maintained drug-taking behavior in rats that had a previous light-cocaine association. Pretreatment with the kappa opioid agonist, U69593, also attenuated responding but this effect was produced only for animals trained to self-administer cocaine with the light stimulus. Therefore, it seems as thought the kappa opioid agonist, U69593, selectively disrupts responding for the cocaine-associated light stimulus.