COCAINE SELF-ADMINISTRATION AND NALTRINDOLE, A DELTA-SELECTIVE OPIOIDANTAGONIST

RECENT reports from several laboratories have suggested a role for del ta opioid receptors in expressing some of the biochemical and behavior al effects of cocaine. Here, this possibility has been further explore d by evaluating the propensity of rats to self-administer i.v. cocaine in the absence or presence of naltrindole, a selective delta opioid a ntagonist. Following a number of days of stable cocaine intake, and be fore a day's session, naltrindole (3 or 10 mg kg(-1)) reduced pressing for cocaine, regardless of the schedule of reinforcement. These data further support the role of processes associated with delta opioid rec eptors in the ability of cocaine to reinforce its own use.