Behavioral functions of narcotic antagonists: response drug contingencies

Behavioral effects of the narcotic antagonists naloxone are discussed in terms of stimulus functions. As an eliciting stimulus, the effects of naloxone depend on prior administration of narcotic. Administered independently of responding, naloxone can increase or decrease rates of narcotic reinforced responding depending on the dose of naloxone. When naloxone is administered as a consequence of narcotic self injection, the future probability of that behavior is reduced; thus, naloxone can function as a punishing stimulus. As a negatively reinforcing stimulus, naloxone can maintain behavior which terminates or prevents delivery in morphine dependent monkeys. In animals with previous naloxone avoidance escape experience, unavoidable inescapable injections of naloxone produce increases in avoidance escape response rates. In these animals, responding subsequently can be maintained, at least temporarily, when naloxone is administered only as the consequence of responding.