UI - 000026

AU - Shippenberg TS

AU - Stein C

AU - Huber A

AU - Millan MJ

TI - Motivational effects of opioids in an animal model of prolonged inflammatory pain: Alteration

in the effects of k- but not of m-receptor agonists

AB - IN: Max-Planck-Inst fur Psychiatrie, Martinsried, Fed Rep Germany LA: English AB: A preference

conditioning procedure was used to examine the motivational effects of opioids in naive male rats and male

rats suffering from prolonged pain associated with Freund's adjuvant (FA)-induced inflammation of a

hindlimb. It was found that the mu- opioid agonist morphine functioned as a reinforcer in naive Ss producing

marked preferences for the drug-paired place. Ss injected with FA 7 days prior to conditioning exhibited a

preference for the morphine place. Administration of the kappa- opioid receptor agonist U-69593 to naive

Ss produced dose-related place aversions. The aversive effect of this kappa-agonist was, however, abolished

in FA-treated Ss. Data suggest that kappa- agonists may be effective therapeutic agents in the management

of chronic pain states. (PsycLIT Database Copyright 1989 American Psychological Assn, all rights reserved)

KP: motivational effects of opioids; male rats; animal model of prolonged inflammatory pain AN: 76-21813

SO - Pain 1988;35:179-186