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Effects of Self‐Administered Oxycodone on Learning and Cognitive Flexibility in Nonhuman Primates
Author(s) -
Kangas Brian D,
Porter Erica N.,
Bergman Jack
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.662.3
Subject(s) - oxycodone , touchscreen , self administration , cognition , opioid , medicine , adverse effect , psychology , cognitive flexibility , pharmacology , anesthesia , neuroscience , computer science , receptor , operating system
Over the past decade, prescription opioid abuse has become a major public health concern. Despite increased prevalence, however, the effects of chronic opioid abuse on cognition‐related behavior remains poorly understood. Previous studies in our laboratory have shown that self‐administration of other abused drugs can have adverse effects on cognitive behavior. Therefore, the present studies employed similar techniques to examine the effects of daily intravenous self‐administered oxycodone. Touchscreen‐based repeated acquisition and discrimination reversal tasks were designed to assay basic features relevant to learning and cognitive flexibility, respectively. Four squirrel monkeys were initially trained to self‐administer oxycodone. A range of doses was evaluated in each subject over 1, 2, and 3‐hour sessions until stable intake was observed. A peak dose of 0.1 mg/kg/inj during 3‐hr sessions yielded maximum daily intake and was used for subsequent conditions. Following 30 self‐administration sessions, subjects were then introduced to the touchscreen tasks. Subjects were placed in a touchscreen chamber immediately following oxycodone self‐administration and learned to discriminate between two novel stimuli (acquisition) for a palatable food reward. Once discrimination acquisition was mastered, subjects then re‐learned the discrimination under conditions where the consequences were switched (reversal). Dose‐response functions revealed orderly increases in oxycodone intake as a function of dose. In addition, extending session durations increased daily intake at all doses examined. Stable levels of oxycodone intake using the peak dose of 0.1 mg/kg/inj were maintained over extended periods of self‐administration (>100 sessions). Results from touchscreen sessions indicated dramatic deleterious effects on learning and reversal in some subjects; however, in other subjects less profound effects were observed. Future studies will investigate the effects of abrupt discontinuation of opioid self‐administration (withdrawal) on discrimination learning and reversal. Support or Funding Information This research was supported by grant K01‐DA035974 (BDK) from the National Institute on Drug Abuse.