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Evaluation of a Postoperative Pain‐Like State on Motivated Behavior in Rats: Effects of Plantar Incision on Progressive‐Ratio Food‐Maintained Responding
Author(s) -
Warner Emily,
Krivitsky Rebecca,
Cone Katherine,
Atherton Phillip,
Pitre Travis,
Lanpher Janell,
Giuvelis Denise,
Bergquist Ivy,
King Tamara,
Bilsky Edward J.,
Stevenson Glenn W.
Publication year - 2015
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/ddr.21284
Subject(s) - anesthesia , analgesic , sensory system , psychology , medicine , neuroscience
Preclinical ResearchThere has been recent interest in characterizing the effects of pain‐like states on motivated behaviors in order to quantify how pain modulates goal‐directed behavior and the persistence of that behavior. The current set of experiments assessed the effects of an incisional postoperative pain manipulation on food‐maintained responding under a progressive‐ratio (PR) operant schedule. Independent variables included injury state (plantar incision or anesthesia control) and reinforcer type (grain pellet or sugar pellet); dependent variables were tactile sensory thresholds and response breakpoint. Once responding stabilized on the PR schedule, separate groups of rats received a single ventral hind paw incision or anesthesia (control condition). Incision significantly reduced breakpoints in rats responding for grain, but not sugar. In rats responding for sugar, tactile hypersensitivity recovered within 24 hr, indicating a faster recovery of incision‐induced tactile hypersensitivity compared to rats responding for grain, which demonstrated recovery at PD2. The NSAID analgesic, diclofenac (5.6 mg/kg) completely restored incision‐depressed PR operant responding and tactile sensitivity at 3 hr following incision. The PR schedule differentiated between sucrose and grain, suggesting that relative reinforcing efficacy may be an important determinant in detecting pain‐induced changes in motivated behavior. Drug Dev Res 76 : 432–441, 2015. © 2015 Wiley Periodicals, Inc.