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Evaluation of pain‐depressed behaviors in preclinical assays of pain and analgesia: Osteoarthritis‐depressed wheel running in rats
Author(s) -
Cormier Jim,
Dunbar Catherine,
Benoit Laura,
Morin Kathryn,
Bilsky Edward J,
Stevenson Glenn W
Publication year - 2009
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.23.1_supplement.742.10
Subject(s) - wheel running , osteoarthritis , medicine , open field , noxious stimulus , morphine , allodynia , hyperalgesia , anesthesia , chronic pain , hindlimb , analgesic , locomotor activity , stimulus (psychology) , pharmacology , nociception , psychology , physical therapy , receptor , alternative medicine , pathology , psychotherapist
Pain stimulates some behaviors (e.g. withdrawal responses) and depresses other behaviors (feeding, locomotion). We are developing methods for testing candidate analgesics using measurements of pain‐depressed behaviors. Such assays may model important aspects of clinical pain and complement traditional assays that measure pain‐stimulated behaviors. We have previously shown that both feeding and open‐field locomotor activity can be reliably suppressed by a sub‐acute noxious stimulus (i.p. injection of acetic acid). The present study extended these findings by assessing the effects of a chronic pain manipulation (monosodium iodoacetate‐induced osteoarthritis) on wheel running in rats. Rats had 24hr voluntary access to running wheels for seven consecutive days. On day eight, rats were given intra‐articular MIA (.32‐3.2mg) into the left hind knee. Wheel running was monitored for 21 consecutive days following MIA administration. MIA produced a concentration‐dependent and prolonged decrease in running wheel activity. Parallel experiments demonstrated that MIA produced equi‐potent and concentration‐dependent tactile allodynia and shifts in hind‐limb weight‐bearing. Studies are currently underway to determine the efficacy and potency of morphine to (1) restore MIA‐depressed wheel running, (2) reverse MIA‐induced tactile allodynia, and (3) restore normal posture. Funded by NIAMS/NIH grant R15 AR054975‐01 (GWS)