Kappa Opioid Receptor-Mediated Disruption of Novel Object Recognition: Relevance for Psychostimulant TreatmentJason J. Paris, Kate J. Reilley and Jay P. McLaughlin*
Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
- *Corresponding Author:
- Jay P. McLaughlin
Torrey Pines Institute for Molecular Studies
11350 SW Village Parkway
Port St. Lucie, FL 34987, USA
Tel: (772) 345-4715
Fax: (772) 345-3649
E-mail: [email protected]
Received November 16, 2011; Accepted December 20, 2011; Published December 24, 2011
Citation: Paris JJ, Reilley KJ, McLaughlin JP (2011) Kappa Opioid Receptor- Mediated Disruption of Novel Object Recognition: Relevance for Psychostimulant Treatment. J Addict Res Ther S4:007. doi:10.4172/2155-6105.S4-007
Copyright: © 2011 Paris JJ, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Kappa opioid receptor (KOR) agonists are potentially valuable as therapeutics for the treatment of psychostimulant reward as they suppress dopamine signaling in reward circuitry to repress drug seeking behavior. However, KOR agonists are also associated with sedation and cognitive dysfunction. The extent to which learning and memory disruption or hypolocomotion underlie KOR agonists’ role in counteracting the rewarding effects of psychostimulants is of interest. C57BL/6J mice were pretreated with vehicle (saline, 0.9%), the KOR agonist (trans)-3,4-dichloro-N-methyl-N-[2-(1- pyrrolidinyl)-cyclohexyl] benzeneacetamide (U50,488), or the peripherally-restricted agonist D-Phe-D-Phe-D-lle-D-Arg- NH 2 (ffir-NH 2 ), through central (i.c.v.) or peripheral (i.p.) routes of administration. Locomotor activity was assessed via activity monitoring chambers and rotorod. Cognitive performance was assessed in a novel object recognition task. Prolonged hypolocomotion was observed following administration of 1.0 and 10.0, but not 0.3 mg/kg U50,488. Central, but not peripheral, administration of ffir-NH 2 (a KOR agonist that does not cross the blood-brain barrier) also reduced motor behavior. Systemic pretreatment with the low dose of U50,488 (0.3 mg/kg, i.p.) significantly impaired performance in the novel object recognition task. Likewise, ffir-NH 2 significantly reduced novel object recognition after central (i.c.v.), but not peripheral (i.p.), administration. U50,488- and ffir-NH 2 -mediated deficits in novel object recognition were prevented by pretreatment with KOR antagonists. Cocaine-induced conditioned place preference was subsequently assessed and was reduced by pretreatment with U50,488 (0.3 mg/kg, i.p.). Together, these results suggest that the activation of centrally-located kappa opioid receptors may induce cognitive and mnemonic disruption independent of hypolocomotor effects which may contribute to the KOR-mediated suppression of psychostimulant reward.