Chi-Chung Kuo1, Hui Shen1, Brandon K Harvey1, Seong-Jin Yu2,1, Theresa Kopajtic2, Josh J Hinkle1, Stephanos Kyrkanides3, Jonathan L Katz1, Yun Wang4,5. 1. Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD, 21224, USA. 2. Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli, Taiwan. 3. Department of Children's Dentistry, Stony Brook University Health Science Center, Stony Brook, NY, 11794-8701, USA. 4. Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli, Taiwan. ywang@intra.nida.nih.gov. 5. Intramural Research Program, National Institute on Drug Abuse, NIH, Baltimore, MD, 21224, USA. ywang@intra.nida.nih.gov.
Abstract
RATIONALE: Repeated administration of methamphetamine (Meth) induces behavioral sensitization which is characterized by a progressive increase in locomotor response after each injection. Previous studies have shown that Mu opioid receptors (MORs) can regulate Meth-mediated behavioral sensitization. However, the reported interactions are controversial; systemic activation of MORs either enhanced or suppressed Meth sensitization. It is possible that alteration of Meth sensitization after systemic administration of MOR ligands reflects the sum of distinct MOR reactions in multiple brain regions. OBJECTIVES: The purpose of the present study was to examine the actions of MORs on Meth sensitization after regionally selective overexpression of human MOR through an AAV6-based gene delivery system. METHOD: We demonstrated that adeno-associated virus (AAV)-MOR increased MOR immunoreactivity and binding in vitro. AAV-MOR or AAV-green fluorescent protein (GFP) was injected into the nucleus accumbens (NAc) or ventral tegmental area (VTA) of adult mice. Two weeks after viral infection, animals received Meth or saline for five consecutive days. Locomotor behavior and striatal dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) level were determined. RESULTS: Repeated administration of Meth progressively increased locomotor activity; this sensitization reaction was attenuated by intra-NAc AAV-MOR microinjections. Infusion of AAV-MOR to VTA enhanced Meth sensitization. AAV-MOR significantly enhanced DA levels in VTA after VTA infection but reduced DOPAC/DA turnover in the NAc after NAc injection. CONCLUSION: Our data suggest a differential modulation of Meth sensitization by overexpression of MOR in NAc and VTA. Regional manipulation of MOR expression through AAV may be a novel approach to control Meth abuse and psychomimetic activity.
RATIONALE: Repeated administration of methamphetamine (Meth) induces behavioral sensitization which is characterized by a progressive increase in locomotor response after each injection. Previous studies have shown that Mu opioid receptors (MORs) can regulate Meth-mediated behavioral sensitization. However, the reported interactions are controversial; systemic activation of MORs either enhanced or suppressed Meth sensitization. It is possible that alteration of Meth sensitization after systemic administration of MOR ligands reflects the sum of distinct MOR reactions in multiple brain regions. OBJECTIVES: The purpose of the present study was to examine the actions of MORs on Meth sensitization after regionally selective overexpression of humanMOR through an AAV6-based gene delivery system. METHOD: We demonstrated that adeno-associated virus (AAV)-MOR increased MOR immunoreactivity and binding in vitro. AAV-MOR or AAV-green fluorescent protein (GFP) was injected into the nucleus accumbens (NAc) or ventral tegmental area (VTA) of adult mice. Two weeks after viral infection, animals received Meth or saline for five consecutive days. Locomotor behavior and striatal dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) level were determined. RESULTS: Repeated administration of Meth progressively increased locomotor activity; this sensitization reaction was attenuated by intra-NAc AAV-MOR microinjections. Infusion of AAV-MOR to VTA enhanced Meth sensitization. AAV-MOR significantly enhanced DA levels in VTA after VTA infection but reduced DOPAC/DA turnover in the NAc after NAc injection. CONCLUSION: Our data suggest a differential modulation of Meth sensitization by overexpression of MOR in NAc and VTA. Regional manipulation of MOR expression through AAV may be a novel approach to control Meth abuse and psychomimetic activity.
Entities:
Keywords:
AAV; Methamphetamine; Mu opioid receptor; Sensitization
Authors: Stephanos Kyrkanides; Paolo M Fiorentino; Jen-nie H Miller; Yanjun Gan; Yu-Ching Lai; Solomon S Shaftel; J Edward Puzas; Maria G Piancino; M Kerry O'Banion; Ross H Tallents Journal: Arthritis Rheum Date: 2007-06