The duration of nicotine withdrawal-associated deficits in contextual fear conditioning parallels changes in hippocampal high affinity nicotinic acetylcholine receptor upregulation

NEUROPHARMACOLOGY

卷:62

Article

Gould, Thomas J.¹  Portugal, George S.¹  Andre, Jessica M.¹  Tadman, Matthew P.²  Marks, Michael J.²  Kenney, Justin W.¹  Yildirim, Emre¹  Adoff, Michael¹ 

[1] Temple Univ, Dept Psychol, Neurosci Program, Philadelphia, PA 19122 USA

[2] Univ Colorado, Inst Behav Genet, Boulder, CO 80303 USA

关键词: Nicotine;    Addiction;    Acetylcholine;    Learning;    Withdrawal;    Receptor binding;   

DOI  :  10.1016/j.neuropharm.2012.01.003

来源: Elsevier

【 摘 要 】

A predominant symptom of nicotine withdrawal is cognitive deficits, yet understanding of the neural basis for these deficits is limited. Withdrawal from chronic nicotine disrupts contextual learning in mice and this deficit is mediated by direct effects of nicotine in the hippocampus. Chronic nicotine treatment upregulates nicotinic acetylcholine receptors (nAChR); however, it is unknown whether upregulation is related to the observed withdrawal-induced cognitive deficits. If a relationship between altered learning and nAChR levels exists, changes in nAChR levels after cessation of nicotine treatment should match the duration of learning deficits. To test this hypothesis, mice were chronically administered 6.3 mg/kg/day (freebase) nicotine for 12 days and trained in contextual fear conditioning on day 11 or between 1 to 16 days after withdrawal of treatment. Changes in [I-125]-epibatidine binding at cytisine-sensitive and cytisine-resistant nAChRs and chronic nicotine-related changes in 54, alpha 7, and 132 nAChR subunit mRNA expression were assessed. Chronic nicotine had no behavioral effect but withdrawal produced deficits in contextual fear conditioning that lasted 4 days. Nicotine withdrawal did not disrupt cued fear conditioning. Chronic nicotine upregulated hippocampal cytisine-sensitive nAChR binding; upregulation continued after cessation of nicotine administration and the duration of upregulation during withdrawal paralleled the duration of behavioral changes. Changes in binding in cortex and cerebellum did not match behavioral changes. No changes in alpha 4, alpha 7, and 132 subunit mRNA expression were seen with chronic nicotine. Thus, nicotine withdrawal-related deficits in contextual learning are time-limited changes that are associated with temporal changes in upregulation of high-affinity nAChR binding. (C) 2012 Elsevier Ltd. All rights reserved.

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