title: Long-term effects of juvenile nicotine exposure on abstinence-related social anxiety-like behavior and amygdalar cannabinoid receptor 1 (CB1R) mRNA expression in the novelty-seeking phenotype.
abstract: A rat model of novelty-seeking phenotype predicts vulnerability to nicotine relapse where locomotor reactivity to novelty is used to rank high (HR) versus low (LR) responders. Present study investigates implication of cannabinoid receptor 1 (CB1R) in the basolateral (BLA) and the central (CeA) nuclei of amygdala in behaviorally sensitizing effects of nicotine and accompanying social anxiety following juvenile nicotine training and a 1- or 3-wk injection-free period in the novelty-seeking phenotype. Sprague-Dawley rats were phenotype screened, and received four, saline (1 ml/kg; s.c) or nicotine (0.35 mg/kg; s.c) injections, followed by a 1- or 3-wk injection-free period. Subsequently, animals were challenged with a low dose of nicotine (0.1 mg/kg; s.c.), subjected to the social interaction test and sacrificed. In situ hybridization histochemistry was used to assess CB1R messenger RNA (mRNA) levels in the amygdala. Nicotine pre-trained HRs displayed expression of locomotor sensitization to nicotine challenge along with enhanced social anxiety compared to saline pre-trained controls following a 1- or 3-wk injection-free period. HR-specific behavioral effects were accompanied by decreased CB1R mRNA levels in the CeA and the BLA following a 1-wk injection-free period. Decreased CB1R mRNA levels in both compartments of the amygdala were also observed following nicotine challenge in saline pre-trained HRs after a 3-wk injection-free period compared to HRs after a 1-wk injection-free period. These findings show robust, long-lasting expression of behavioral sensitization to nicotine in HRs associated with changes in amygdalar CB1R mRNA as a potential substrate for abstinence-related anxiety.
authors: Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL 33431, USA.
authors: Cigdem
authors: C
authors: Aydin
authors: Ozge
authors: O
authors: Oztan
authors: Ceylan
authors: C
authors: Isgor
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001007:Anxiety / Q000139:chemically induced / Q000378:metabolism*; D004334:Drug Administration Schedule; D005106:Exploratory Behavior / Q000187:drug effects*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009538:Nicotine / Q000008:administration & dosage / Q000494:pharmacology*; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D043884:Receptor, Cannabinoid, CB1 / Q000096:biosynthesis*; D012919:Social Behavior
chemical_list: C543264:Cnr1 protein, rat; D043884:Receptor, Cannabinoid, CB1; D009538:Nicotine