[Abstract Title]. - Society for Neuroscience

endocannabinoids. The molecular mechanisms underlying these selective actions are currently
under investigation.
Disclosures: A. Muntoni, None; G. Pillolla, None; A. Luchicchi, None; M. Melis, None; M.
Pistis, None.
Poster
258. Molecular and Neurochemical Basis of Nicotine Addiction
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 258.2/AA5
Topic: C.16.p. Neuroplasticity and addiction
Support: FLADOH 05NIR-594
Title: Differential effects of cannabinoid (CB) 1 receptor antagonist or bupropion in the mossy
fibre reorganization following behavioral sensitization to nicotine in a rat model of noveltyseeking
Authors: *A. BHATTI, C. ISGOR;
Florida Atlantic Univ., BOCA RATON, FL
Abstract: We have previously shown that a novelty-seeking phenotype in the outbred rat has
predictive value in the expression of behavioral sensitization to nicotine. Locomotor reactivity to
a novel environment is used to rank high (HR, locomotor scores ranking in the highest 1/3 rd of
the population) versus low (LR, locomotor scores ranking at the lowest 1/3 rd of the population)
responsiveness. HR rats are shown to express locomotor sensitization to a low dose nicotine
challenge following a high dose of nicotine training and an associated increase in the mossy fibre
terminal field (MF) size. Moreover, we previously showed that a cannabinoid (CB) 1 receptor
antagonist administered during nicotine abstinence reverses the locomotor sensitization to
nicotine challenge in the HR rats. In the present work we investigate effects of CB1 receptor
antagonist and an FDA approved nicotine cessation agent, bupropion, on the mossy fibre
plasticity following nicotine sensitization in the LRHR phenotype. LRHR rats underwent
intermittent nicotine training with 4 injections at a medium dose (0.35 mg/kg s.c.) administered
at 3-d intervals during the peripubertal-juvenile period (postnatal days 28-40). Following
nicotine training, CB1 receptor antagonist AM251 (5 mg/kg; i.p.), bupropion (40 mg/kg; s.c.) or
saline (1 ml/kg; s.c.) were administered on 1 st , 3rd and 5 th day of the 1 wk of abstinence.
Expression of behavioral sensitization to nicotine is assessed in response to a low dose (0.1
mg/kg s.c.) nicotine challenge. Five days after challenge, rats were sacrificed; hippocampi were
sectioned and stained with Timm‟s silver sulfide method. MF size was estimated using