Bernard Le Foll1, Steven R Goldberg. 1. Preclinical Pharmacology Section, Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, Department of Health and Human Services, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA. blefoll@intra.nida.nih.gov.
Abstract
RATIONALE: Conditioned place preference (CPP) procedures provide one measure of potential rewarding effects of abused drugs. Many attempts to induce CPP with nicotine have been unsuccessful. OBJECTIVES: To assess the influence of nicotine dose and stimulus assignment procedure on development of nicotine-induced CPP. METHODS: Initial preferences for one side of a two-compartment apparatus were first determined in Sprague-Dawley rats. In subsequent conditioning trials, the compartment paired with nicotine was the initially preferred side for half of the rats, and the initially non-preferred side for the other half. Rats received either an injection of nicotine (0.01-2 mg/kg SC) before being placed in one compartment (three trials) or saline before being placed in the other compartment (three trials). Control rats had saline injections associated with both compartments. A final test trial with no injection assessed final place preference. RESULTS: Significant CPP were induced by 0.1-1.4 mg/kg doses of nicotine. Nicotine-induced CPP were only apparent when nicotine was paired with the initially non-preferred side. Moreover, a very high dose of nicotine (2 mg/kg) induced conditioned place aversion when paired with the initially preferred side of the apparatus. CONCLUSIONS: Nicotine induced significant CPP across a wide range of doses, in accordance with its role as the primary addictive component of tobacco. Small preferences for one side of the apparatus played a major role in the development of nicotine-induced CPP. These findings suggest that biased procedures may be more suitable than unbiased procedures for evaluation of rewarding effects of nicotine using CPP paradigms.
RATIONALE: Conditioned place preference (CPP) procedures provide one measure of potential rewarding effects of abused drugs. Many attempts to induce CPP with nicotine have been unsuccessful. OBJECTIVES: To assess the influence of nicotine dose and stimulus assignment procedure on development of nicotine-induced CPP. METHODS: Initial preferences for one side of a two-compartment apparatus were first determined in Sprague-Dawley rats. In subsequent conditioning trials, the compartment paired with nicotine was the initially preferred side for half of the rats, and the initially non-preferred side for the other half. Rats received either an injection of nicotine (0.01-2 mg/kg SC) before being placed in one compartment (three trials) or saline before being placed in the other compartment (three trials). Control rats had saline injections associated with both compartments. A final test trial with no injection assessed final place preference. RESULTS: Significant CPP were induced by 0.1-1.4 mg/kg doses of nicotine. Nicotine-induced CPP were only apparent when nicotine was paired with the initially non-preferred side. Moreover, a very high dose of nicotine (2 mg/kg) induced conditioned place aversion when paired with the initially preferred side of the apparatus. CONCLUSIONS:Nicotine induced significant CPP across a wide range of doses, in accordance with its role as the primary addictive component of tobacco. Small preferences for one side of the apparatus played a major role in the development of nicotine-induced CPP. These findings suggest that biased procedures may be more suitable than unbiased procedures for evaluation of rewarding effects of nicotine using CPP paradigms.
Authors: Arlene C Pak; Charles R Ashby; Christian A Heidbreder; Maria Pilla; Jeremy Gilbert; Zheng-Xiong Xi; Eliot L Gardner Journal: Int J Neuropsychopharmacol Date: 2006-08-31 Impact factor: 5.176
Authors: Matthew I Palmatier; Xiu Liu; Gina L Matteson; Eric C Donny; Anthony R Caggiula; Alan F Sved Journal: Psychopharmacology (Berl) Date: 2007-08-05 Impact factor: 4.530