Abstract
The effects of acute nicotine administration (0.09 mg/kg nicotine), chronic nicotine administration (6.3 mg/kg/d nicotine for 14 d), and withdrawal from chronic nicotine administration on fear conditioning in C57BL/6 mice were examined. Mice were trained using two coterminating conditioned stimulus (30 s; 85 dB white noise)--unconditioned stimulus (2 s; 0.57 mA foot shock) pairings and tested 24 h later for contextual and cued fear conditioning. Acute nicotine administration enhanced contextual fear conditioning, chronic nicotine administration had no effect on contextual fear conditioning, and withdrawal from chronic nicotine administration impaired contextual fear conditioning. Plasma nicotine concentrations were similar after acute and chronic treatment and were within the range reported for smokers. During withdrawal, concentrations of nicotine were undetectable. An acute dose of nicotine (0.09 mg/kg) during withdrawal from chronic nicotine treatment reversed withdrawal-associated deficits in contextual fear conditioning. The results suggest that tolerance to the effects of nicotine on contextual fear conditioning develops with chronic nicotine treatment at a physiologically relevant dose, and withdrawal from this chronic nicotine treatment is associated with impairments in contextual fear conditioning. These findings provide a model of how the effects of nicotine on learning may contribute to the development and maintenance of nicotine addiction.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.