Abstract
The purpose of these experiments was to explore the hypothesis that the effects of nicotine on anxiety depend on the time since administration and the duration of treatment. In the social interaction test of anxiety, acute nicotine administration (0.1 mg/kg, subcutaneously) decreased social interaction when rats were tested 5 min after injection, but increased it when they were tested 30 min after injection. Social interaction was also decreased 1 h post-injection, but levels returned to baseline between 3 and 30 h. As these changes were independent of any changes in locomotor activity, nicotine seemed to be having both anxiogenic and anxiolytic effects at different times after injection. An anxiolytic effect was also observed 30 min after the second nicotine injection, and the anxiogenic effect observed 5 min after injection remained after 4 days of nicotine administration. However, after 7 days of nicotine treatment, tolerance was observed to both these effects. When rats were tested 72 h after the last of 7 or 14 days of nicotine treatment, an anxiogenic withdrawal response was observed. Thus, an oppositional mechanism may underlie tolerance to the anxiolytic effects, whereas there is as yet no evidence for this type of mechanism mediating tolerance to the anxiogenic effects.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: 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.
