Increased anxiety-like behavior in adult rats exposed to nicotine as adolescents.
OBJECTIVE
Twenty percent of adolescents between 12 and 18 years old are regular smokers. Recently developed animal models demonstrate that adolescent nicotine exposure produces behavioral and electrophysiological changes, which persist into adulthood. The purpose of this study was to further define the behavioral effects of nicotine exposure during adolescence.


METHODS
Male 31-36-day-old adolescent rats were administered 5.0 mg/kg/day nicotine using transdermal Nicoderm CQ patches (SmithKline Beecham). During nicotine exposure, motor activity was assessed. Behavior in both standard open field and modified open field was examined 2-3 weeks after exposure ended.


RESULTS
Nicotine exposure significantly enhanced motor activity in nicotine-exposed rats compared with controls, demonstrating the acute stimulatory effects of transdermal nicotine. Two to three weeks after nicotine exposure ended, significantly lower levels of exploratory activity were observed relative to controls in the standard open field. Rats exposed to nicotine during adolescence also retreated to the perimeter of the open field more quickly than control rats. In a modified open field, nicotine exposure reduced approaches to food, contact with food and food intake.


CONCLUSIONS
Taken together, these data suggest that adolescent nicotine exposure may induce an anxiogenic profile, which persists beyond acute nicotine withdrawal. Given the hypothesized role of stress and anxiety in the maintenance of smoking, it could be speculated that anxiety associated with smoking abstinence may play an important role in continued adolescent tobacco use.
Slawecki
Craig J
CJ
Department of Neuropharmacology, CVN-14, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA. cslawecki@scripps.edu
Gilder
Allison
A
Roth
Jennifer
J
Ehlers
Cindy L
CL
D000279:Administration, Cutaneous; D000375:Aging / Q000523:psychology*; D000818:Animals; D001007:Anxiety / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D005247:Feeding Behavior / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018722:Nicotinic Agonists; D009538:Nicotine