Smoking and Nicotine Dependence
Head: Dr. William Corrigall
Studies in the Smoking and Nicotine Dependence Research Unit examine
the mechanisms and processes of tobacco use in preclinical studies with
animals, and with human-experimental research.
Drug Self-Administration
in Animals
Research with animals has been a central component of this section for
a number of years. Our studies use a model in which animals work (e.g.,
pressing a lever) to obtain intravenous infusions of nicotine. This approach
mimics the rapid delivery of nicotine to the brain of a person smoking
a cigarette.
Ongoing research projects using this model have identified novel sites
in the brain at which nicotine acts to maintain drug-taking behaviour.
Local manipulations of neurochemical elements in these brain sites, and
parallel anatomical studies, have shown that certain brain cells are recruited
by nicotine, apparently selectively (compared to drugs such as cocaine).
By discovering the basic elements in nicotine-seeking behaviours, these
studies provide a preclinical platform for medication development. This
well-established line of investigation is funded by the US National Institute
on Drug Abuse.
Preclinical Medication
Development
In collaboration with US-based Addiction Therapies, Inc. we are testing
the efficacy of particular compounds in reducing voluntary self-administration
of nicotine by laboratory rats. Research of this kind allows us to participate
directly in the early development of smoking cessation medications.
Nicotine Dependence
in Adolescents
It has been known for some time that smoking begins during childhood
and adolescence. Despite this knowledge, and a good appreciation of the
psychosocial factors that contribute to the development of addiction,
there has been little information about the biological events that accompany
early smoking.
We have undertaken a series of studies of cigarette smoking in adolescents
aged 12 to 18, who are smoking at different levels of use. In these studies,
we have been measuring smoking behaviour and indices of dependence both
before and after smoking. Progress to date has shown a number of similarities
between cigarette smoking by adolescents and adults, suggesting that established
patterns of smoking develop early. For example, the way a cigarette is
smoked is very similar in adolescents and adults, and abstinence from
smoking has similar effects in adolescents and adults who smoke, especially
in those adolescents who smoke more than a half-pack of cigarettes daily.
However, we have also observed a very clear development of smoking-related
effects in the less-established adolescent smoker, and this development
is related to the amount smoked. For example, as in adults, smoking improves
cognitive performance -- it has subtle effects on information processing.
In adolescents who smoke, these subtle effects of smoking are related
to the individual's recent smoking history, and are well-established indices
of dependence. This progression suggests that smoking assumes an important
role in an adolescent's life at an early stage in cigarette use. Understanding
these effects is valuable to prevention and treatment efforts. This work
has been funded by the Robert Wood Johnson Foundation.
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