In 2000, a team from the same laboratory demonstrated how the first exposure to nicotine can create an enduring memory trace, which instills the desire to repeat the experience and amplifies the pleasing effects of subsequent nicotine exposure. The current paper reveals how nicotine prolongs the reward period by disabling the system that counterbalances the drug's pleasant effects.
The reinforcing effect of nicotine is the primary reason people cannot quit smoking, despite widespread awareness that smoking causes cancer, heart disease, stroke, emphysema, bronchitis, vascular disease, cataracts and impotence. The World Health Organization attributes 4 million deaths each year to tobacco use.
It would be difficult to design a better drug to promote addiction to this horrible habit, said neurobiologist Daniel McGehee, Ph.D., assistant professor in the department of anesthesia and critical care at the University of Chicago and director of the study. It takes only a few exposures to create a lasting memory of the rewards of smoking, which are reinforced by each cigarette smoked. Now we find that nicotine also suppresses the brain's efforts to limit that pleasure."
The brain reward areas serve to acknowledge and reinforce beneficial behaviors, for example eating when you're hungry. Specialized nerve cells encourage the body to repeat pleasing behaviors by releasing dopamine, the neurotransmitter associated with pleasant feelings, into these reward areas. That was good, is the basic message of increased dopamine levels. Do it again.
Unfortunately, drugs of abuse such as nicotine
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Contact: John Easton
jeaston@uchospitals.edu
773-702-6241
University of Chicago Medical Center
13-Mar-2002