Nicotine Withdrawal

[Guest guest]

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NATIONAL INSTITUTES OF HEALTH

National Institute on Drug Abuse

 

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EMBARGOED FOR RELEASE

Wednesday, May 6, 1998

2:00 PM Eastern Time

Mona W. Brown

Sheryl Massaro

(301) 443-6245

 

 

 

 

Severity of Brain Changes

During Nicotine Withdrawal Comparable to Those for Other Drugs of Abuse

 

Dramatic changes in the brain's pleasure circuits during withdrawal from

chronic nicotine use rival the magnitude and duration of similar changes

observed during withdrawal from other abused drugs such as cocaine, opiates,

amphetamines, and alcohol, according to a new study funded by the National

Institute on Drug Abuse (NIDA), National Institutes of Health. Scientists at

The Scripps Research Institute found significant decreases in the

sensitivity of the brains of laboratory rats to pleasurable stimulation

after nicotine administration was abruptly stopped. These changes lasted

several days, and may correspond to the anxiety and depression experienced

by humans for several days after quitting smoking " cold turkey. "

" Understanding these decreases in the brain's sensitivity to pleasurable

stimulation that occur during nicotine abstinence helps explain why it is so

hard for people to stop smoking. This understanding may also help in the

development of better treatments to address the withdrawal symptoms -

depression, anxiety, irritability, and craving - that interfere with

people's attempts to quit smoking, " said Dr. Alan I. Leshner, director of

NIDA. " The similarity to other drugs of abuse emphasizes that there are

common characteristics to withdrawal from all addictive substances, one of

which is a decrease in sensitivity to pleasure. "

 

A research team led by Dr. Athina Markou of The Scripps Research Institute

in La Jolla, California measured the effects of nicotine withdrawal and

abstinence on the brain's sensitivity to pleasurable electrical stimulation.

Researchers allowed rats to self-administer a baseline intensity of

pleasurable electrical pulses and measured " pleasure " (or reward) associated

with stimulation of the area of the lateral hypothalamus, part of the

brain's reward circuitry. Reward sensitivity measures were taken both during

and after administration of nicotine.

 

For one week, the rats were given a steady dose of nicotine that produced

blood levels equivalent to those of an individual smoking one and a half

packs of cigarettes a day. While the nicotine was being administered, the

rats' sensitivity to brain reward remained stable, as indicated by no

significant change in the self-administration of the electrical pulse. When

the rats were taken off nicotine, however, intensities of electrical current

had to be increased by more than 40 percent before the rats again found them

to be pleasurable. Brain reward sensitivity was affected for at least 4 days

and some rats did not return to baseline for over 2 weeks.

 

" These results are comparable to the altered brain reward sensitivity found

also during withdrawal from many other addictive drugs, " said Dr. Markou.

" The results of this research indicate that we have a good animal model to

study the neurobiology of nicotine abstinence and thus assist in the

development of behavioral and pharmacological treatments for nicotine

addiction. " This research was funded in part by Novartis Pharma AG of Basel,

Switzerland. The study, " Dramatic decreases in brain reward function during

nicotine withdrawal, " will be published in the May 7 issue of NATURE.

 

The use of nicotine products is a major preventable cause of death in the

United States. About 62 million Americans age 12 and over are current

cigarette smokers, making nicotine one of the most heavily used addictive

drugs. The scientific facts about nicotine addiction, based on the latest

research, will be the focus of Addicted to Nicotine: A National Research

Forum to be held July 27-28, 1998. The conference, sponsored by NIDA, the

Robert Wood Johnson Foundation, the National Cancer Institute, and the

Centers for Disease Control and Prevention's Office on Smoking and Health

will highlight the sources of nicotine addiction, prevention of tobacco

product use, and state-of-the-art treatment strategies. The conference will

be held at the Natcher Auditorium on the NIH Campus in Bethesda, MD. For

more information, contact the NIDA Press Office.

 

NIDA supports more than 85 percent of the world's research on the health

aspects of drug abuse and addiction. The Institute also carries out a large

variety of programs to ensure the rapid dissemination of research

information and its implementation in policy and practice. Fact sheets on

health effects of drugs of abuse and other topics can be ordered free of

charge in English and Spanish, by calling NIDA Infofax at 1-888-NIH-NIDA

(-644-6432) or 1-888-TTY-NIDA (-889-6432) for the deaf. These fact sheets

and further information on NIDA research and other activities can be found

on the NIDA home page at http://www.nida.nih.gov.

 

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