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Tiny worm provides model for the genetics of nicotine dependence
November 03, 2006ANN ARBOR, Mich.--The unassuming C. elegans nematode worm, a 1-millimeter workhorse of the genetics lab, is quite similar to human beings in its genetic susceptibility to nicotine dependence, according to University of Michigan researchers.
This finding should allow researchers to better understand how nicotine dependence works, and perhaps devise new ways to block the craving that keeps humans smoking cigarettes. Nicotine is the addictive substance in tobacco. Dependence on nicotine drives many of the most preventable causes of death in the U.S. and is a worldwide health problem.
A team led by X.Z. Shawn Xu, assistant research professor at the Life Sciences Institute and assistant professor of physiology at U-M Medical School, has completed a series of experiments which establish that C. elegans can get hooked on nicotine. Like humans, the nicotine-sensitive worms showed acute responses to nicotine exposure, as well as tolerance, sensitization and withdrawal.
"It turns out that worms exhibited behavioral responses to nicotine that parallel those observed in mammals," said Xu, whose name is pronounced Shoo. "But it is much easier to identify novel functions of a gene in worms."
Xu and his team found that the genes known to underlie nicotine dependence in mammals are also present in the worms. Having established worms as a model, the Xu team then tried to identify new genes important for nicotine dependence. They found for the first time that TRP channel genes which enable cells to respond to various external stimuli are a part of the nicotine response.
In fact, when they knocked the TRP gene out of worms, the animals no longer responded to nicotine exposures. But when a new generation of worms had that missing gene replaced by a human version of the TRP gene, the worms returned to being nicotine-sensitive.
"This demonstrates that human TRP genes have the capacity to mediate nicotine dependence, suggesting that human TRP genes are important for nicotine dependence in humans," Xu said.
It also makes TRP genes a potential target for the development of drugs to treat tobacco addiction, and the worms can help in that research. C. elegans can also be used to find other unknown genes critical for nicotine dependence.
University of Michigan
"It turns out that worms exhibited behavioral responses to nicotine that parallel those observed in mammals," said Xu, whose name is pronounced Shoo. "But it is much easier to identify novel functions of a gene in worms."
Xu and his team found that the genes known to underlie nicotine dependence in mammals are also present in the worms. Having established worms as a model, the Xu team then tried to identify new genes important for nicotine dependence. They found for the first time that TRP channel genes which enable cells to respond to various external stimuli are a part of the nicotine response.
In fact, when they knocked the TRP gene out of worms, the animals no longer responded to nicotine exposures. But when a new generation of worms had that missing gene replaced by a human version of the TRP gene, the worms returned to being nicotine-sensitive.
"This demonstrates that human TRP genes have the capacity to mediate nicotine dependence, suggesting that human TRP genes are important for nicotine dependence in humans," Xu said.
It also makes TRP genes a potential target for the development of drugs to treat tobacco addiction, and the worms can help in that research. C. elegans can also be used to find other unknown genes critical for nicotine dependence.
University of Michigan
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Skin color clue to nicotine dependence
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Kids who watch R-rated movies are more likely to smoke
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Penn research probes genetic underpinnings of nicotine addiction
A new study from the Abramson Cancer Center and Department of Psychiatry in the University of Pennsylvania School of Medicine shows that smokers who carry a particular version of a gene for an enzyme that regulates dopamine in the brain may suffer from concentration problems and other cognitive deficits when abstaining from nicotine - a problem that puts them at risk for relapse during attempts to quit smoking.
ADHD appears to increase level of nicotine dependence in smokers
Young people with ADHD are not only at increased risk of starting to smoke cigarettes, they also tend to become more seriously addicted to tobacco and more vulnerable to environmental factors such as having friends or parents who smoke, according to a study from Massachusetts General Hospital reseachers.
Parental warning: second-hand smoke may trigger nicotine dependence symptoms in kids
Parents who smoke cigarettes around their kids in cars and homes beware -- second-hand smoke may trigger symptoms of nicotine dependence in children.
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The Biology of Nicotine Dependence - Symposium No. 152 by CIBA Foundation Symposium (Author) The Biology of Nicotine Dependence Chairman: L. L. Iversen 1990 Nicotine is a potent centrally acting drug that has profound physiological and psychological effects. It is considered to be the main agent in the maintenance of the tobacco smoking habit and is largely responsible for the behavioural and physiological responses to the inhalation of tobacco smoke. This book reviews the progress in identifying nicotinic acetylcholine receptors in the brain. The techniques of molecular biology have been used to characterize these receptors and to investigate the functional differences between receptors composed of different types of subunit. Nicotine interacts with the endocrine system, particularly the corticosteroids. This may be the basis for sex-specific differences in the response to... |
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Nicorette Nicotine Polacrilex Gum, 2 mg, Fruit Chill, 100-Count Box by Nicorette Nicorette Nicotine Gum is bursting with cool fruit flavor, and designed for people who smoke less than 25 cigarettes a day. Each piece contains 94 milligrams of calcium and 11 milligrams of sodium. |
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Medication Treatments for Nicotine Dependence by Tony P. George (Editor) Despite the prevalence of both pharmaceutical and behavioral approaches to encourage cessation, over a billion people still indulge in tobacco. Even in the U.S., where tobacco use is considered a clearly treatable and socially regrettable condition, a significant percentage of individuals remain resistant to treatment modalities. It is believed that the problem lies with the availability, the effectiveness, and the tolerance of the treatments. Thus, the development of new and more effective medications for treating nicotine dependence is an area of significant therapeutic importance, and one made increasingly more viable given our rapidly increasing knowledge about the actions of nicotine and tobacco components on the brain. “We are entering a Renaissance period … that promises to... |
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Nicotine Dependence: Understanding And Applying The Most Effective Treatment Intervention by Charles E. Dodgen (Author) Nicotine consumed via cigarettes is one of the more addictive, as well as destructive, substances of abuse. Most-if not all-smokers desire to stop at some point. This book presents an in-depth review and examination of the available techniques and methods that clinicians can use to effectively treat this condition. It presents the pharmacological treatment methods, specifically those that have demonstrated effectiveness. It includes a useful, detailed, step-by-step, 10-session treatment and assessment model that clinicians can use to develop an individual plan for their clients. |
![The Fagerstrom Test for Nicotine Dependence-Smokeless Tobacco (FTND-ST) [An article from: Addictive Behaviors]](http://ecx.images-amazon.com/images/I/41J08AVSFVL._SL160_.jpg) |
The Fagerstrom Test for Nicotine Dependence-Smokeless Tobacco (FTND-ST) [An article from: Addictive Behaviors] by J.O. Ebbert (Author), C.A. Patten (Author), D.R. Schroeder (Author) This digital document is a journal article from Addictive Behaviors, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: Few nicotine dependence measures have been developed for smokeless tobacco (ST) users. Existing measures are limited by the requirement to rate the nicotine content of ST brands for which data is scarce or non-existent. We modified the Fagerstrom Test for Nicotine Dependence (FTND) for ST users, referred to this scale as the FTND-ST, and evaluated its characteristics in a population of 42 ST users. The correlation between the FTND-ST total score and the serum cotinine concentrations was 0.53... |
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Nicorette Nicotine Polacrilex Gum, 4 mg, Fruit Chill, 100-Count Box by Nicorette Nicorette Nicotine Gum is bursting with cool fruit flavor, and designed for people who smoke 25 or more cigarettes a day. Each piece contains 94 milligrams of calcium and 13 milligrams of sodium. |
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Comparison of the Heavy Smoking Index and of the Fagerstrom Test for Nicotine Dependence in a sample of 749 cigarette smokers [An article from: Addictive Behaviors] by H. Chabrol (Author), M. Niezborala (Author), E. Chastan (Author), J. de Leon (Author) This digital document is a journal article from Addictive Behaviors, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: Nicotine Dependence (FTND) was administered to a sample of 749 adult smokers. The Heavy Smoking Index (HSI) which combines two items of the FTND (the number of cigarettes per day and the time of the first cigarette of the day) was compared to the FTND. A cut-off score equal or greater than 4 on the HSI detected a similar rate of nicotine dependence as a cut-off score equal or greater than 6 on the FTND. HSI had good sensitivity (79.5%) and specificity (96.5%). The concordance between the two instruments was high... |
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Major depression among adolescent smokers undergoing treatment for nicotine dependence [An article from: Addictive Behaviors] by J.D. Killen (Author), T.N. Robinson (Author), S. Ammerman (Author), Hayward (Author) This digital document is a journal article from Addictive Behaviors, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: This is the first study to examine the prevalence and effects of major depression (MDD) in a sample of adolescent smokers (N=211) undergoing treatment for nicotine dependence. We assessed MDD at baseline and end of treatment with the mood disorders portion of the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). Eleven percent of participants reported a history of MDD (6% of males and 21% of females). Study variables did not distinguish those with... |
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Nicorette Gum Starter Kit, 2 mg, 110 pieces (Mint) by Nicorette For those who smoke less than 25 cigarettes a day. Each piece contains: calcium (94 mg), sodium (13 mg). |
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Exploring the association of John Henry active coping and education on smoking behavior and nicotine dependence among Blacks in the USA [An article from: Social Science & Medicine] by A.F. Fernander (Author), C.A. Patten (Author), D.R. Schroeder (Author), Steve (Author) This digital document is a journal article from Social Science & Medicine, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: Although smoking is used as a coping tool in response to stress and Blacks have been found to report smoking more in response to stress than Whites, little research exists that has examined ethno-culturally specific constructs of stress and coping as they relate to smoking behavior and nicotine dependence among Blacks in the USA. This study explored the association between the ethno-culturally interactively defined construct of John Henryism, as well as the individual contributions of John Henry active... |
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