Researchers find inherited genetic variation in nicotine addiction



In a new analysis of tissue biomarkers expressed in ovarian cancer samples, published by PLoS Medicine, David Huntsman and his colleagues from Vancouver General Hospital suggest that substantial differences exist between ovarian cancer subtypes which should be reflected in patient management. Although ovarian cancer is not the most common gynecologic cancer in women, the disease

Full Post: Analysis of tissue biomarkers expressed in ovarian cancer samples

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.

The findings, newly published in the journal Molecular Psychiatry, pave the way to identify novel medications to treat nicotine addiction.

“These findings also provide an important step toward personalized therapy for nicotine addiction by clarifying the role of inherited genetic variation in smoking abstinence symptoms that promote relapse,” says senior author Caryn Lerman, PhD, the Mary W. Calkins Professor in Penn’s Department of Psychiatry and Scientific Director of Penn’s Abramson Cancer Center.

“The new data identify a novel brain-behavior mechanism that plays a role in nicotine dependence and relapse during quitting attempts,” says lead author James Loughead, PhD, assistant professor in the Department of Psychiatry. Loughead and Lerman studied groups of smokers with different inherited variations in a gene which influences levels of dopamine in the prefrontal cortex, the part of the brain that governs working memory and complex decision-making. Spurred by their previous findings that carriers of the catechol-O-methyltransferase (COMT) val gene variant are more susceptible to smoking relapse, the Penn researchers set out to learn if smokers with this genetic background would be more likely to exhibit altered brain function and cognitive deficits during periods of abstinence from smoking.

“Inability to concentrate after quitting is reported by many patients, and this leads them to smoke to reduce these impairments,” Loughead says.

In this study, 33 smokers underwent functional magnetic resonance imaging (fMRI) during periods of both abstinence from smoking and while smoking as usual. During the brain scans, subjects were asked to hold in their minds a series of complex geometric figures. Subjects were also asked to complete a withdrawal symptoms checklist and a questionnaire about their smoking urges. Results showed that smokers with the COMT val/val genotype suffered greater deficits in working memory and brain function when they had refrained from smoking for 14 or more hours, compared to their performance on this task when they had been smoking as usual. This group also exhibited significant increases in withdrawal symptoms during the abstinence challenge session, compared to the other two genotype groups in the study.

These indicators often play a role in the reasons why smokers relapse, and therefore, may lead to the development of personalized therapy to treat smokers who carry this gene variant - a group that is also less responsive to existing therapies for smoking cessation. One method may be to offer carriers of this gene targeted therapies with drugs like COMT inhibitors, some of which have been shown to increase working memory in healthy volunteers.

“Given the prevalence of smoking in the population, translating these findings for medication development could have a significant clinical and public health impact,” Lerman says.

http://www.med.upenn.edu/

Link




Just seeing someone smoke can trigger smokers to abandon their nascent efforts to kick the habit, according to new research conducted at Duke University Medical Center. Brain scans taken during normal smoking activity and 24 hours after quitting show there is a marked increase in a particular kind of brain activity when quitters see photographs

Full Post: Why stopping smoking is hard



Nicotine gum has been in use for over 20 years to help smokers quit abruptly yet close to two-thirds of smokers report that they would prefer to quit gradually. Researchers from the University of Pittsburgh and GlaxoSmithKline Consumer Healthcare have now found that smokers who are trying to quit gradually can also be helped by

Full Post: Nicotine gum effective for gradual smoking reduction and cessation



Tobacco use is more prevalent and smoking cessation less likely among persons with Attention Deficit Hyperactivity Disorder (ADHD). In a study of smokers with attention deficit and hyperactivity symptoms, those who exhibited elevated hyperactivity and impulsivity, with or without inattention, showed lower quit rates after 8 weeks than those with inattention symptoms alone or those

Full Post: Researchers study effect of ADHD on smoking cessation



A collaborative study led by investigators from Massachusetts General Hospital (MGH) is giving what may be the first look at how interactions between genes underlie a key symptom of schizophrenia, impaired working memory. Functional imaging studies reveal how a combination of common variants in two genes is associated with reduced activity of important brain structures

Full Post: Interaction between gene variants may alter brain function in schizophrenia



The study was published in an online Early Edition issue of the Proceedings of the National Academy of Sciences, the week of November 24. Scripps Florida is a division of The Scripps Research Institute. The neuropeptide, hypocretin-1 (Orexin A), may initiate a key signaling cascade, a series of closely linked biochemical reactions, which maintains tobacco

Full Post: Scientists discover that blocking a neuropeptide receptor decreases nicotine addiction