Chronic smoking and alcoholism have a higher number of common genetic targets than previously believed.
Four genes expressed in the brain's prefrontal cortex may help explain why smoking and problem drinking so often go together, Australian research suggests.
The four genes were identified by analyzing brain tissue samples from 30 deceased individuals classified into four groups: nonsmoker/nonalcoholic; nonsmoker/alcoholic; smoker/alcoholic; and smoker/nonalcoholic.
As reported in the May issue of Alcoholism: Clinical & Experimental Research, the findings indicate that chronic smoking and alcoholism have a higher number of common genetic targets than previously believed, and the combined effects of nicotine and alcohol may aggravate the long-term neurological effects of both substances.
"Alcohol and nicotine are both addictive drugs. They act on the same brain region, the 'drug reward pathway' or mesocorticolimbic system (MDS)," study co-author Traute Flatscher-Bader, a postdoctoral research officer at the Alcohol Research Unit of the University of Queensland in Brisbane, said in a prepared statement.
"The MDS contains the 'feel-good' neurotransmitter dopamine," the researcher explained. Nicotine and alcohol appear to cause an imbalance within the MDS by artificially increasing dopamine levels through their effects on dopamine-linked brain cells.
"While the long-term effect of alcoholism on the human brain has been investigated, surprisingly little is known about the long-term effect of nicotine on specific regions of the drug reward pathway in the human brain," Flatscher-Bader noted.
The researchers believe the findings could further research into the effects of alcohol and smoking on the body and brain, and especially the brain's addiction centers.
"Future research of these dual effects in other brain regions may eventually lead to therapeutic solutions, gene therapy or pharmaceuticals which may help decrease or reverse these effects, ultimately helping people to stop drinking or stop smoking before it eventually impacts their health," researcher Nikki Zuvela, a doctoral student in molecular neuroscience at the University of Queensland, said in a prepared statement.
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