New understanding of the brain
helps smokers kick the habit
Mar. 20, 2007
There's never been a better time to quit smoking.
Physicians and health advocates have been telling smokers these words for years, with mixed success.
But a new understanding of brain chemistry and human behavior has led to pharmacological and clinical advances that are making the sentiment resonate more today than ever.
Throughout the Bay Area, scientists are studying new pharmacological tools to combat nicotine addiction and physicians are starting to prescribe the first drug on the market designed specifically to curb nicotine addiction.
Methods of quitting, including behavioral interventions, are being refined to boost success rates to help the estimated one in five Americans who smoke to quit the habit for good.
At the heart of the matter is understanding nicotine, the extremely addictive substance that keeps people smoking and punishes those who stop with depression, irritability, insomnia and intense cravings.
"Nicotine plays a role, not just in stimulation, but it enhances the pleasure response to food and other substances," Benowitz said. "That may be important to understand why people keep smoking."
When a smoker inhales, nicotine is carried by the bloodstream to the brain, where it triggers brain receptors to produce the feel-good hormone dopamine. Over time, the receptors change, resulting in a dopamine deficiency when people stop smoking.
Scientists have discovered that a sub-type neuroreceptor, alpha 4 beta 2, is critically involved in nicotine addiction. New drugs are targeting this receptor to stop addiction, Benowitz said.
New drugs, new methods
Chantix, also known as varenicline, was engineered by pharmaceutical giant Pfizer to target this neuroreceptor. Chantix was approved by the Food and Drug Administration a year ago and became available for sale in August.
Chantix partly stimulates nicotine receptors, including alpha 4 beta 2, enabling a low-level release of dopamine, though not as much as a cigarette would. This influx of dopamine blunts painful withdrawal symptoms associated with kicking the habit. Chantix also partially blocks nicotine from being absorbed by the receptors so smoking is less satisfying.
Source: Insidebayarea |
