Duke nicotine research conference examines tobacco addiction

Oct. 12, 2013 @ 07:32 PM

Studies for decades have linked the cravings of cigarette smokers to nicotine.

But researchers are beginning to pick apart the more than 4,000 other substances found in tobacco to find other clues regarding addiction.

The Duke Nicotine Research Conference, in its 19th year, brought together about 80 researchers from as far as California and even Sweden Thursday at the Durham Convention Center to examine the role of non-nicotine tobacco constituents in addiction and treatment.

Jed E. Rose, director of the Duke Center for Smoking Cessation, which also has offices in Charlotte, Raleigh and Winston-Salem, focuses on treatment development and the effects of nicotine and alcohol on the brain. He’s co-inventor of the nicotine skin patch and is now working with Philip Morris International, an international tobacco and cigarette company, to create a “nicotine inhaler” to help reduce the harm of smoking. 

He said researchers are just starting to study the other substances in tobacco through experiments with animal and human models. Duke recently conducted an experiment with rats, in which the animals would press a lever or press their nose to a particular spot to receive a mix of tobacco or nicotine. The rats preferred the tobacco mixture.

“What else is there about tobacco that makes it more addictive than nicotine in isolation?” Rose asked. How can someone be “so addicted to something that doesn’t get them high?”

He also cited a study from a few years ago that made people choose between smoking cigarettes without nicotine and receiving nicotine through an IV. They preferred the act of smoking, Rose said, the “full sensory experience.”

Each year, about 443,000 people die prematurely from smoking or exposure to secondhand smoke and another 8.6 million live with a serious illness caused by smoking, according to the Centers for Disease Control and Prevention. Despite these risks, about 46.6 million U.S. adults smoke cigarettes.

Rose, along with other researchers, is looking into new quit-smoking treatments that will not only take nicotine into account, but also other factors in tobacco that may satisfy cravings.

He said the industry is on the verge of change, when the U.S. Food and Drug Administration starts to more closely regulate e-cigarettes and scientists steer away from the “quit or die” mentality to offer people a clean source of nicotine and other satisfying substances, without the tar, carbon monoxide, formaldehyde, ammonia and other harmful ingredients that come with cigarette smoke.

Researchers spent Thursday presenting their findings, especially in regard to monoamine oxidase (MAO) inhibitors, which block the breakdown of neurotransmitters, or chemical messengers used to communicate between brain cells. MAO inhibitors are found in cigarette smoke.

MAO inhibition drugs are normally used to treat depression and Parkinson’s disease. The question is if smokers are self-medicating, said Joanna Fowler, a senior chemist and director of Brookhaven National Laboratory’s Radiotracer Chemistry, Instrumentation and Biological Imaging Program.

Rose said a smoker’s brain exhibits less MAO activity, and research is linking the inhibitor characteristics of cigarette smoke to a form of anti-depressant. When a smoker quits, they have been known to exhibit signs of depression, he said.

The Duke Center for Smoking Cessation just started a trial that combines a MAO inhibitor with the nicotine patch to see if the mixture satisfies cravings and leads to a more well-rounded treatment of smokers.

Ryan Lanier, chief clinical research scientist at Rock Creek Pharmaceuticals based in Massachusetts, said his company recently conducted a study by giving heavy smokers tobacco lozenges with nicotine and lozenges with anatabine, which is found in cigarette tobacco and smoke and can affect MAO activity.

The tobacco lozenge satisfied the smokers’ cravings more, whereas they preferred the taste and feel of the anatabine, Lanier said.