'Not just a flavoring: Menthol, Nicotine, Combined Desensitize Airway Receptors

 

Menthol acts in combination with nicotine to desensitize receptors in lungs' airways that are responsible for nicotine's irritation, say neuroscientists at Georgetown University Medical Center (GUMC). "We know that a menthol cough drop soothes a scratchy, sore throat. The question we looked at is if and how it works when the irritant is nicotine," says a study author, Kenneth Kellar, PhD, a professor of pharmacology at GUMC. The findings, which represent work by Georgetown University investigators in GUMC's Department of Pharmacology & Physiology, will be presented by Hoai Ton, PhD, a post-doctoral researcher, on Sunday, Nov. 16 at Neuroscience 2014, the Society for Neuroscience's annual meeting in Washington. "This study supports the notion that menthol is not just a flavoring, but has a pharmacologic effect," Kellar says. The U.S. Food and Drug Administration (FDA) is considering restrictions on menthol cigarettes because it has determined that menthol in cigarettes is likely associated with increased initiation and progression to regular cigarette smoking, increased dependence, and reduced success in smoking cessation, especially among African American menthol smokers. But FDA's review of the available research and evidence relating to menthol cigarettes, issued in July 2013, also concluded, "From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is not associated with an increase in disease risk to the user compared to non-menthol cigarette smokers." At the same time, the use of menthol cigarettes is especially high among African-American smokers, and research has shown a higher rate of lung cancer in African American smokers compared to other smokers. "The issue may be that menthol in the presence of nicotine may reduce the irritation enough that a smoker can inhale more deeply, bringing not just nicotine but toxic smoke products farther into the lungs," says co-investigator Gerald Ahern, PhD, an associate professor of pharmacology at GUMC. 'While beyond the scope of this study, it is possible that such deeper inhalation of menthol cigarettes, to the extent it occurs, increases the already substantial health harms from smoking." The researchers say their study provides a better understanding of how menthol affects the function of the α3β4 receptor, one of the most prevalent nicotinic acetylcholine receptors expressed in the peripheral nervous system. These receptors are expressed in airway sensory nerves as well as other neurons. "These receptors are also found in the brain, but we don't know yet what effect menthol has on those receptors, or whether they contribute, in any way, to nicotine addiction," Kellar says. Story Source: The above story is based on materials provided by Georgetown University Medical Center. Note: Materials may be edited for content and length.

'Not just a flavoring: Menthol, Nicotine, Combined Desensitize Airway Receptors

 

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Menthol acts in combination with nicotine to desensitize receptors in lungs' airways that are responsible for nicotine's irritation, say neuroscientists at Georgetown University Medical Center (GUMC).

"We know that a menthol cough drop soothes a scratchy, sore throat. The question we looked at is if and how it works when the irritant is nicotine," says a study author, Kenneth Kellar, PhD, a professor of pharmacology at GUMC.

The findings, which represent work by Georgetown University investigators in GUMC's Department of Pharmacology & Physiology, will be presented by Hoai Ton, PhD, a post-doctoral researcher, on Sunday, Nov. 16 at Neuroscience 2014, the Society for Neuroscience's annual meeting in Washington.

"This study supports the notion that menthol is not just a flavoring, but has a pharmacologic effect," Kellar says.

The U.S. Food and Drug Administration (FDA) is considering restrictions on menthol cigarettes because it has determined that menthol in cigarettes is likely associated with increased initiation and progression to regular cigarette smoking, increased dependence, and reduced success in smoking cessation, especially among African American menthol smokers. But FDA's review of the available research and evidence relating to menthol cigarettes, issued in July 2013, also concluded, "From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is not associated with an increase in disease risk to the user compared to non-menthol cigarette smokers."

At the same time, the use of menthol cigarettes is especially high among African-American smokers, and research has shown a higher rate of lung cancer in African American smokers compared to other smokers.

"The issue may be that menthol in the presence of nicotine may reduce the irritation enough that a smoker can inhale more deeply, bringing not just nicotine but toxic smoke products farther into the lungs," says co-investigator Gerald Ahern, PhD, an associate professor of pharmacology at GUMC. 'While beyond the scope of this study, it is possible that such deeper inhalation of menthol cigarettes, to the extent it occurs, increases the already substantial health harms from smoking."

The researchers say their study provides a better understanding of how menthol affects the function of the α3β4 receptor, one of the most prevalent nicotinic acetylcholine receptors expressed in the peripheral nervous system. These receptors are expressed in airway sensory nerves as well as other neurons.

"These receptors are also found in the brain, but we don't know yet what effect menthol has on those receptors, or whether they contribute, in any way, to nicotine addiction," Kellar says.

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Story Source:

The above story is based on materials provided by Georgetown University Medical Center. Note: Materials may be edited for content and length.

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Menthol cigarettes linked to increased smoking among teens

 

June 20, 2014

University of Waterloo

Teens who use menthol cigarettes smoke more cigarettes per day than their peers who smoke non-menthols, says a new study. The findings mark the first time that menthol cigarettes have been directly linked to elevated nicotine addiction among youth. "The appeal of menthol cigarettes among youth stems from the perception that they are less harmful than regular cigarettes. The minty taste helps mask the noxious properties, but the reality is that they are just as dangerous as any unflavoured cigarette," said the lead author of the paper.

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Teens who use menthol cigarettes smoke more cigarettes per day than their peers who smoke non-menthols, says a new study. The findings from the Propel Centre for Population Health Impact at the University of Waterloo mark the first time that menthol cigarettes have been directly linked to elevated nicotine addiction among youth.

"The appeal of menthol cigarettes among youth stems from the perception that they are less harmful than regular cigarettes. The minty taste helps mask the noxious properties, but the reality is that they are just as dangerous as any unflavoured cigarette," said Sunday Azagba, a scientist at Propel and lead author on the paper.

Published in Cancer Causes and Control, the study found that menthol users smoked an average of 43 cigarettes a week, close to double the 26 smoked by non-menthol users. The study also found that menthol smokers were almost three times more likely to report that they intend to continue smoking in the next year.

Despite the well-documented health risks associated with tobacco use,  high school students from Grades  are current smokers. Research shows that the majority of long-term adult smokers start smoking during their adolescence. The national Youth Smoking Survey has found that 32 per cent of smokers in high school smoke menthols.

"There is a growing concern that the high popularity of menthol cigarettes among youth may hinder the recent progress in preventing other young people from smoking because many of them may experiment with menthol rather than unflavoured brands," said Azagba.

In July 2010, Canada implemented a ban on the sale of most flavoured cigarettes, little cigars and blunt wraps, but not menthol. Alberta is the only province to include a ban on menthol cigarettes in provincial legislation, though it is not yet in force. In April 2014, the European Union (EU) adopted a new Tobacco Products Directive that will see all 28 EU countries implement a ban on menthol cigarettes.

"Our findings indicate that youth smoking of menthol cigarettes is a serious concern," said Azagba. "It's clear moving forward that we need new laws to ban all added flavours in all tobacco products."