Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Do 'light' cigarettes deliver less nicotine to the brain than regular cigarettes?

30.09.2008
For decades now, cigarette makers have marketed so-called light cigarettes — which contain less nicotine than regular smokes — with the implication that they are less harmful to smokers' health. A new UCLA study shows, however, that they deliver nearly as much nicotine to the brain.

Reporting in the current online edition of the International Journal of Neuropsychopharmacology, UCLA psychiatry professor Dr. Arthur L. Brody and colleagues found that low-nicotine cigarettes act similarly to regular cigarettes, occupying a significant percentage of the brain's nicotine receptors.

Light cigarettes have nicotine levels of 0.6 to 1 milligrams, while regular cigarettes contain between 1.2 and 1.4 milligrams.

The researchers also looked at de-nicotinized cigarettes, which contain only a trace amount of nicotine (0.05 milligrams) and are currently being tested as an adjunct to standard smoking-cessation treatments. They found that even that low a nicotine level is enough to occupy a sizeable percentage of receptors.

"The two take-home messages are that very little nicotine is needed to occupy a substantial portion of brain nicotine receptors," Brody said, "and cigarettes with less nicotine than regular cigarettes, such as 'light' cigarettes, still occupy most brain nicotine receptors. Thus, low-nicotine cigarettes function almost the same as regular cigarettes in terms of brain nicotine-receptor occupancy.

"It also showed us that de-nicotinized cigarettes still deliver a considerable amount of nicotine to the brain. Researchers, clinicians and smokers themselves should consider that fact when trying to quit."

In the brain, nicotine binds to specific molecules on nerve cells called nicotinic acetylcholine receptors, or nAChRs. When nerve cells communicate, nerve impulses jump chemically across gaps between cells called synapses by means of neurotransmitters. The neurotransmitters then bind to the receptor sites on nerve cells — in the case acetylcholine resulting in the release of a pleasure-inducing chemical called dopamine. Nicotine mimics acetylcholine, but it lasts longer, releasing more dopamine.

"It can cause specific neurons to communicate and thus increases dopamine for an extended period of time," Brody said. "Most scientists believe that's one key reason why nicotine is so addictive."

In an earlier study, researchers determined that smoking a regular, non-light cigarette resulted in the occupancy of 88 percent of these nicotine receptors. However, that study did not determine whether inhaling nicotine or any of the thousands of other chemical found in cigarette smoke resulted in this receptor occupancy. The central goal of the present study was to determine if factors associated with smoking — other than nicotine — resulted in nAChR occupancy.

The authors reasoned that if nicotine is solely responsible for receptor occupancy, then smoking a de-nicotinized cigarette or a low-nicotine cigarette would result in the occupancy of roughly 23 percent and 78 percent of nicotine receptors, respectively, based on the cigarettes' nicotine content.

"That would still be substantial," Brody said.

Fifteen smokers participated in the study. Each was given positron emission tomography (PET) scans, a brain-imaging technique that uses minute amounts of radiation-emitting substances to tag specific molecules. In this case, the tracer was designed to bind to the nicotine receptors in the brain.

The researchers could then measure what percentage of the tracer was displaced by nicotine when the research subjects smoked. In total, 24 PET scans were taken of participants' brains before and after three different conditions: not smoking, smoking a de-nicotinized cigarette and smoking a low-nicotine cigarette.

The PET data showed that smoking a de-nicotinized cigarette and a low-nicotine cigarette occupied 26 percent and 79 percent of the receptors, respectively, which was very close to what the researchers had originally estimated.

"Given the consistency of findings between our previous study with regular cigarettes and the present study — that showed us that inhaling nicotine during smoking is solely responsible for occupancy of brain nicotine receptors," Brody said.

In addition to Brody, other authors of the study were Mark A. Mandelkern, Matthew R. Costello, Anna L. Abrams, David Scheibal, Judah Farahi, Edythe D. London, Richard E. Olmstead, Jed E. Rose and Alexey G. Mukhin. The researchers report no conflicts of interest. Rose, from the Duke University School of Medicine, has received research support for a study unrelated to the present paper from Vector Tobacco Inc., the manufacturer of Quest cigarettes.

The research was supported by the National Institute on Drug Abuse, the Veterans Administration, the Tobacco-Related Disease Research Program, the National Alliance for Research on Schizophrenia and Depression, and the Office of National Drug Control Policy.

Mark Wheeler | EurekAlert!
Further information:
http://www.mednet.ucla.edu

More articles from Health and Medicine:

nachricht Fast-tracking T cell therapies with immune-mimicking biomaterials
16.01.2018 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht Dengue takes low and slow approach to replication
12.01.2018 | Duke University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

White graphene makes ceramics multifunctional

16.01.2018 | Materials Sciences

Breaking bad metals with neutrons

16.01.2018 | Materials Sciences

ISFH-CalTeC is “designated test centre” for the confirmation of solar cell world records

16.01.2018 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>