They occupy as much nicotine receptors in the brain

Sep 29, 2008 09:03 GMT  ·  By

It has always been marketed and believed that light cigarettes only deliver smaller quantities of nicotine to the brain receptors than the regular ones. A recent study proves otherwise, specifically that the nicotine impact of the two cigarette types is sensitively similar.

A new UCLA research has proved that the fact according to which light cigarettes are less harmful to people's health is merely a myth. Observable numbers would tend to approve the myth though, since the light type contains about 0.6 to 1 milligram of nicotine, while the regular kind has a nicotine level of 1.2 to 1.4 mg.

Nicotine binds itself to certain brain nerve cells (nicotinic acetylcholine receptors, or nAChRs). When the nAChRs communicate, the nervous impulses chemically travel over gaps between the cells (synapses) via the neurotransmitters, which then bind to the nerve cells' receptive sites (acetylcholine), culminating with the release of dopamine (a chemical which creates the state of pleasure). Nicotine fakes the behavior of acetylcholine, but has the upper hand, since it lasts for longer, thus causing more dopamine to be released, which might explain why it becomes so addictive.

UCLA psychiatry professor Dr. Arthur L. Brody and his team discovered that the amount of nicotine content has little to do with the effect on the brain, as the nicotine in low-level cigarettes occupies approximately the same percentage of the nicotine receptors in the brain as the regular cigarette types. De-nicotinized cigarettes, which only have nicotine levels of 0.5 mg and are currently undergoing testing stages as a possible option for smoking-ceasing treatments, were also taken into consideration in the study. In spite of the reduced amount, the researchers found that it was enough in order to occupy a large percentage of the brain's nicotine receptors.

The study was conducted on 15 smoking subjects and used adapted designs of PET (positron emission tomography) scans in order to trace the nicotine receptors of the brain. The 15 smokers were subjected to three stages: non-smoking, smoking de-nicotinized cigarettes and smoking low nicotine ones. While a previous study of the scientists demonstrated that smoking regular cigarettes yields an occupation of the nicotine receptors in the brain of 88%, the current one showed that the percentage only drops to 79% during smoking low nicotine cigarettes, while still occupying 26% of the receptors when smoking de-nicotinized ones. The study also revealed that, as Brody explains, “inhaling nicotine during smoking is solely responsible for occupancy of brain nicotine receptors,” while the rest of the thousands of other chemicals in the cigarettes only account for a very small percentage of brain receptor occupancy.

“The two take-home messages are that very little nicotine is needed to occupy a substantial portion of brain nicotine receptors,” stated Brody, “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”.