The research published today in the journal Nature was carried out in the United States and was partly funded by the Smokeless Tobacco Research Council, a lobby group funded by the tobacco industry.
As a highly addictive drug, nicotine is normally seen negatively as the substance that gets people hooked on tobacco. But it has been known for a long time that nicotine can improve memory and learning, and the drug has also been linked to arousal, attention and rapid information processing. The drug also affects both working and long-term memory in ways that can cause cravings years after the person has given up smoking.
In Nature, a group of US scientists offers an explanation for these effects. Research done at Baylor College of Medicine, Houston, Texas suggests that nicotine increases the transmission of nerve impulses in the part of the brain involved in learning and memory. It appears to do this by mimicking the effect of a neurotransmitter called acetylcholine, which stimulates the release of other chemicals enabling nerve cells to communicate.
The group worked with rat brains to simulate the process of smoking a cigarette - during which nicotine reaches the brain 10 seconds after taking a puff. They found that when nicotine was detected in arterial blood during smoking, there were also raised levels of a molecule called glutamate, which stimulates nerve-cell activity.
The findings have relevance to Alzheimer's disease, in which a loss of acetylcholine may help explain the poor memory of sufferers. It has long been recognised that forms of dementia are less common in smokers and by developing drugs which have a similar effect to nicotine, it may be possible to exploit these useful effects without the risks of smoking.
It is not the nicotine, but the tars and carbon monoxide among more than 3,000 components of tobacco smoke that are linked with lung cancer and heart disease respectively.
However, a spokeswoman for Action on Smoking and Health (ASH) said: "Any research which is funded by the tobacco industry we would be wary of. Nicotine can have a beneficial effect but we do think that more research should be carried out. We worry that the industry will use the research to promote their products and not distinguish between nicotine and tobacco."Reuse content