SMOKERS may have a point when they say lighting up helps them to concentrate, scientists, in Texas reported yesterday.
They said there was a physical mechanism that underlies known effects of nicotine on memory and learning. Their findings could also shed light on the effects of Alzheimer's disease.
Reporting in the science journal Nature, Dr John Dani and colleagues at Houston's Baylor College of Medicine said nicotine increases transmission of nerve impulses in the hippo-campus, the section of the brain involving learning and memory.
Dr Dani's group, working with rats' brains to simulate the process of smoking a cigarette, found that nicotine mimics the effects of the neurotransmitter acetylcholine, a chemical that helps carry signals across the synapses or spaces between brain cells. Acetylcholine stimulates the release of other neurotransmitters.
In Alzheimer's disease, dementia sets in as acetylcholine disappears from the hippocampus.
. A Philip Morris executive wrote in an internal memo more than 20 years ago that most people "smoke for the narcotic value that comes from the nicotine," a position that counters the company's legal attack on federal regulation of tobacco products as drugs.
Lawyers suing the tobacco industry obtained the memo during pre-trial discovery in Mississippi.
