French Team Publishes Breakthrough Study on Smoking
(Info-France-USA,22 Nov)

A study on the effects of smoking, conducted at France’s INSERM (National Institute for Health and Medical Research) yielded evidence that nicotine intake kills existing brain cells and hinders the production of new ones, scientists announced on May 13. At the head of the team of researchers were scientists Pier-Vincenzo Piazza and Djoher Nora Abrous, who reported their findings in a specialized publication in the United States, The Journal of Neuroscience.

They said the study’s results decisively contradict s former research work contending that smoking could improve cognitive performance, and even claiming that it could impede the onset of dementia or Alzheimer’s. Although these "pro-nicotine" claims were countered afterwards by the results of other research, mostly based on population research and cognitive tests, this is the first study to do so on the basis of biological tests on the brains of living creatures. The INSERM team’s study was conducted on rats. Three of the four groups of animals were allowed to take intravenous doses of nicotine in low (0.02 milligrams per kilogram), medium (0.04 milligrams per kilogram) or high (0.08 milligrams per kilogram) amounts. The fourth group was not allowed any nicotine. The production of new brain cells in the groups taking medium and high doses of the substance decreased at a rate 50 percent greater than it did among the rats which took no nicotine. It was also observed that their existing brain cells were dying at a greater rate than those of the rats in the nicotine-free group.

All three groups of nicotine-taking rodents experienced a sharp drop in production of a protein, PSA-NCAM. PSA-NCAM and new brain cells alike are produced in the dentate gyrus, part of the hippocampus region of the brain. The protein plays an essential part in the brain’s "plasticity," which affects learning and memory capacities.