More evidence of the addictive power of nicotine: Researchers at the University of Chicago have found that just a single cigarette's worth of the tobacco-smoke compound can cause dramatic, lasting changes in the brain.
Neurobiologists Daniel McGehee and Huibert Mansvelder found that nicotine binds to receptors on a group of neurons in a part of lab rats' brains called the reward area, which plays an important role in addiction. Those neurons release a chemical that prompts other cells to produce copious amounts of the feel-good hormone dopamine. A one-time exposure to nicotine is all it takes to strengthen the communication between the neurons and the other cells, leaving a chemical memory of the drug and a desire to repeat that first heady buzz. The researchers haven't yet determined whether something similar happens in the human brain. "But if we are correct, drugs that target that receptor and block it could help protect people against addiction," McGehee says. A vaccine against cigarettes? "It's a long shot, I know, but it's possible."