Researchers Discover New Neurons that Play Key Role in Nicotine Addiction

In a recent study published in the journal Nature Neuroscience, scientists from The Scripps Research Institute found that in the core of the brain’s reward system are specific neurons that are active both with use of and withdrawal from nicotine. Until now, this area of the brain where the neurons were found (called the ventral tegmental area, or VTA) had only been associated with the reward system — not stress from withdrawal. Researchers believe the same neurons may be active in response to many addictive drugs, including nicotine. During the study, scientists studied samples from mice and rats that were raised with chronic exposure to nicotine and had develop nicotine dependence — similar to a heavy smoker going through two packs a day. They found that stress producing neurons in the VTA were activated during withdrawal. After examining brain samples from humans, the same stress producing neurons were present in the VTA. “If you look in a text book, these neurons don’t exist in the VTA,” said the lead author of the study. “That changes the whole conceptual framework.” Now that a link has been found between the reward and the stress systems, researchers think of them as working together as one motivational system. The “high” of dopamine motivates a person to keep smoking, and the stress of withdrawal motivates a person not to quite. To read more about this study, click here.