Nicotine Withdrawal Linked to Specific Brain Region
Nicotine withdrawal affects a very specific group of neurons within a very specific brain region, according to a new study.
The latest finding suggests that therapies directed at this groups or brain cells might one day help people quit tobacco.
"We were surprised to find that one population of neurons within a single brain region could actually control physical nicotine withdrawal behaviors," Andrew Tapper of the Brudnick Neuropsychiatric Research Institute at the University of Massachusetts Medical School said in a news release.
For the study, researchers got laboratory mice addicted to nicotine by putting the drug in their water for a period of 6 weeks. When the nicotine was taken away, the mice started scratching and shaking in the way a dog does when it is wet.
After examining the mice's brains researchers found abnormally increased activity in neurons within a single region known as the interpeduncular nucleus.
Researchers also artificially activated brain cells in the interpeduncular nucleus with light and found that the animals showed behaviors that looked like nicotine withdrawal, whether they had been exposed to the drug or not.
The study showed that the opposite was also true: lowering activity in the interpeduncular nucleus alleviated nicotine withdrawal symptoms.
Rsearchers said the latest findings make sense because the interpeduncular nucleus receives connections from other areas of the brain involved in nicotine use and response, as well as feelings of anxiety. This brain region is also saturated with nicotinic acetylcholine receptors that are the molecular targets of nicotine.
Researchers said there are some hints that the latest findings are relevant to other forms of addiction.
"Smoking is highly prevalent in people with other substance-use disorders, suggesting a potential interaction between nicotine and other drugs of abuse," said Tapper. "In addition, naturally occurring mutations in genes encoding the nicotinic receptor subunits that are found in the interpeduncular nucleus have been associated with drug and alcohol dependence."