FLICKR, ESTRES BACHMONTA brain region called the interpeduncular nucleus, nestled deep within the midbrain, is the seat of nicotine withdrawal, according to new research in mice. Andrew Tapper of the University of Massachusetts Medical School and his colleagues used light to stimulate GABAergic neurons within the interpeduncular nucleus to elicit withdrawal symptoms even in mice who had not been exposed to nicotine. “We were surprised to find that one population of neurons within a single brain region could actually control physical nicotine withdrawal behaviors,” Tapper told the Melbourne Herald Sun.
Tapper and his collaborators habituated mice to nicotine by spiking their water with the drug for six weeks. When the researchers then withheld nicotine from those mice, they exhibited the classic symptoms of withdrawal—excessive scratching and shaking among them. They then noted increased activity in GABAergic neurons in the interpeduncular nucleus, which is linked to feelings of anxiety and receives sensory input from a variety of other brain regions. Topper and his colleagues could even replicate nicotine withdrawal symptoms by exciting neurons in the interpeduncular nucleus in mice who had never been exposed to the drug. And they could dampen withdrawal symptoms by dampening the excitability of GABAergic neurons during withdrawal. They published their findings yesterday (November 14) in Current Biology.
The results hint that treatments aimed at the interpeduncular nucleus could help wean users off of nicotine or other drugs of addiction, according to Topper.