Source: Rockefeller University
Summary: Researchers in a new study moved one step closer to understanding how nicotine maintains its powerful grip on the brain. They identified specific chemical changes deep in the brain that help drive nicotine addiction.
According to the World Health Organization (WHO), the worldwide death toll from tobacco use continues to climb. It is currently 6 million per year and is expected to go to 8 million by 2030. Many efforts are being put to unlock the secrets of nicotine addiction as nicotine is one of the most difficult drugs to quit. For sure, while 70% of cigarette smokers in the U.S. say they would like to quit, each year only 3% are able to do so successfully. Researchers from the Rockefeller University in a new study move us one step closer to understanding how nicotine maintains its powerful grip on the brain. They identified specific chemical changes deep in the brain that help drive nicotine addiction. The research findings were published in the journal Proceedings of the National Academy of Science.
Nicotine is a potent parasympathomimetic stimulant that works by binding to receptors widely distributed throughout the brain which causes the neurons to release a variety of neurotransmitters mainly dopamine (associated with brain’s pleasure and reward system). The research team investigated how nicotine affects two midbrain structures, the interpeduncular nucleus (IPN) and the medial habenula (MHb) which have not received much attention until recently. Working with mice they found that chronic nicotine consumption alters the functions of a particular population of neurons inside the IPN. These altered brain cells named as Amigo1, appear to promote nicotine addiction by disrupting the communication between the habenula and the IPN. The research team plans to further investigate the Amigo1 brain cells and the chemical changes they trigger, with the ultimate goal of developing new drugs.
Assoc. Prof. Ines Ibanez-Tallon said, “If you are exposed to nicotine over a long period you produce more of the signal-disrupting chemicals and this desensitizes you, that’s why smokers keep smoking” and further added, “What all of this tells us is that the habenula-IPN pathway is important for smoking in humans”.
More Information: Jessica L. Ables et al, “Retrograde inhibition by a specific subset of interpeduncular α5 nicotinic neurons regulates nicotine preference”, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1717506114