Nicotine and cocaine activate the same brain receptors

Kathleen Blanchard's picture
Addiction, cocaine and nicotine
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Neuroscientists say nicotine and cocaine activate the same area of the brain, explaining their highly addictive effects. Scientists say even though the two feel very different, they both stimulate reward pathways in the brain that cause permanent changes.

How does nicotine leads to addiction?

The findings, published in The Journal of Neuroscience, point to similar mechanisms of how cocaine and nicotine “hijack” the brain’s circuitry, leading to addiction.

Danyan Mao, PhD, postdoctoral researcher at the University of Chicago Medical Center explains understanding what happens in the brain to make a person desire a second cigarette is important for finding ways to treat nicotine addiction.

Daniel McGehee, PhD, neuroscientist and associate professor in the Department of Anesthesia & Critical Care at the Medical Center says, "We know that a single exposure to physiologically relevant concentrations of nicotine can lead to changes in the synaptic drive in the circuitry that lasts for several days. That idea is very important in how addiction forms in humans and animals.”

For their experiment, researchers bathed slices of rat brain in a nicotine solution for fifteen minutes. After four hours, electrophysiology studies found nicotine promotes plasticity in a region of the brain called the ventral tegmental area (VTA) that releases dopamine, a brain chemical associated with reward and pleasure.

Experiment shows cocaine and nicotine work on same brain circuitry

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A surprising finding was cocaine and nicotine both excite the same reward pathway in the brain that, if blocked, could lead to addiction prevention and treatment.

"We know without question that there are big differences in the way these drugs affect people," McGehee said. "But the idea that nicotine is working on the same circuitry as cocaine does point to why so many people have a hard time quitting tobacco, and why so many who experiment with the drug end up becoming addicted."

McGehee explains targeting dopamine may be an option for treating drug addiction. The challenge is bypassing dopamine receptors that leads to healthy behavior.

Nicotine and cocaine stimulate the D5 receptor, and McGehee explains, “currently-known blockers of the receptor also block another dopamine receptor, D1, that is important for normal, healthy motivation and movement.”

The study shows nicotine and cocaine stimulate the same reward pathway in the brain, explaining why it’s so difficult to curb nicotine addiction that the researchers say are persistent. More studies are planned to understand the long-term effects of nicotine on the brain’s plasticity.

Image source: Morguefile

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