Researchers have identified altered neurons in newborns chronically exposed to nicotine in utero.
Exposure to nicotine during pregnancy, whether through maternal smoking or nicotine replacement therapy, has many negative effects on the unborn child. This exposure is associated with an increase in risk of miscarriage, but is also a risk factor for Unexpected Infant Death (MIN), causing 400 to 500 deaths each year in France. Among healthy infants who were exposed to nicotine, researchers have identified several cognitive and neurobehavioral deficits, linked to a modification of the genes.
Unusually high levels of dopamine
To conduct this study, Metin Akay, professor of biomedical engineering and department head, and his research team analyzed the neurons ofchildren chronically exposed to nicotine in utero. We are talking here about dopamine (which produce dopamine) and non-dopaminergic neurons, all of which are found in the part of the brain responsible for addiction, called the ventral tegmental area (VTA).
The researchers noted that the dopaminergic neurons, in response to nicotine exposure during pregnancy, were constantly activated, which results in the release of exceptionally high levels of dopamine in the body. Active dopamine, known as happiness hormone, is a neurotransmitter that carries information between neurons and regulates emotional responses. Concretely, it encourages the action that will lead to the reward. But as it also regulates the feeling of pleasure, it also plays a role in addiction: these children therefore have a greater risk of become addicted.
Possible treatment for addiction
The researchers also explained that a cure for addiction could be found by studying the severely altered dopaminergic neurons in these newborns. “Affected dopamine can cause babies to become addicted to nicotine, but once we understand which genes are altered, which gene regulatory networks are altered, and which gene pathways are altered, we can develop a targeted drug that could be able eliminate addiction in these children“, Akay said. The research team will therefore initiate new work to understand how dopamine from a newborn exposed to nicotine in utero alters gene expression.
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