Exposure to nicotine in the womb produces brain changes associated with addictive personality. In a rat study, the equivalent of one cigarette a day during pregnancy produced offspring which as adolescents self-administered more nicotine, ate more fat and drank more alcohol.
Exposure to nicotine in the womb increases the production of brain cells that stimulate appetite, leading to overconsumption of nicotine, alcohol and fatty foods in later life, according to a new study in rats.
Smoking during pregnancy is known to alter fetal brain development and increase the risk of premature birth, low birth weight and miscarriage.
... Sarah Leibowitz, a behavioural neurobiologist at the Rockefeller University in New York, and her colleagues injected pregnant rats with small doses of nicotine — which the researchers say are comparable to the amount a pregnant woman would get from smoking one cigarette a day — and then examined the brains and behaviour of the offspring.
... they found that nicotine increased the production of specific types of neurons in the amygdala and hypothalamus. These cells produce orexin, enkephalin and melanin-concentrating hormone, neuropeptides that stimulate appetite and increase food intake.
Rats exposed to nicotine in the womb had more of these cells and produced more of the neuropeptides than those that were not, and this had long-term consequences on their behaviour. As adolescents, they not only self-administered more nicotine, but also ate more fat-rich food and drank more alcohol.
“These peptide systems stimulate food intake,” says Leibowitz, “but we found that they similarly increase the consumption of drugs and stimulate the brain’s reward mechanisms that promote addiction and substance abuse.”
Leibowitz notes that children whose mothers smoked during pregnancy are more likely to smoke themselves during adolescence and adulthood. Her team's findings suggest a possible mechanism for that.
In earlier work, Leibowitz and her colleagues showed that rats exposed to fat and alcohol in the womb likewise overconsume these substances as adolescents. “Our studies make it very clear that neuronal development in utero is highly sensitive... [emphasis mine]