April 20, 2004
Rats Exposed To Prenatal Nicotine Suffer Lasting Brain Injury

Teens are known to be more likely to smoke if their mothers smoked during pregnancy. Among the possible explanations for this phenomena could be a genetic predisposition that increased the odds of mothers being smokers in the first place. However, epidemiological studies which have controlled for many factors support the idea of a biological cause that is a result of the prenatal exposure. Dr. Theodore Slotkin of Duke University has produced evidence in a rat model that suggests prenatal nicotine exposure causes brain damage that creates a predisposition to nicotine addiction.

The rats exposed to nicotine before birth suffered loss of brain cells and a decline in brain activity that persisted throughout adolescence and into adulthood, the team found.

When given doses of nicotine for a two-week period as adolescents, the earlier exposed rats showed a weaker brain response in circuits using acetylcholine -- a natural chemical messenger that plays a critical role in learning and memory -- as compared to rats that did not experience the prenatal exposure. Nicotine's activity in the brain stems from its ability to mimic acetylcholine. The earlier exposure also worsened the decline in brain activity during nicotine withdrawal and led to an increase in the amount of brain cell injury induced by the drug, they reported.

"The current study suggests that the lasting neurotoxic effects of prenatal exposure to nicotine from maternal smoking during pregnancy may worsen the long-term consequences of adolescent smoking -- effects that may increase the likelihood that an individual will take up and keep smoking," Slotkin said.

Specifically, the team explained, the reduced response of acetylcholine systems in the adolescent brain following prenatal exposure might lead teens to self-administer nicotine in an attempt to replace the brain's functional loss. Furthermore, that deficient brain response might drive higher cigarette consumption.

Here is the abstract of the paper and that includes a link to the full paper.

Another group of Duke researchers has previously shown in a rat model that initial exposure to nicotine more strongly predisposed the rats toward later nicotine cravings if the initial exposure first happened in adolescence rather than in adulthood. Brains that are still developing are generally more vulnerable to toxins and so this result is not too surprising.

It is also worth noting that hostile personalities are more prone to nicotine addiction. This latest result suggests the possibility that prenatal nicotine exposure might make people more hostile later in life.

Share |      Randall Parker, 2004 April 20 11:57 AM  Brain Addiction

Stefan Jones said at April 20, 2004 1:25 PM:

Man, you're on a tilting at windmills jag today, aren't you?

Windmills with tungsten steel blades that spin at insane speeds and that have loopholes for a corp of lawyers and PR people and resentment-fueled pundits can shoot at you.

* * *

Sometimes, when I'm feeling paranoid, I wonder if these issues are getting ignored because the powers that be sense that there's a need for people who are stunted and short-lived. Like Huxley's Deltas and Epsilons, but poisoned in the womb instead of in their bottles at the Department of Hatcheries and Conditioning.

Randall Parker said at April 20, 2004 1:37 PM:

LOL! Yes, I'm doing pursuing a theme here on brain development and brain damange. A mind truly is a terrible thing to waste.

As for paranoia: Never attribute to malice anything that can be attributed to stupidity.

If it was up to me pregnant women would be tested for nicotine, alcohol, and addictive drugs. Any found to be using would be warned that a second test will wind them in protective detention. I place the future functioning of the brains of the babies ahead of the rights of the mothers. That is how politically incorrect I am.

Bob Badour said at April 24, 2004 8:18 PM:

What would be worse on the fetus? The mother's nicotine use? Or the mother's cortosol released while detained?

I don't know that your suggestion is all that good an idea; though not for politically correct reasons. Remember to beware those unintended consequences!

Randall Parker said at April 24, 2004 8:57 PM:

Bob, I wouldn't put pregnant women in with regular prison inmates. I'd put them in perhaps residential homes with daily drug testing and then move them up into successively more controlled environments depending on necessity.

Bob Badour said at April 25, 2004 8:39 AM:

Randall, I suspect any type of detention or even just the fear of detention would likely cause an increase in stress hormones. Of course, for some women involved with drug use and prostitution or involved with violent abusive partners etc. detention might actually decrease stress hormone levels by providing a safer more supportive environment.

Many women who smoke are probably self-medicating to avoid even worse mental states. Of course, as medical and pharmaceutical technologies advance, we will probably find cost effective, safe treatments for those mental states thereby reducing the need for nicotine use.

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