A mother's touch may protect against drug cravings later

December 6, 2011 in Neuroscience

An attentive, nurturing mother may be able to help her children better resist the temptations of drug use later in life, according to a study in rats conducted by Duke University and the University of Adelaide in Australia.

A rat mother's attention in actually changes the in the brains of her pups by permanently altering , according to Staci Bilbo, an assistant professor of psychology and at Duke, who led the research. High-touch mothering increased the brain's production of an immune system molecule called Interleukin-10, leaving these better able to resist the temptation of a dose of morphine much later in life.

This is the first study to show how morphine causes a molecular response in the glial cells of the brain's reward centers, which had only recently been identified as part of drug addiction's circuitry. "We set out to find out what that response looks like," Bilbo said.

To program some of the rat pups to produce more IL-10, the researchers used an established technique called the "handling paradigm," in which very young rat pups are removed from their mother's cage for 15 minutes and then returned. "As soon as they're returned, she checks them out vigorously," grooming the pups and cleaning them, Bilbo said. For a control group, another set of pups were never removed. Some of them had more attentive mothers than others, just by .

The animals then were put through a test called the "place preference chamber," a two-roomed cage in which they would be given a dose of morphine if they entered one side, or a dose of saline on the other. Over the next four weeks, the rats were returned to the two-sided chamber three times a week for five minutes, but were never given another dose of morphine. Initially, they all showed a preference for the morphine side, but over time, the handled rats showed little preference, which indicated their craving had been "extinguished," Bilbo said.

About 8 weeks after their first exposure to morphine, the animals were each given a very small dose of morphine to prime craving and then returned to the 2-sided chamber. The non-handled control rats preferred spending time in the morphine chamber; the handled rats still showed no clear preference.

Morphine activates the of the brain to produce inflammatory which signal a reward center of the brain called the nucleus accumbens. But IL-10 works against that inflammation and reward. The more IL-10 the brain produces, the less likely morphine would cause an increase in craving or relapse weeks after the initial experience with the drug.

The brains of the rat pups who experienced high-touch mothering were found to have more active genes for producing IL-10 in the microglial cells of the brain, which apparently "completely knocked out this drug-seeking behavior," Bilbo said. They were producing about four times as much IL-10 as the control animals. "The nurturing moms can profoundly change outcomes," Bilbo said.

This is a change not of the genes themselves, but of the way they are controlled by something called methylation, which can keep a gene's activity suppressed. High-touch mothering removed methylation on the IL-10 gene, making these rats produce more of the anti-inflammatory molecule.

To further prove that IL-10 levels were key to the craving, the researchers used a drug called ibudilast to artificially increase IL-10 production in a group of control rats. These rats experience craving extinction much the same as the high-touch rats.

It's important to note that the genetic modification created by the mothering didn't change the initial rewarding effect of the , it altered the craving for that reward much later, Bilbo said.

Bilbo said her team next wants to look at the long-term effects of maternal stress on the brain's immune response. They'll be working with the Children's Environmental Health Initiative at Duke, which examines real-world environmental health effects in Durham, NC in collaboration with the US Environmental Protection Agency.

More information: "Early-Life Experience Decreases Drug-Induced Reinstatement of Morphine CPP in Adulthood via Microglial-Specific Epigenetic Programming of Anti-Inflammatory IL-10 Expression," Jaclyn M. Schwarz, Mark R. Hutchinson and Staci D. Bilbo. The Journal of Neuroscience, Dec. 6, 2011. DOI -10.1523/JNEUROSCI.3297-11.2011

Provided by Duke University search and more info website

3 /5 (4 votes)  

Rank 3 /5 (4 votes)
Relevant PhysicsForums posts

More news stories

Reducing caloric intake delays nerve cell loss

Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May ...

Neuroscience created 7 hours ago | popularity 5 / 5 (3) | comments 0 | with audio podcast

B vitamins could delay dementia

(Medical Xpress)—Despite spending billions of dollars on research and development, drug companies have been unable to come up with effective treatments for dementia and Alzheimer's Disease (AD). Now, A. ...

Neuroscience created 10 hours ago | popularity 4.9 / 5 (9) | comments 0 | with audio podcast report

Waiting for a sign? Researchers find potential brain 'switch' for new behavior

You're standing near an airport luggage carousel and your bag emerges on the conveyor belt, prompting you to spring into action. How does your brain make the shift from passively waiting to taking action when ...

Neuroscience created 11 hours ago | popularity 5 / 5 (1) | comments 0 | with audio podcast

If you can remember it, you can remember it wrong

(Medical Xpress)—Native peoples in regions where cameras are uncommon sometimes react with caution when their picture is taken. The fear that something must have been stolen from them to create the photo ...

Neuroscience created 12 hours ago | popularity 4.2 / 5 (5) | comments 0 | with audio podcast report

Study shows where scene context happens in our brain

In a remote fishing community in Venezuela, a lone fisherman sits on a cliff overlooking the southern Caribbean Sea. This man –– the lookout –– is responsible for directing his comrades on the water, ...

Neuroscience created 14 hours ago | popularity 4 / 5 (1) | comments 0 | with audio podcast


Insight into the dazzling impact of insulin in cells

Australian scientists have charted the path of insulin action in cells in precise detail like never before. This provides a comprehensive blueprint for understanding what goes wrong in diabetes.

New sleeping pill poised to hit US markets

An experimental sleeping pill from US drug company Merck is effective at helping people fall and stay asleep, according to reviewers at the US Food and Drug Administration, which could soon approve the new drug.

Antidepressant reduces stress-induced heart condition

A drug commonly used to treat depression and anxiety may improve a stress-related heart condition in people with stable coronary heart disease, according to researchers at Duke Medicine.

Drugs found to both prevent and treat Alzheimer's disease in mice

Researchers at USC have found that a class of pharmaceuticals can both prevent and treat Alzheimer's Disease in mice.

Enrichment therapy effective among children with autism, study finds

Children with autism showed significant improvement after six months of simple sensory exercises at home using everyday items such as scents, spoons and sponges, according to UC Irvine neurobiologists.

Study finds vitamin C can kill drug-resistant TB (w/ video)

In a striking, unexpected discovery, researchers at Albert Einstein College of Medicine of Yeshiva University have determined that vitamin C kills drug-resistant tuberculosis (TB) bacteria in laboratory culture. The finding ...