Washington: Attentive, nurturing mothers may protect their children against drug addiction during later stages of life, a new study has suggested.
According to a study in rats conducted by Duke University and the University of Adelaide in Australia, a rat mother’s attention in early childhood actually changes the immune response in the brains of her pups by permanently altering genetic activity.
High-touch mothering increased the brain’s production of an immune system molecule called Interleukin-10, leaving these rats better able to resist the temptation of a dose of morphine much later in life.
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,” Staci Bilbo, an assistant professor of psychology and neuroscience at Duke, who led the research said.
For a control group, another set of pups was never removed. Some of them had more attentive mothers than others, just by natural variation.
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.
Bilbo said that 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’.
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.