Cocaine can change the brain in ways that can be passed on to male offspring, making them less likely to find the drug rewarding or work hard to get it, according to new research on the epigenetics of drug abuse. The study, made public this week at a meeting of the Society for Neuroscience in Washington, D.C., is the first to show that the chemical effects of cocaine abuse can reach across succeeding generations to cause a beneficial change, by altering how genes are controlled without actually changing the genes themselves. “It confers protectiveness to the rewarding effects of cocaine,” said Nora Volkow, director of the National Institute on Drug Abuse , which funded the research. To study inherited effect of cocaine, researchers at the University of Pennsylvania Medical School mated male rats that were heavy cocaine users to female rats that had never been exposed to the drug. They then kept them separate, to eliminate any influence of the males’ behavior on the pregnant females. The researchers found that the male – but

not female – offspring basically turned up their noses when offered the drug. “To our surprise, the male offspring of dads who took cocaine did not like cocaine as much,” said university neuro-pharmacologist Chris Pierce, who presented the team’s findings during the conference. “They took less cocaine and they liked it less.” The researchers are still working to determine the biochemistry of the inherited change and exactly how it is transmitted to offspring. In part, cocaine may affect the expression of a gene that encodes for a growth factor called brain-derived neurotrophic factor, which is found in higher levels of the prefrontal cortex among rats that find cocaine less rewarding, they reported. But there may be other factors also involved. “Cocaine has re-programmed the sperm in these animals and that information is transmitted to the offspring of these animals, especially the males,” Dr. Pierce said. “It is conferring something beneficial to the offspring, to resist something that is in their environment.”

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Rats That Get No Kick From Cocaine