Father's exposure to cocaine may help their sons, not daughters, build a resistance to drug addiction, according to researchers who found cocaine stimulated physiological changes transferred from one generation to the other.
The findings are based on the experiments conducted by senior author R. Christopher Pierce and colleagues on rats. They self-administered male rats to cocaine for 60 days which were then mated with female rats, unexposed to the drug. The control group was given saline.
Male offspring of the rats exposed to cocaine showed slower cocaine self-administration and took very low amounts of cocaine compared to the control group. However, female offspring of the cocaine exposed rats didn't show any resistance to the drug.
"This study is the first to show that the chemical effects of cocaine use can be passed down to future generations to cause a resistance to addictive behavior, indicating that paternal exposure to toxins such as cocaine can have profound effects on gene expression and behavior in their offspring," Dr. Pierce, associate professor of Neuroscience in Psychiatry at Penn., said in a news release.
Researchers found the control group more desperate to have the drug than male offspring of the cocaine exposed group. The researchers examined brain areas of the male offspring and found high levels of a protein known as brain-derived neurotrophic factor (BDNF) playing an important role in the occurrence.
Cocaine use brings in some epigenetic changes in sperm and may be passed on from the father to the next generation, researchers concluded.
"We were quite surprised that the male offspring of sires that used cocaine didn't like cocaine as much," said Dr. Pierce. "While we identified one change in the brain that appears to underlie this cocaine resistance effect, there are undoubtedly other physiological changes as well and we are currently performing more broad experiments to identify them."
The findings of the study have been published in the Nature Neuroscience.
