Mom's Marijuana Use May Influence Future Offsprings' Drug Use

Deborah Brauser

June 07, 2012

June 7, 2012 — Female teen users of cannabis may be increasing the risk for opioid use in their future offspring, new research suggests.

In a new rodent model study, male rats whose mothers were exposed during adolescence to the cannabinoid receptor agonist WIN-55,212-2 were significantly more likely to choose a morphine-paired chamber, as opposed to a chamber paired with saline, than their counterparts whose mothers were not exposed to the cannabinoid.

This effect was significant in both the adolescent and the adult male offspring, report investigators from the Cummings School of Veterinary Medicine at Tufts University in North Grafton, Massachusetts.

"Our main interest lies in determining whether substances commonly used during adolescence can induce behavioral and neurochemical changes that may then influence the development of future generations," lead author John J. Byrnes, MD, from Tufts' Department of Biomedical Sciences, Section of Neuroscience and Reproductive Biology, said in a release.

"We acknowledge that we are using rodent models, which may not fully translate to the human condition. Nevertheless, the results suggest that maternal drug use, even prior to pregnancy, can impact future offspring," added Dr. Byrnes.

Still, the investigators note that more research is needed before a definitive connection can be made.

The study was published online April 19 in the Journal of Psychopharmacology.

Transgenerational Effects

The researchers report that past studies have shown that cannabinoid exposure during pregnancy can lead to developmental problems in both human and rat offspring, including impaired cognitive function and increased risk for depression and anxiety.

In a study published last year in Behavioral Brain Research, Dr. Byrnes and colleagues found that rats' exposure to opioids during adolescence was associated with anxiety-like behavior and increased sensitivity to morphine in their adult offspring.

For the current study, the investigators sought to examine the transgenerational effects of adolescent cannabinoid use.

A group of female adolescent rats (30 days of age, n = 16) were injected with WIN-55,212-2 twice daily for 3 days and then mated when they were 60 days of age.

WIN-55,212-2 is a substance that causes similar effects in the brain as tetrahydrocannabinol (THC), the active ingredient in marijuana.

Both the adolescent (age, 40 days) and adult (age, 60 days) male offspring were then measured against a control group of matched male rats of mothers who had not been exposed to the substance.

All offspring were assessed for their preference for chambers paired with morphine or with saline.

More Research Needed

Results showed that in both adolescence and adulthood, the male rats whose mothers had been exposed to the study substance were significantly more likely to choose the chamber paired with morphine than those whose mothers were not exposed to the substance.

At the adolescent timepoint, there was "a significant interaction between morphine dose and maternal drug history (P = .03)," report the investigators.

At the adult timepoint, the offspring of exposed mothers also showed a significant effect of morphine dose on chamber choice (P < .001).

"The results suggest that these animals had an increased preference for opiate drugs," write the investigators in the release.

"These effects occurred in the absence of any direct exposure to this compound in utero, and provide evidence for transgenerational effects...even in the absence of continued use during pregnancy," they add.

They note that future studies will need to be done to determine whether similar effects can be observed in female offspring and "whether the observed effects represent direct or indirect epigenetic processes."

The study was supported by grants from the National Institutes of Health. The study authors have disclosed no relevant financial relationships.

J Psychopharmacol. Published online April 19, 2012. Abstract


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