Moms Who Smoked Pot as Teenagers May Have Increased Preference for the Drug in Their Kids
Study in rats suggests marijuana preference transcends generations
Mothers who use marijuana as teenslong before having childrenmay put their future children at a higher risk of drug abuse, new research suggests.
Researchers in the Neuroscience and Reproductive Biology section at the Cummings School of Veterinary Medicine conducted a study to determine the transgenerational effects of cannabinoid exposure in adolescent female rats. For three days, adolescent rats were administered the cannabinoid receptor agonist WIN-55, 212-2, a drug that has similar effects in the brain as THC, the active ingredient in marijuana. After this brief exposure, they remained untreated until being mated in adulthood.
The male offspring of the female rats were then measured against a control group for a preference between chambers that were paired with either saline or morphine. The rats with mothers who had adolescent exposure to WIN-55,212-2 were significantly more likely to opt for the morphine-paired chamber than those with mothers who abstained. The results suggest that these animals had an increased preference for opiate drugs.
The study was published in the Journal of Psychopharmocology and funded by the National Institutes of Health.
"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," said Research Assistant Professor John J. Byrnes, the study's lead author, "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."
Byrnes added that much research is needed before a definitive connection is made between adolescent drug use and possible effects on future children.
The study builds on earlier findings by the Tufts group, most notably a study published last year in Behavioral Brain Research by Assistant Professor Elizabeth Byrnes that morphine use as adolescent rats induces changes similar to those observed in the present study.
Other investigators in the field have previously reported that cannabinoid exposure during pregnancy (in both rats and humans) can affect offspring development, including impairment of cognitive function, and increased risk of depression and anxiety.
Byrnes JJ, Johnson NL, Schenk ME, Byrnes EM. Cannabinoid exposure in adolescent female rats induces transgenerational effects on morphine conditioned place preference in male offspring [published online ahead of print April 15 2012]. J Psychopharmacol, 2012. DOI: 10.1177/0269881112443745
Abstract Behavioral Brain Research
The use of narcotics by adolescent females is a growing problem, yet very little is known about the long-term consequences for either the user or her future offspring. In the current study, we utilized an animal model to examine the transgenerational consequences of opiate exposure occurring during this sensitive period. Female rats were exposed to increasing doses of morphine or its saline vehicle twice daily during adolescent development (postnatal days 3040), after which they remained drug free. At 60 days of age, all females were mated and their adult offspring were tested for anxiety-like behavior and sensitivity to morphine. Specifically, offspring of adolescent morphine (MOR-F1)- or saline (SAL-F1)-exposed mothers were tested for acute locomotor responses in an open field, followed by testing of acute or chronic morphine analgesia on the hot plate. Open field testing indicated alterations in anxiety-like behavior in MOR-F1 female offspring, with effects dependent upon the stage of the estrus cycle. Hot plate testing revealed sex differences in baseline pain threshold and morphine sensitivity in all offspring, regardless of maternal exposure. However, when compared to their SAL-F1 counterparts, MOR-F1 male offspring demonstrated significantly increased sensitivity to the analgesic effects of acute morphine, and developed analgesic tolerance more rapidly following chronic morphine treatment. The findings indicate that prior opiate exposure during early adolescence in females produces sex-specific alterations of both emotionality and morphine sensitivity in their progeny.
About the Cummings School of Veterinary Medicine at Tufts University
Founded in 1978 in North Grafton, Mass., Cummings School of Veterinary Medicine at Tufts University is internationally esteemed for academic programs that impact society and the practice of veterinary medicine; three hospitals and two clinics that combined log more than 80,000 animal cases each year; and groundbreaking research that benefits animal, public, and environmental health.
Original article: http://now.tufts.edu/news-releases/perils-early-substance-abuse