Ordinary cannabis introduction during pregnancy may cause intellectual lacks and nervousness in posterity

Ordinary cannabis introduction during pregnancy may cause intellectual lacks and nervousness in posterity


  • Post By : Kumar Jeetendra

  • Source: Washington State University

  • Date: 14 Oct,2020

Regular cannabis exposure in rats during pregnancy can cause their offspring to have long-term cognitive deficiencies, asocial behavior, and anxiety later in adulthood.

That is according to a new study by neuroscientists at Washington State University’s Integrative Physiology and Neuroscience unit that provides a rare look at the effects of using cannabis during pregnancy.

“The reality of cannabis study is there is not a great deal of it,” said Halle Weimar, first author on the paper and grad student in the neuroscience program. “This study helps get information out to women so that they can make an educated decision that’s best for them.”

Weimar and her colleagues discovered the offspring of pregnant rats exposed to cannabis vapor were more likely to make regressive errors once they were trained new techniques to get sugar pellets.

Weimar said the study is particularly significant as medicinal and recreational cannabis usage continues to increase among pregnant women as well as the general population.

The study, recently published in the journal Neuropharmacology, utilized a first-of-its-kind e-cigarette technology to deliver cannabis vapor to pregnant female rats throughout their entire gestation period.

“The idea was to use a more clinically relevant model to mirror the way that people use cannabis, specifically how pregnant women use cannabis,” Weimar said.

Researchers also delivered propylene glycol vegetable glycerol mixture, commonly found in vape juice, to research its consequences in rats. A control group was left in their home cage and not subjected to any vapor.

Vapor was administered twice daily to rats in one-hour sessions during pregnancy and breeding.

The research team found significant behavioral changes and cognitive deficits that persisted into adulthood in the offspring of the rats exposed to cannabis.

Using different levers and a cue light, researchers rewarded and trained rats using sugar pellets for pressing a lever paired with the cue light. The rats were then required to change their strategy during test day and instead ignore the cue, which was used as a measure of cognitive flexibility.

“While rats caught on, those whose mothers were exposed to cannabis were more likely to revert to the old pattern and make regressive errors,” Weimar stated. “They also took more trials to learn the rules.”

Female and male juvenile rats whose mothers were exposed to cannabis also participated in much fewer play behaviors. The male rats were particularly hesitant to participate with other rats in their first social introductions.

Moreover, adult rats whose mothers were exposed to cannabis exhibited anxiety-like behaviour in new environments.When placed in a large, elevated maze with open and closed arms, the rats were more likely to stay in the closed arms of the maze and explore the open, exposed arms .

“They often feel safer in closed arms as opposed to rats which are less anxious and prepared to venture into open spaces and take more risks,” Weimar said.

She said the finding is important because it reveals cannabis vapor handled to a rat during pregnancy can cause its offspring to have age-dependent effects into maturity, noting the observation was not noted in rats when they were juveniles.

The researchers noticed changes in the rats’ behavior as pups as well.

Weimar said rats whose mothers were exposed to cannabis made more than 100 more ultrasonic vocalizations, or cries for their mother, compared to the control group, days after birth.

“It is pretty noteworthy since this is one of the only tests you can do that looks at psychological reactivity in neonates and they were far more responsive than the other groups,” Weimar stated.


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