Scientists at Indiana University have found that significant amounts of the two main components of cannabis, THC and CBD, enter the embryonic brain of mice in utero and impair the mice's ability as adults to respond to fluoxetine, a drug commonly used to treat anxiety and depression and known by the brand name Prozac.
The study suggests that when the developing brain is exposed to THC or CBD, normal interactions between endocannabinoid and serotonin signaling may be diminished as they become adults.
"Hemp-derived CBD is a legal substance in the U.S., and we are in a time of increasing state-level legalization of cannabis. Therefore, use of cannabis components have increased across most levels of society, including among pregnant women," said Hui-Chen Lu—author of the study, director of the Linda and Jack Gill Center, a professor in the Department of Psychological and Brain Sciences in the IU Bloomington College of Arts and Sciences, and adjunct professor in the IU Bloomington College of Arts and Sciences' Department of Biology. "The study marks the beginning of an effort to understand the effects of THC and CBD on the endogenous cannabinoid system in the developing brain and body."
The study was published in Cannabis and Cannabinoid Research and will be a part of the upcoming 2021 Gill Symposium, which will focus exclusively on the topic of cannabis.
Researchers studied four groups of pregnant mice. Some received daily moderate doses of either THC, CBD, or a combination of equal parts THC and CBD; a control group was given placebo injections throughout pregnancy. Using mass spectrometry, IU psychological and brain sciences professor Heather Bradshaw tested embryos and found that CBD and THC both could reach the embryonic brain, determining that the drug was making it past the placenta.