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Pot During Pregnancy May Harm Fetal Brain

Scientists may have figured out how marijuana use during pregnancy harms the fetal brain.

Basically, marijuana's active ingredient, tetrahdyrocannabinol (THC), may interfere with the development of nerve cells, according to the molecular biologist Tibor Harkany, PhD, who works at the Karolinska Institute in Stockholm, Sweden.

According to the National Institute on Drug Abuse (NIDA), previous research
has shown that some children born to women who abused marijuana during
pregnancy may show signs of neurological problems in development and problems with memory and attention.

Using cell cultures from mice and frogs, Harkany and colleagues studied a certain type of receptor in the brain. Those receptors latch onto chemicals called endocannabinoids.

The researchers explain that in a fetus, those receptors guide the development of axons, which are the long fibers of nerve cells. As the
fetal brain develops, axons position themselves so they can communicate with
each other.

But that process goes awry in mice with genes for impaired cannabinoid
receptors. Those mice's axons didn't position themselves properly in Harkany's study. That could create communication problems between axons.

THC may mimic those effects in the fetal brain when used during pregnancy,
note Harkany and colleagues. However, they didn't directly test that theory.

The study appears in the journal Science.

By Miranda Hitti
Reviewed by Louise Chang
©2007 WebMD, Inc. All rights reserved

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