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How Pot Harms Fetal Brain Development

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

They included Tibor Harkany, PhD, who works in Stockholm, Sweden, at the
Karolinska Institute's molecular neurobiology division.

Harkany's team studied mice and cell cultures from frogs.

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.

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 fibersB 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

The study appears in the journal Science.

By Miranda Hitti
Reviewed by Louise Chang
B)2005-2006 WebMD, Inc. All rights reserved

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