杏吧原创

PREGNANT women who take ecstasy risk causing long-term damage to the brains
of their children, a study on rats has suggested.

鈥淣ow we have a real identified risk, whereas before all we could do was
advise pregnant mothers not to take drugs as a precautionary measure,鈥� says
Charles Vorhees, head of the team that made the discovery at the University of
Cincinnati College of Medicine, Ohio.

鈥淭his is a real landmark study,鈥� says Lynn Singer, a paediatrics expert at
Case Western Reserve University School of Medicine in Cleveland, Ohio. 鈥淚t鈥檚 the
first developmental study suggesting ecstasy exposure can affect basic learning
辫谤辞肠别蝉蝉别蝉.鈥�

Vorhees鈥檚 team attempted to mimic in rats the effects of ecstasy on the most
important stages of human brain development in the last three months of
pregnancy.

They gave half the rats ecstasy twice a day for the first 10 days of life. At
this age, they are at the same stage of brain development as a human fetus
between 24 and 30 weeks old. The other half were given ecstasy when they were
between 10 and 20 days old, equivalent to the last six weeks of human pregnancy.
Other rats were given salt solution as a control.

When the rats reached maturity 60 days later, Vorhees gave them standard
tests to measure brain function. The only rats to underperform were those that
had received ecstasy 10 to 20 days after birth. This tallied with damage to the
hippocampus, the part of the brain vital for memory.

In one test to measure spatial awareness and sense of direction, the rats had
to locate a submerged platform in a pool. The rats who had received ecstasy
later in their development performed between 30 and 50 per cent worse than
controls. In people, this might manifest itself as a poor sense of direction,
says Vorhees.

In a second test to measure memory-dependent learning, rats had to swim
and climb their way out of a labyrinth of water channels. Again, those given the
drug later performed worst, making between 25 and 40 per more errors than
controls. In people, this might affect their ability to carry out sequences of
tasks, such as assembling flat-packed furniture or following a recipe.

鈥淲hat was surprising was that ecstasy has such a large effect,鈥� says Vorhees.
But when he looked at the brains of the animals afterwards he failed to find the
telltale ecstasy damage usually found in adult rats, which is caused by high
levels of the neurotransmitter serotonin.

Vorhees believes this may be because, in the developing brain, serotonin
helps brain cells to grow connections rather than acting as a neurotransmitter.
鈥淚t must work through a different pathway,鈥� he says.

Singer has done similar studies suggesting that cocaine use by pregnant
mothers impairs the intelligence of their children. She says that studies like
Vorhees鈥檚 in rats are usually a good indicator of what happens in people. She
and a group of British researchers at the University of East London are planning
a follow-up study in pregnant women who take ecstasy.