CHEMICAL HELPS COCAINE CAUSE HEART ATTACKS - STUDY

WASHINGTON, Aug 4 (Reuters) - German scientists said on Tuesday they had
found one reason why cocaine can cause a heart attack -- it causes
production of excess amounts of a chemical that can choke off blood supply
to the heart.

Doctors know all too well that cocaine can overstimulate the heart and
cause a heart attack. But they have not understood why -- or how to fight it.

Writing in the journal Circulation, Dr. Rainer Arendt of the University of
Munich and colleagues said they had pinned down one mechanism.

They said cocaine attacks the endothelium, which is the layer of cells that
lines the blood vessels. When attacked, these cells release a chemical
known as endothelin, which causes blood vessels to contract.

They tested the blood and urine of 12 people high on cocaine and 13
non-users. Levels of endothelin were three times higher in the cocaine users.

Tests on pig cells showed that cocaine causes so much endothelin to be
produced that blood vessels can eventually close off blood flow to the heart.

"This finding opens the opportunity to develop powerful drugs to fight
cocaine's effects," Arendt said in a statement.

"Not only will this provide a needed help in the occasionally difficult
medical therapy of treating cocaine-induced heart attack or stroke, but it
may prove to be important in understanding stress-related heart attacks and
cardiac arrests," he added.

"Cocaine seems to use the same pathways that are activated in the body's
response to stress."

Arendt's team tested two drugs that might counteract the deadly effects of
cocaine. They said the antipsychotic haloperidol, sold as Haldol,
eliminated the effects and another drug, ditolylguandine, helped.

Checked-by: Mike Gogulski