WASHINGTON (AP) _ Researchers who studied the effects of the drug Ecstasy on animals are retracting their report in a major scientific journal after discovering a labeling mix-up caused them to use a different drug.
Other studies also have reported on the brain hazards of Ecstasy, and the researchers said the problems with their work did not call into question the earlier findings.
Scientists at Johns Hopkins University reported in September 2002 that key neurons in the brains of squirrel monkeys and baboons were damaged when the animals were given doses of Ecstasy that mimicked those often taken by users of the drug during ``all-night dance parties.''
They said the study raised questions about whether Ecstasy, also known as MDMA, might hasten the onset of Parkinson's disease, a disorder triggered by the permanent loss of dopamine-producing nerve cells. It was those nerve cells that were reported to have been damaged by Ecstasy in the Johns Hopkins research.
In retracting the story, the journal Science said Friday that the researchers had discovered that labels on drugs supplied to them by an outside company were incorrect, and the animals had actually been given a different drug, methamphetamine.
Methamphetamine would be expected to produce the brain damage seen in the animals, the researchers said in their retraction.
Ecstasy is methylenedioxymethamphetamine. Both are forms of amphetamine but with different added chemicals and chemical action, said researcher Dr. Una McCann.
She explained that a bottle of MDMA and a bottle of methamphetamine were delivered to the lab the same day, from the same supplier, for different research purposes.
When the researchers had trouble duplicating some of their work they began to suspect problems, she explained. They had the bottle labeled methamphetamine analyzed by three labs and all reported it was pure MDMA _ and the brains of two animals that had died following the experiment were found to contain methamphetamine, not MDMA.
``It's a difficult situation. ... We pick up where we left off and see what we can do to prevent this from happening again, and we correct the record,'' McCann said.
She said the laboratory has developed a test for use in future studies to make sure it is using the actual drug that the research calls for.