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IN SCIENTIFIC publishing, as in surgery, retraction is a traumatic but revealing process. This week, George Ricaurte and his colleagues at Johns Hopkins University, in Baltimore, were on the operating table. Almost a year ago, this team of neuroscientists published a paper in Science which showed that methylene-dioxy-methamphetamine—a recreational drug more commonly known as Ecstasy—killed off brain cells that produce and respond to dopamine. This chemical is a neurotransmitter (a molecule that carries signals from one nerve cell to another). A lack of it is involved in Parkinson's disease, which causes tremors and twitches. The paper sparked debate both in the laboratory, where many other researchers questioned its methods and findings, and in the wider world, where the opponents of Ecstasy seized on the results as further proof of the drug's dangerous effects.
In the current issue of Science, however, Dr Ricaurte and his team retract these results. The reason is painfully simple: they injected the wrong drug into the monkeys in their experiments. The mistake apparently emerged when the researchers tried, and failed, to reproduce their findings, and also tried to extend them by feeding Ecstasy to monkeys rather than injecting it, in order to mimic more closely the way humans take the drug. When they realised they were using a different batch of Ecstasy for this work, they went back to look at their older supply. Unfortunately, the original vials had been discarded, but they did have vials of another drug, labelled as methamphetamine (a similar, but not identical, molecule), delivered by the same supplier on the same day. When tested, these vials were found to contain Ecstasy, not methamphetamine, which suggests that the labels had been switched.
Dr Ricaurte retracts the findings of his original study (re-published by MDMA.net) in the current issue of Science. See also the work of Charles Grob and Andy Parrott.
Further proof came through animal testing. Although, like the vials, the monkeys used in the original experiments were long gone, some of their brains had been frozen for further research. When these were analysed, they were found to contain methamphetamine, not Ecstasy.
From
The Economist
Sep 11th 2003
http://mdma.net/toxicity/mixup.html
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