'ONE DOSE DANGER' OF COCAINE

Cocaine makes the brain more responsive to addiction The first exposure to
cocaine could leave users vulnerable to addiction.

Using mice for testing, scientists found that just one single use of
cocaine could trigger a long-lasting surge of activity in the part of the
brain linked to the development of addiction.

And they said this could also be the reason why former drug users fall back
into addiction after just one relapse.

Drug groups are now hoping to dispel the widely held misconception that
cocaine is a safer, less addictive, drug than others.

Addictive

A spokeswoman for Addaction said that many drug users mistakenly thought
they were safe taking cocaine as a recreational drug, but that this new
study proved this was not the case.

"It is a general belief that cocaine is less addictive and that this is
assumed by users. So it is important to look at this study."

But Harry Shapiro, director of communications at the drug addiction group
DrugScope, said he would want to see more research before accepting the
findings of the research.

"Its impossible to make sense of a condition as complicated as addiction
from one study, particularly one conducted on mice. There is little
correlation between the brain patterns of mice and humans and I would
therefore be cautious about placing too much emphasis on a single piece of
research."

The research, published in Nature, showed that just one single use of
cocaine doubled the responsiveness of cells in the brain to the chemical
dopamine, which produces feelings of satisfaction and pleasure.

Scientists that for up to a week or ten days after taking the drug, the
brain was more sensitised to the pleasure of taking cocaine.

The research led by a team at University of California, San Francisco's
Ernest Gallo Clinic and Research Centre, provides the first direct evidence
that a single cocaine exposure - a recreational use - causes dramatic
changes in the brain to areas that cover learning and memory.

Dr Antonello Bonci, senior author of the paper and assistant professor of
neurology at the university said: "The study shows that the capacity for
strengthening connections between nerve cells - the basis for learning and
memory - can be usurped by drugs of abuse.

"The single exposure appears to hijack the brain's normal molecular
mechanisms of memory formation for around a week."

Other scientific research has shown that learning and memory are crucially
important in the development of addiction and also involve the activation
of the same brain cells - the dopamine neurons.

"Stunning"

Dr Mark Ungless, lead author of the paper, said the changes they had found
in brain activity were "stunning."

"What's so amazing is that nearly all dopamine neurons are affected by this
single cocaine exposure.

"This kind of response is rare, and would have a profound effect throughout
the brain particularly other areas involved in addiction."

The researchers said the drug patterns they had found could also apply to
other drugs as well as cocaine.

They now want to look into how the research can help develop treatments for
addiction.