Some people may be predisposed to becoming dependent on drugs as a result of having fewer of a certain type of brain receptor, a new study in Science has suggested.
Researchers at the Universities of Cambridge and Bristol have found that some individuals lack sufficient receptors for dopamine, a signalling molecule implicated in drug addiction.
A team at the Behavioural and Clinical Neuroscience Institute, led by Dr Jeff Dalley, found that impulsive rats had fewer dopamine receptors in the brain.
When the researchers offered cocaine to these rodents, they found that they were more likely to use the drug than rats with a normal level of receptors.
According to the researchers, this indicates that individuals with fewer dopamine receptors are more vulnerable to addiction.
Dr Dalley told the Daily Telegraph that the study had shown that the receptor is "diminished in number prior to taking to cocaine".
"This is important because much previous evidence in human cocaine addicts has likewise found reductions but it was impossible to know whether these changes pre-date cocaine use or emerge as a consequence of such use," he explained.
The researcher revealed that the next step will be to identify the gene or genes that cause the reduction in brain receptors - a finding which could provide an avenue for new therapies for drug addiction.
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