Scientists have uncovered what cocaine does to the body and the brain to make it so addictive.
Researchers gave rats access to cocaine and allowed them to self-administer as much of the drug as they wanted for up to six hours a day over the course of five days. They then removed the rodents’ access to the drug for 14 or 60 days.
Following this period of abstinence, the scientists analysed the rats’ dopamine transporters and found they returned to normal form, as they had appear prior to taking any cocaine.
They then allowed the rats to self-administer one further dose of the drug. They found that even after 60 days of abstinence, the rats’ tolerance to cocaine was fully reinstated. Among a control batch of rats, who received no cocaine, a single dose did not have the same effects.
The results suggest a ‘priming effect’ takes places through administration of cocaine, which the brain never truly recovers from. It is thought this could explain why some adult humans with cocaine addiction find relapse is so common and severe.
The research was undertaken by scientists at Wake Forest Baptist Medical Center and has been published in the Journal of Neuroscience.
Lead study author Dr Sara R. Jones said of the findings: “Scientists have known for years that cocaine affects the dopamine system and dopamine transporters, so we designed our study to gain a better understanding of how tolerance to cocaine develops via the dopamine transporters.
“Even after 60 days of abstinence, which is roughly equivalent to four years in humans, it only took a single dose of cocaine to put the rats back to square one with regard to its' dopamine system and tolerance levels, and increased the likelihood of binging again. It's that terrible cycle of addiction.”
Cocaine is the second most widely used illegal drug in the UK, after cannabis.
9.4 per cent of all 16 to 59-year-olds have taken the drug at least once in their life time.
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