New avenues for treatment of cocaine addiction

University of Canterbury discovery opens new avenues for treatment of cocaine addiction

April 27, 2014

Scientists of the University of Canterbury have discovered that by chemically activating a receptor in the brain they can eliminate cravings for cocaine.

The discovery has just been published in the official journal of the American College of Neuropsychopharmacology (www.nature.com/npp/), a leading publication in psychiatry.

The receptor in question is the trace amine-associated receptor 1 and is found in certain areas that appear to be very sensitive to drugs, Canterbury psychology researcher Dr Juan Canales says.

Cocaine addiction remains at epidemic levels in the United States and in some European countries but therapies to treat this condition are still ineffective. The Canterbury finding opens new avenues for the therapeutic treatment of cocaine addiction.

``It remains to be seen whether activation of this recently discovered receptor provides relief for other forms of addiction too, including alcohol, nicotine and even compulsive eating. This is something we are going to investigate in the near future,’’ Dr Canales says.

The market for cocaine in New Zealand is small and unpredictable. Methamphetamine, another stimulant, represents a much bigger problem.

Canterbury researchers have already conducted experiments to see if activation of the brain receptor is effective with methamphetamine.

``So far the results indicate that activation of the trace amine receptor completely eliminates the self-administration of methamphetamine in rodents as it does for cocaine. We will publish the full results soon.

``Cocaine and methamphetamine produce euphoric effects mainly through activation of a transmitter named dopamine. Dopamine is important for motivation, pleasure and well-being. The problem is that drugs like cocaine and methamphetamine cause a particularly powerful surge of dopamine in the brain.

``By releasing dopamine, drugs create a shortcut to get to the brain’s pleasure centres. Normally dopamine is released when we experience something really exciting. This is how the brain learns and changes our behaviour to produce those outcomes again. Dopamine signals reward in certain situations but is also a teaching signal.

``When cocaine and methamphetamine activate dopamine they fool the brain into thinking that they are really good, or better than anything experienced before but this is only an illusion.’’

The Canterbury research team led by Dr Canales has discovered that when the trace amine receptor is activated, cocaine is unable to release dopamine into the pleasure centres, which explains their findings.

They have also found that, after abstinence from chronic cocaine exposure, cocaine seeking disappears when the trace amine receptor is activated, preventing relapse.

Dr Canales’ postgraduate students are also involved in other addiction projects and work in with the Canterbury District Health Board as part of their research.
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