- Scientists found that rats lacking a brain receptor felt less attached to cocaine
- Since they had a pre-existing flow of excitement-triggering neurotransmitters, it limited cocaine’s power to induce a high
- It meant they were less likely to crave the drug after taking it
- The researchers at the NIDA said this offers a clear path to an addiction cure
People who lack a certain brain receptor are less likely to get hooked on cocaine, a study suggests.
Cocaine induces an addictive high by binding to receptors, triggering a rush of neurotransmitters such as dopamine and glutamates, which float around and excite synapses.
It may seem logical, therefore, to believe that people with more control of their receptors and neurotransmitters are less susceptible to the drug.
However, new research by the National Institute on Drug Abuse suggests people who have less control of these receptors are less prone to addiction.
That is because they have a pre-existing flood of glutamate, which limits cocaine’s power to deliver a neurological reward.
The researchers say their findings could pave the way to a drug to relax these receptors, making cocaine less addictive.
Researchers at the National Institute on Drug Abuse found rats were more prone to addiction if they lacked ability to control the neurotransmitter glutamate
Most addiction studies focus on how cocaine and other addictive drugs trigger the brain to release a rush of dopamine, which makes users feel a sense of euphoria.
Dr Xi looked at a different angle: glutamate, the other essential neurotransmitter, which is used for learning and communication in the brain.
To explore its role in addiction, they studied rats, looking at their control – or lack thereof – of glutamate.
They found that those who were missing a crucial neuroreceptor to control glutamate would not feel as stimulated by cocaine.
It meant they would take copious amounts of it to reach a high – but it did not leave a lingering desire for more.
The scientists then experimented by actively silencing the gene, mGluR2, which is responsible for making that receptor stronger.
As expected, the rats with a silenced gene were not enamored by the Schedule 2 drug.
‘The gene-knockout mice don’t enjoy much reward when they take the cocaine. So when the drug is available to them, the animals work to increase their intake to feel rewarded,’ said lead author Zheng-Xiong Xi, an addiction researcher at NIDA.
‘But when the drug is difficult to get, the reward isn’t worth it anymore, the animal just wants to quit.’
Xi said the findings show a clear path to a cure for addiction – to cocaine and other drugs.
‘Our work suggests that, if you could take a medicine to activate mGluR2 activity, then it would decrease or significantly inhibit both cocaine-taking and cocaine-seeking behaviors,’ Xi said.
‘It seems that mGluR2 may be a common target for treating addictions to many drugs.’