Withdrawal symptoms with cocaine decrypted

Researchers are deciphering the effects of cocaine withdrawal in the brain

12/09/2012

Researchers have decrypted the emergence of withdrawal symptoms after cocaine use. Washington State University researchers, in collaboration with researchers from the European Neuroscience Institute Göttingen, found out how cocaine use causes withdrawal symptoms in the brain.

Cannabinoid receptor 1 (CB1) plays a key role in cocaine dependence, according to research team led by lead author Bradley Winters of Washington State University. Like the scientists in the trade magazine „Proceedings of the National Academy of Sciences“ (PNAS), CB1 inhibits cocaine-induced hyperactivity in the brain-important part of the brain - the nucleus accumbens. However, this effect of CB1 also persists when the drug's effect is already abating. Accordingly, the activity in the nucleus accumbens is significantly reduced in cocaine withdrawal. The affected are unmotivated and depressed, which can trigger their desire for a new cocaine use. The current findings could make a significant contribution to the fight against cocaine addiction in the future, the researchers hope.

Cocaine alters the activity in certain brain regions
The cocaine has a significant impact on activity in certain brain regions, has long been known. The drug, for example, leads to increased activity in an area of ​​the forebrain (nucleus accumbens) that is critical to emotions and motivation. The researchers from Washington State University and the European Neuroscience Institute Göttingen have now investigated in experiments on mice, which effects are triggered at the molecular level by cocaine use and withdrawal in the brain. The focus of her research was cannabinoid receptor 1 (CB1), which inhibits communication between nerve cells. „Although expression of CB1 in the nucleus accumbens is low, manipulation of CB1 signaling associated with drug addiction and other psychiatric disorders triggers robust emotional / motivational changes“ from, report the researchers in the magazine „PNAS“.

Impotent and depressive with decreasing effect of cocaine
By consuming cocaine, the processes in the nucleus accumbens accelerate and displace the users „in a most satisfying emotional state“, Bradley Winters explained. In the experiments with genetically modified mice cocaine had also caused an increased release of CB1, apparently to counteract the hyperactivity in the brain of the gene mice. This is „as if you had to step on the brakes while driving down a steep hill“, Winters illustrated the effect. However, if the effect of the drug is diminished, the activity of CB1 does not normalize to the same extent. The brain can not release the brake, so that those affected „drive down a flatter hill, but only at two mph, because the foot is still on the brakes“, said the US neuroscientist in a Washington State University press release. Cocaine users therefore feel impotent and sad to depressed as the drug wears off.

Withdrawal symptoms increase the risk of relapse into cocaine addiction
The altered activity in their nucleus accumbens acts as a drag on the emotions and motivation of addicts to withdrawal. Affected people feel „terrible and and do not want to do anything, "said Winters, following the high-altitude flight, the crash and the feeling of the crash bring the cocaine consumers „back to the drug because you want to feel better again and the drug is the only thing they still feel motivated for“, continues the US researcher. However, based on current findings, it may be possible to develop methods "that limit the effect of the emotional crash and thus reduce the likelihood of relapse". (Fp)

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Image: D. Braun