Dopamine production is not behind vulnerability to cocaine abuse

Why do some individuals who strive medication battle with substance abuse whereas others do not? This query has lengthy puzzled scientists. A crew from the College of Geneva (UNIGE) explored the complicated interaction between persona traits and mind chemistry. The scientists studied the function of impulsivity and the manufacturing of dopamine—the so-called ”happiness hormone”—in influencing the chance of cocaine abuse.

These outcomes, published in eNeuro, supply new keys to understanding vulnerability to drug abuse, which may result in the event of extra focused interventions for individuals in danger.

When an individual consumes an addictive drug, his or her dopamine launch surges, making a “excessive” feeling. With repeated drug use, this dopamine launch drops, probably driving the particular person to extend drug consumption. This mechanism varies between people, with some displaying a better propensity to devour the drug whereas others do not. Nonetheless, the explanations for these variations are unknown.

Cocaine doesn’t have an effect on dopamine manufacturing capability

In a latest research, a UNIGE crew explored the complicated interplay between totally different impulsive behaviors, the manufacturing of dopamine and the usage of medication, extra particularly cocaine. Does an impulsive persona enhance the vulnerability to drug abuse? Does an impulsive particular person produce roughly dopamine? To search out out, the scientists studied two teams of rats, one made up extremely impulsive people, the opposite of much less impulsive ones. These animals have been educated to self-administer cocaine at a dose that triggers dopamine neuroadaptations with out harming their well being.

Scientists first educated the animals in a playing activity to measure two impulsive behaviors: impulsive motion—the shortcoming to manage computerized actions—and dangerous decision-making—the acceptance of extra threat when making selections. Scientists then measured the extent of dopamine synthesis utilizing a non-invasive neuroimaging method earlier than and after cocaine consumption within the two teams of rats. They discovered that impulsive motion, however not dangerous decision-making, predicted a better variety of cocaine injections and sooner cocaine use.

“Nonetheless, we noticed that there was no distinction within the capability to provide dopamine between the extremely impulsive and fewer impulsive animals. In different phrases, impulsivity and vulnerability to cocaine abuse won’t be linked to dopamine manufacturing, however to mechanisms controlling its launch,”‘ explains Ginna Paola Urueña-Méndez, Ph.D. scholar within the Division of Psychiatry and the Division of Primary Neurosciences within the College of Medication on the UNIGE, and first writer of the research.

The crew then assessed repeated cocaine use and its influence on dopamine ranges within the two teams of rodents. ‘”Till now, the concept that common cocaine consumption may scale back the flexibility to provide dopamine was accepted. Our outcomes contradict this assumption as each populations of rats retained the identical capability to provide dopamine, regardless of continual consumption,”‘ explains Nathalie Ginovart, Affiliate Professor within the Division of Psychiatry and the Division of Primary Neurosciences on the UNIGE College of Medication, who led this analysis.

Figuring out different mechanisms

These outcomes counsel dopamine synthesis might be not the principle driver of impulsivity or vulnerability to cocaine use. Additionally they contradict the speculation that cocaine use could immediately scale back the capability to provide dopamine.

This work represents a big advance in analysis into the chance of drug abuse. It opens the door to exploring different mechanisms that would clarify particular person vulnerability to medication. ‘”This variation in vulnerability could possibly be linked to variations within the relative reactivity of dopaminergic neurons, in order that sure stimuli, together with medication, are extra salient for extra impulsive animals,”‘ say the researchers. The crew is presently persevering with its analysis to evaluate how mechanisms controlling dopamine neuron reactivity affect vulnerability to abuse medication.