Researchers in Sweden and the United States suggest that this might be the case after studying alcohol addiction in rats.
They found that the rats that became addicted had an impaired brain mechanism similar to that seen in postmortem brain tissue from humans addicted to alcohol.
The faulty mechanism is a failure to clear away a substance known as gamma-Aminobutyric acid (GABA) that inhibits signaling around neurons, or brain cells, in the central amygdala.
The amygdala is a region of the brain concerned with emotion, learning, memory, and motivation.
The scientists report their findings on alcohol addiction trends in a paper now published in the journal Science.
Disrupted ‘motivational control.’
The authors explain that of people who are exposed to alcohol, around 10–15 percent “develop alcohol-related problems.”
These alcohol news state that a similar proportion (15 percent) of the rats exposed to alcohol persisted with alcohol-seeking and became addicted.
The rats continued to dose themselves with alcohol even when a “high-value” option, such as sugared water, was made available.
Most of the rats switched over to sugared water when given the option, but the persistent minority continued to dose themselves with alcohol. This was in spite of the fact that pressing the lever to get the substance also delivered a slight electric shock to the paw.
The team observed that the alcohol-seeking animals behaved similarly to humans addicted to alcohol. The rodents were highly motivated to get alcohol, even though there were negative consequences and other reward options.
“We have to understand that a core feature of addiction is that you know it is going to harm you, potentially even kill you. Nevertheless, something has gone wrong with the motivational control and you keep doing it.” This alcohol addiction news confirmation came from senior study author Markus Heilig, a professor in clinical and experimental medicine at Linköping University in Sweden,
Signaling problem in the amygdala
In the same alcohol abuse news, the researchers reported that when they looked inside the rats’ brains, they discovered what might be disrupting the “motivational, control.” First, they looked for differences in gene expression in different parts of the brain. The most significant differences were in the amygdala.
They revealed that the gene that codes for a protein called GAT-3 was expressed at much lower levels in the amygdala of the rats that continued to choose alcohol compared with the rats that switched to sugared water.
GAT-3 is a “transporter” protein that helps to clear away GABA from around neurons. Studies have also revealed that rats that become addicted to alcohol seem to have altered GABA signaling.
To confirm that the GAT-3 gene was at fault, the scientists ran another experiment in which they silenced GAT-3 in the rats that had switched over to sugared water in preference to alcohol.
The effect was striking: the GAT-3 silenced rats began to behave similarly to their alcohol-seeking counterparts. When they were again given a choice between dosing themselves with alcohol or sugared water, they chose alcohol.