Most of the alcohol we drink is broken down and processed by our livers – but there’s one part that lives in the brain.
And that could be what causes our drunken antics.
It’s early days yet, but this new research – coming out of the US and China – suggests that alcohol effects, like a loss of motor skills, can be attributed to an enzyme known as ALDH2.
The research so far has only been undertaken in mice, but what scientists have found is that while the liver does the heavy lifting in processing alcohol, the brain also has a role to play.
ALDH2 has always been found in the liver – science knows this – and this enzyme works to break down alcohol, turning it into acetate.
Acetate is the metabolite that’s been attributed to creating slurry, stumbling drunk behaviour.
It has always been thought the acetate was exclusively made in the liver, then travelled up to the brain through the bloodstream.
When it reaches the brain, it triggers gamma-aminobutyric acid (known as GABA), the principal inhibitory neurotransmitter, which as the name suggests, impairs all manner of brain functions.
But these scientists have found the enzyme ALDH2 also present in the brain, in particular the cerebellum, the part responsible for our balance and co-ordination.
Researchers removed the enzyme from the livers of their mice subjects, and found it did not stop them from losing control of their movements and balance while intoxicated.
But then they removed ALDH2 from the brain – bingo, no high acetate or GABA levels, and no staggering mice.
So what happens when we drink, is the acetate made in our liver makes its way to our brain, along with the acetate that’s already there.
Removing the acetate from the brain and the liver, and seeing different effects respectively, leads scientists to believe the compound behaves differently in each organ.
Therefore, alcohol’s effects may be determined in the brain and not the body, as previous research would suggest.
The data, published on Tuesday morning in the journal Nature Metabolism, suggest ALDH2 is an important, but previously under-recognised, target in the brain which determines the effects of drinking too much alcohol.
The authors suggest their findings could go so far as to treat alcohol use disorder, or alcoholism, which is when someone can’t control their drinking because of a physical and emotional dependence on alcohol.
“The possibility of brain alcohol metabolism has been a controversial topic within the field of alcohol research for several decades,” the authors wrote.
Their study challenges the long-standing idea that acetate is derived largely from the alcohol breaking down in your liver.
When in actuality, their data reveals this metabolite increases in the brain and ALDH2 in the cerebellum makes all the difference.