Behavioral Consequences of Alcohol Come from Your Immune System
Actors trying to depict a drunken individual will often stagger and stumble around and slur their speech in order to communicate intoxication. It is universally recognized as drunken behavior, but only recently have the “sloppy drunk” behaviors been explained as immune system-induced responses to alcohol intake.
A team of scientific researchers at Adelaide University in Australia recently published the results of a study which indicates that such behaviors have a direct link to the body’s immune responses. The study has been printed in the British Journal of Pharmacology. Study findings indicate that alcohol signals rapid changes in the brain’s immune system, decreasing behavioral control.
Lab mice were genetically manipulated by blocking immune system proteins known as TLR4 (toll like receptor 4). The protein was deactivated in mice that were then given a shot of alcohol and observed for behaviors associated with drunkenness. Mice with blocked TLR4 responses also exhibited reduced behavioral effects from alcohol. This was measured in terms of how long the drunken mouse was able to remain perched atop a rotating rod and how long it exhibited signs of sedation.
In both cases, the mice with inactive TLR4 proved to be resistant to the behavioral effects of drinking when compared to mice without the inhibitor. Of course, in both instances, the mice are still drunk; only their drunken behavior is affected.
The TLR4 protein functions as a switch in activating the body’s immune system. The body has automatic immune responses such as fever and inflammation which are triggered to fight infection. When the TLR4 switch is thrown, immune cells within the brain, known as glia, signal the inflammation response. It is believed that triggering inflammation actually produces the stumbling and slurring associated with intoxication.
The Adelaide team believes their research should transfer to humans and could have several possible applications. They suggest that chronic alcohol abuse might be treated with medications blocking TLR4, and say even short-term consequences such as acute overdose may benefit from deactivating the protein. Furthermore, the study could prove helpful in determining people at risk for long-term damage to the brain from sustained alcohol abuse.
Sedation and inhibited muscle coordination are known side effects of over-indulgence in alcohol. Those involved with this study suggest that alcohol-induced sedation and diminished motor function are likely responsible for traffic deaths.
Researchers from the Adelaide University team commented on the remarkable fact that despite thousands of years of human experience with alcohol consumption, and the decades dedicated to investigating its effect on nerve cells, so much of how alcohol works is yet to be fully understood.