What does it mean if you do not get drunk easily?

Answer 1

These are the main factors influencing inebriation from a given amount of alcohol:

1) Eating while drinking slows the absorption rate of alcohol into the bloodstream, and also dilutes it with other substances ingested, reducing the propensity to become drunk.

2) Since the human liver can convert ethanol (remove it from bloodstream) at a rate of about .015 of BAC per hour, if you do not exceed this absorption rate, you don't get drunk as easily.

3) Increased liver enzymes (such as alcohol dehydrogenase) can allow the liver to metabolize more ethanol at a given time, increasing the rate at which the liver converts ethanol to acetaldehyde, and reducing the blood alcohol concentration (reducing the blood sent into the brain). These enzymes are typically increased (upregulated) as a person drinks more alcohol. And this gives a person the majority of their tolerance to alcohol. However, this can also be genetic.

4) GABA receptor variation - some people are predisposed to Alcoholism due to variation in their genes that code for GABA (gamma-aminobutyric acid) receptors in the brain, which are responsible for anxiolytic (anxiety-reducing) and inhibitory effects of GABA, benzodiazepines (such as Xanax, Valium, etc.), and ethanol. For those that have "mutant" forms of GABA receptors, they may have reduced binding affinity or reduced activity in the presence of ethanol, which can make them more tolerant to ethanol.

5) GABA receptor downregulation/downmodulation - often times, however, excessive drinking over time will cause the brain to reduce GABA receptor density (decrease the number of GABA receptors), which reduces the effect that GABA, benzodiazepines, and ethanol have on brain cells...which causes a receptor-based, rather than metabolic, tolerance for ethanol.