Explain Like I'm Five!
1) Why does kava cause euphoria?
2) Why does kava make you sleepy?
3) Why does kava make your muscles feel relaxed?
4) Why is kava not physically addictive?
We have threads on some of these already, notably
@infraredz very detailed explanation, but can it be broken down even simpler?
The complete work on studying kavalactones, their effects and interactions is not even close to being finished.
But as I can recall from the studies I have read;
Basically, your body always has endogenous chemicals in it that control how you feel. Some control happiness/sadness, wakefulness/sleepiness, confidence, fear, calm, pain perception etc...
When you take psychoactive drugs (chemicals) they either directly or indirectly influence those chemical to change balance and produce a different perceptible effect.
Some kavalactones like DMY and Methysticin are said to be MAO-B inhibitors, to inhibit MAO-B allows more Dopamine to flow into your brain without being broken down. Dopamine is responsible for things like mood, pleasure and pain. Dopamine rushes, at a much higher degree than kava typically provides, are responsible in large part for the effect you would get from many popular illegal drugs.
Kavain is said to be a quick acting anxiolytic. Some studies show a direct GABA influence, others show indirect responsibility through altering Sodium and Calcium channels in your brain. GABA is the thing responsible for you feeling anxious or calm...a drop in gaba creates fear and panic, extra gaba makes you calm and carefree. GABA is the main thing that gets altered by Benzodiazepines, alcohol, ghb, hypnotics etc... Isolated kavain may also somehow have a stimulating effect.
DHM is the most potent analgesic(pain killer) of the bunch, followed by DHK...but I'm not sure exactly what they influence to create the effect.
Yangonin is supposed to have no pain killing power, but may have a very slight affinity toward a certain cannabinoid receptor in the brain, which could make it responsible for some of kavas 'high' but not kavas anti-anxiety effect. Many kavalactones appear to have more than one effect, but each one will succeed at a certain aspect more than the next.
The answer to question #4 is:
kava is magic