Mo'iety
Kava Enthusiast
Here's an interesting study from this past year: "Kavalactones from Kava (Piper methysticum) root extract as modulators of recombinant human glycine receptors".
It finds that kavalactones have an inhibitory effect at glycine receptors - a mechanism of action shared by compounds like caffeine[1] and strychnine. Kavain was found to be the most potent inhibitor (IC50 = 0.077), followed by yangonin (IC50 = 0.31). Inferring the subjective effects from in vitro studies like this is obviously highly speculative, but given that the two KLs most associated with "headiness" are the most potent, it seems plausible that this mechanism might come into play.
[1] Caffeine's main mechanism of action is as an adenosine receptor antagonist, though it's glycine antagonism might contribute to the "jitters".
It finds that kavalactones have an inhibitory effect at glycine receptors - a mechanism of action shared by compounds like caffeine[1] and strychnine. Kavain was found to be the most potent inhibitor (IC50 = 0.077), followed by yangonin (IC50 = 0.31). Inferring the subjective effects from in vitro studies like this is obviously highly speculative, but given that the two KLs most associated with "headiness" are the most potent, it seems plausible that this mechanism might come into play.
[1] Caffeine's main mechanism of action is as an adenosine receptor antagonist, though it's glycine antagonism might contribute to the "jitters".