This was a pretty cool study by undergraduate researchers at Greenville University and their advisor who is from Kiribati:
https://www.greenville.edu/news/stu...erest-from-international-scientific-community
It was the first to show that kavalactones have an effect on the action of the neurotransmitter acetylcholine (ACh), which is used by neurons to signal muscles to contract. They showed that kavalactones, and especially kavain, can cause paralysis in worms, from which they infer that it could somehow be inhibiting ACh transmission from the neuron to muscle.. It's interesting not so much because of the worms, but as a model for the effect of kava in humans, in whom ACh works the same way to control muscular movement... (Acetylcholine is also important in the brain. For example, nicotine works by stimulating acetylcholine receptors in the brain. But AFAIK kava's effect on ACh in the brain hasn't been studied...)