[³ H]-Monoamine Uptake Inhibition Properties of Kava Pyrones

Abstract

Three kava pyrones, the natural compounds (+)-methysticine and (+)-kavain, and the synthetic racemate (±)-kavain, were tested concerning their action on in vitro uptake of monoamines in synaptosomes prepared from the cerebral cortex and hippocampus of rats. (±)-Kavain and (+)-kavain were found to potently inhibit the uptake of [³ H]-noradrenaline. Uptake of [³ H]-noradrenaline was inhibited in the following order of potency: (±)-kavain = (+)-kavain > (+)-methysticine, whereas none of the kava pyrones efficiently blocked the uptake of [³ H]-serotonin. The results indicate a pyrone-specific non-stereo-selective inhibition of the [³ H]-noradrenaline uptake which might be responsible for or, at least, contribute to the psychotropic properties of kava pyrones.