[3H]-monoamine uptake inhibition properties of kava pyrones

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 [H-3]-noradrenaline. Uptake of [H-3]-noradrenaline was inhibited in the following order of potency: (+/-)-kavain = (+)-kavain > (+)-methysticine, whereas none of the kava pyrones efficiently blocked the uptake of [H-3]serotonin, The results indicate a pyrone-specific non-stereoselective inhibition of the [H-3]-noradrenaline uptake which might be responsible for or, at least, contribute to the psychotropic properties of kava pyrones.