The antiepileptic property of the plant is, however, not substantiated experimentally yet. Vauquelin et al. observed that (±)tetrahydropalmatine binds to dopaminergic D1 and D2 dopaminergic receptors in membranes from human putamen (128). Hu et al. noted that intraperitonneal injection of tetrahydropalmatine, as well as D2 receptor antagonist spiperone, produced dose-dependent antinociceptive effects on the noci-ception of rats, and suggested that activating the spinal D2 receptor or blocking the supraspinal D2 receptor produces antinociception (132). In addition, tetrahydropalma-tine abrogates the increase of amygdaloidal release of dopamine in rats treated with 3 mg of picrotoxin per kilogram parentherally (133). The question arises, therefore, whether Stephania cepharantha Hayata is antiepileptic through inhibition of amygdaloid dopamine release or not, and if it is, what is the active principle?

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