Abstracts

RATIONALE: Ginseng has been used as a folk medicine in far eastern countries for thousands of years. One of its pharmacological effects on the central nervous system is to modify the neurotransmitter-receptor systems. Recently, it was demonstrated that saponin elicited the inhibitory effect on electrically evoked response of CA1 region of rat hippocampal slices, suggesting that it could attenuate hyperexcitation of the neural systems (Lee [italic]et al[/italic]., Biol Pharm Bull. 2000;23:411). Therefore, we tested the potential inhibitory effect of saponin on epileptiform activity induced in rat hippocampal slices. The goal of this study is to further discuss the future direction for saponin research in epilepsy.
METHODS: Epileptiform activities were recorded in CA1 region of hippocampal slices from Sprague-Dawley rats using extracellular field potential recording with grass micropipette. To induce epileptiform activity hippocampal slices were perfused with Mg²⁺-free oxygenated artificial cerebrospinal fluid (aCSF) at 30[degree]C.
RESULTS: Within 20 min of incubation with Mg²⁺-free aCSF, spontaneous interictal bursts and ictal discharges were observed in slices from rats of postnatal days 11-14. Once stabilized, the duration of individual ictal discharge ranged from 5 to 80 s, occurring every 1 to 5 min. A subsequent treatment with 10 [mu]g/ml saponin for 10 min completely blocked interictal bursts and also reduced ictal discharges in amplitude, duration and occurrence rate by 91.1 [plusminus] 7.4%, 87.6 [plusminus] 10.4% and 85.5 [plusminus] 14.8% (n = 9), respectively. No differential effect of saponin was shown between tonic-type and clonic-type ictal discharges. One [mu]g/ml saponin treatment for 10 min was less effective (66.3 [plusminus] 15.7%, 76.9 [plusminus] 7.5% and 62.5[plusminus]12.5% reduction in amplitude, duration and occurrence rate, respectively, n = 3). In slices from 5-6 week old adult rats, epileptiform activities were mainly characterized by interictal bursts of 100-300 ms duration, which was also suppressed following perfusion of 10 [mu]g/ml saponin (97.2 [plusminus] 9.7% reduction in amplitude, n = 5).
CONCLUSIONS: These results demonstrated that ginseng total saponin, a major component of ginseng root, was very effective in controlling epileptiform activity induced by Mg²⁺-free aCSF in a dose dependent manner.
[Supported by:Inha University Grant 1996.]