Gabaergic system role in aqueous extract of Valeriana officinalis L. root on PTZ-induced clonic seizure threshold in mice

Pharmacognosy studies have shown that Valeriana officinalis L. roots containing significant amounts of free amino acids such as GABA and other substances like valeric acid and isovalerate. In this study, anticonvulsant effects of V. officinalis (VO) roots aqueous extract, using standard methods of chemical seizure caused by pentylenetetrazole (PTZ) in mice was assessed. To evaluate mechanisms involved in VO anticonvulsant effects, diazepam and flumazenil were used. After determining the seizure threshold in the control group, different doses of VO (0.25, 0.5 and 1 g/kg) were intraperitoneally (IP) administered and their effects on the threshold of PTZ-induced seizure were studied. Diazepam (1, 2 and 3 mg/kg) and flumazenil (1, 2 and 4 mg/kg) were injected intraperitoneally and the seizure threshold was determined, after which the different doses of the VO drugs were evaluated. The results showed that PTZ-induced seizure threshold in control mice was 35.52 ± 0.87 mg/kg. VO and diazepam were increased and flumazenil were decreased the threshold of PTZ-induced seizure. Also results showed that diazepam and flumazenil, respectively increase and decrease the effect of VO on PTZ-induced seizure. Changes in seizure threshold in this study indicate that probably the mechanism of VO anticonvulsant effects is due to the inhibitory GABA system, but this issue needs further investigations.   Key words: Valeriana officinalis, root, diazepam, flumazenil, PTZ, clonic seizure threshold.