RESUMEN
Since long lasting administration of anti-seizure drugs produces undesirable side effects, many efforts have been made during recent decades to find and replace the chemical drugs by medicinal plants. The aim of present study was to study the antiepileptic [anti-seizure] effects of hydroalcoholic extract of Melissa officinalis on experimental epileptiform seizures, induced by pentylenetetrazol [PTZ] in Wistar rat. After normalization, rats in experimental groups 1, 2 and 3 were injected [i.p] 50, 80 and 120 mg/kg hydroalcoholic extract of Melissa officinalis, respectively. Control animals were injected extract solvent as the same manner. After 30 minutes all rats were injected [i.p] 80 mg/kg PTZ and then examined for epileptiform behaviors for the next 60 minutes. The rate of mortality during the next 24 hour was also recorded. In comparison with control group, in all experimental groups the latent period of tonic-clonic generalized seizure was significantly [P < 0.05] increased. Moreover, the mortality rate was decreased from 90% in control group to 30, 50 and 60% in experimental groups 1, 2 and 3, respectively. It can be concluded that hydroalcoholic extract of Melissa officinalis has potential sedative and anticonvulsant effects and probably exerts its effects through GABAergic system