Mahmoud Hosseini - Neurocognitive Research Center, School of Medicine, Mashhad University of Medical Sciences, I. R. Iran
Fatemeh Harandizadeh - Department of Physiology, School of Medicine, Mashhad University of Medical Sciences Mashhad, I. R. Iran
Saeed Niazmand - Neurogenic Inflammation Research Center, School of Medicine, Mashhad University of Medical Sciences, I. R. Iran
Mohammad Soukhtanloo - Department of Biochemistry, School of Medicine, Mashhad University of Medical Sciences, I. R. Iran

Objective: Nitric oxide (NO) plays an important role both as a consequence and as a cause of epileptic seizures.Regarding the central nervous system depressant effects of Achillea wilhelmsii (A. wilhelmsii), as well the effects of the plant on NO, this study was aimed to elucidatethe possible role for nitric oxide on the effects of hydroalcoholic extract of A. wilhelmsii on pentylenetetrazole (PTZ)-induced seizures. Materials and Methods: Fifty-six male Wistar rats were divided into 7 groups (n=8 in each group) and treated with (1) normal saline, (2) normal saline before pentylenetetrazole (PTZ, 90 mg/kg), (3-7) A. wilhelmsii extract (100, 200, 400, 800, and 1200 mg/kg) before PTZ. Latency to first minimal colonic seizure (MCS) and the first generalized tonic-clonic seizures (GTCS) as well as the mortality rate were recorded. The brain tissues were then removed for biochemical measurements. Fisher’s exact probability test as well as analysis of variance (ANOVA), followed by Tukey’s test were used for statistical evaluation. Results: Treatment with 100- 1200 mg/kg of the extract did not affect MCS latencies. 400 mg/kg of the extract prolonged GTCS latency (p<0.001), however, the lower and higher doses were not effective. Nitric oxide metabolites concentrations in the hippocampal tissues of the animals treated with 100, 200, and 400 mg/kg of the extract were increased compared with saline (pConclusion: The present study showed that hydroalcoholic extract of A. wilhelmsii affects NO metabolites in brain tissues as well the severity of seizures in PTZ-induced seizure model.

Achillea wilhelmsii, Hippocampus, Nitric oxide, Pentylenetetrazole, Rat, Seizures