RESUMEN
BACKGROUND: Achillea wilhelmsii (A. wilhelmsii) is used in Iraninan folk medicine for the treatment of hypertension; also, in previous reports, the hypotensive and antihypertensive effects of this plant have been indicated. The aim of the present study is to investigate the vasorelaxant effect of the hydroalcholic extract of A. wilhelmsii and its underlying mechanisms in isolated rat aorta. MATERIALS AND METHODS: The effect of the hydroalcholic A. wilhelmsii extract was tested on the contractile response of Wistar rat aorta induced by potassium chloride (KCl) and phenylephrine (PE) using a pressure transducer that is connected to the PowerLab. RESULTS: The cumulative concentrations of A. wilhelmsii (0.5-8 mg/ml) induced a vasorelaxation both in endothelium-intact and endothelium-denuded aortas precontracted by high K(+) (6 × 10(-2) M) or 10(-6) M PE. A. wilhelmsii, at a concentration of 4 mg/ml, reduced Ca(2+)-induced contraction (P < 0.001 vs. control) after PE or KCl had generated a stable contraction in the Ca(2+)-free solution. Furthermore, after incubation with diltiazem, the vasorelaxant effect of A. wilhelmsii reduced in the endothelium-denuded aortas precontracted by PE or KCl (P < 0.001 vs. control). In contrast, A. wilhelmsii-induced relaxation was not affected by glibenclamide, BaCl2, ruthenium red, methylene blue, or heparin. CONCLUSIONS: The results showed that A. wilhelmsii had a vasorelaxation effect, which was not endothelium-dependent. The relaxation was mediated by inhibition of extracellular Ca(2+) influx through voltage- and receptor-operated Ca(2+) channels (VDDCs and ROCCs) in vascular smooth muscle cells.
RESUMEN
An important role for oxidative stress both as a consequence and as a cause of epileptic seizures has been suggested. Since Achillea wilhelmsii (A. wilhelmsii) has been considered to have the antioxidant effects as well as central nervous system depressant properties, the anti-seizure effects of the plant extract in addition to its effects on brain tissues oxidative damage were investigated in pentylenetetrazole (PTZ)-induced seizures model. Male Wistar rats were divided into 5 groups: (1) Control, (2) PTZ, (3-5) A. wilhelmsii extract groups (AWE). The animals in groups 2-5 were treated with saline or AWE (100, 200 or 400 mg/kg) before single injection of PTZ (90 mg/kg). Latency to first minimal clonic seizure (MCS) and the first generalized tonic-clonic seizures (GTCS) were recorded. The brain tissues were then removed for biochemical measurements. MCS latencies in extract treated groups were not different from PTZ group. The animals treated by 200 mg/kg of AWE had a significant higher GTCS latency in comparison with PTZ group (P < 0.001). The MDA levels in PTZ group were significantly higher and the total thiol concentrations were lower than control animals. Pretreatment with all 3 doses of the extract resulted in a significant reduction in the MDA levels (P < 0.05, P < 0.01 and P < 0.001) and a significant elevation in total thiol concentration, as compared with PTZ group (P < 0.05 and P < 0.01). The present study showed that the hydroalcoholic extract of A. wilhelmsii possesses an antioxidant effect in the brain in PTZ induced seizure model.