ABSTRACT
Traditionally, medicinal plants have been used to treat many diseases. To investigate the effects of different plants extract on cardiovascular system, five native southern Khorasan plants were used. Different concentration from the decoction of ziziphora, achillea millefolium [A.M] and aqueous extract of valeriana officinalis [V.O], viola and peganum harmala [P.H] were made]. Animals, Male Sprague Dawley rats [200-250 g, n=25] were anaesthetized with sodium thiopental [30 mg/kg, i.p.], then systemic arterial blood pressure [systolic, diastolic and mean] was measured. Mean arterial blood pressure was 140 +/- 5 mmHg. Intravenous administration of extract reduced the arterial blood pressure [eg. Administration of 0.03 mg/kg of aqueous extract of valeriana officinialis changed the blood pressure from 140 +/- 5 to 77 +/- 10 mmHg, P<0.0001]. There was a non-significant bradycardia with the administration of this extract. These results show that extract of ziziphora, V.O and A.M have hypotensive effects in the control rats and the most potent is V.O. By attention to non significant effect of these extract on heart rate, it is suggested that their hypotensive effect is induced by depletion in peripheral vascular resistance. For investigate of possible mechanism on vascular resistance, the isolated thorasic aorta rings in male rat were used. Therefore in another sets of experiments, after measuring blood pressure, chest was expanded and thoracic aorta was removed and cut into rings [3-4 mm]. Aqueous extract of V.O, in isolated aortic rings which was contracted by phenyl ephrin relaxed. Incubation of tissue with L-NAME [10[-5] molar] for 20 minutes significantly increased the response to different concentration of extract. Thus the vasodilatory mechanism of V.O is nondependent endothelium manner but it accomplish by vascular smooth muscle relaxation. In future, the effects of these extracts will be studied in the hypertensive rats, so that in case obtaining the same results and safety proof, these studied in the hypertensive rats, so that in case obtaining the same results and safety proof, these extracts on other systems, we can recommend take of these plant accompaniment by other treatment