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Background and Objective: Several studies have shown that inhalation of Lavandula angustifolia L. (Lavender) reduces hypertension, while systemic effects and mechanism of action of lavender oil on blood pressure is not clear. This study was carried out to evaluate the effect of intravenous and ntraperitoneal injection of Lavandula angustifolia L. oil on normal blood pressure in male rats. Methods: In this experimental study, 70 male Wistar rats were randomly allocated into 10 groups (n=7). Following anesthetizing the animals with sodium thiopental, femoral artery and vein were cannulated respectively for recording blood pressure and injection of Lavandula angustifolia L. oil. Lavender oil or its vehicle (Propylene glycol) was injected by intravenous (25, 50 and 100 mg/kg/bw) or intraperitoneal injection (500mg/kg/bw). For the evaluation of the mechanism of Lavender oil, L-NAME (4mg/kg/bw), atropine (1mg/kg/bw), indomethacin (5 mg/kg/bw) or saline was injected intraperitoneally before intravenous administration of Lavender angustifolia L. oil. Results: Intravenous injection of Lavender oil of 25 and 50 mg/kg/bw reduced arterial blood pressure in compare to control group (P<0.05) and dose of 50 mg/kg/bw was more effective than dose of 25 mg/kg/bw (P<0.05). 100 mg/kg/bw of Lavender angustifolia L. oil caused serious fall of blood pressure and resulted in animal death. Intraperitoneally injection of Lavender angustifolia L. oil at dose of 500 mg/kg reduced arterial blood pressure that this reduction was longer than intravenously administration of Lavender oil (P<0.05). Intraperitoneal injection of L-NAME, atropine or indomethacin had no significant effect on baseline of blood pressure and hypotensive effect of Lavender angustifolia L. oil. Conclusion: Intravenous injection of Lavandula angustifolia L. oil in doses of 25 and 50 mg/kg/bw reduced arterial blood pressure in rat, but intraperitoneally injection of Lavender oil at dose of 500 mg/kg/bw prolonged the reduction of blood pressure in animals.

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Several medicines are used in the nervous system disorders. Since there are several adverse effects of neurological medicines are reported, traditional and complementary medicine itself as new alternative regiment, which require further knowledge about the herbal medicine which the core center of complementary medicine. Lavandula angustifolia with the formal name of Lavandula Officinalis has many effects including widespread effect on central and peripheral nervous system, including anti-inflammatory, anti-apoptosis, antioxidant, antimutant, and neuroprotective effects. It shows analgesic effects and can alleviate pain, tolerance and dependency similar to morphine. Lavandula angustifolia has anti - inflammatory effect. Also this plant affects on cellular mechanisms like oxidative reactions (decrease of oxidative stress), apoptosis (anti - apoptosis), and nitric oxide production decrease of no production), anti - mutation and anti - cancer by this plant is reportd. It seems that effects of Lavandula are mediated through Calcium-Calmodulin and its kinase dependent.