Journal of Research in Medical Sciences1735-199512420070828Effect of matricaria recutita on acute pain in the presence and absence of sex hormones190197ENMahnazKesmatiDepartment of Biology, Shahid Chamran University of Ahvaz, Ahvaz. mahnazkessmati@yahoo.comNedaBarfinejadHadiFathi Moghadam2007010620070514BACKGROUND: Chamomile is a beneficial herbal drug that is used as an anti-inflammatory, sedative and anti-allergic agent. The mechanism of action of matricaria recutita (MR), a specious of chamomile, in nociception in male and female animals is not fully understood. In this study, the sedative effect of a species of chamomile, MR, on acute pain was investigated in both male and female adult mice in the presence and absence of sex hormones.METHODS: Male and female NMRI mice weighing 28 ± 3 grams were used. Animals of each sex were divided into intact and gonadectomized groups. Intact group received saline or MR extract (10, 30, 50 mg/kg, intraperitoneally). Gonadectomized group contained two subgroups: a) group that received saline or MR hydro alcoholic extract (50 mg/kg, I.P.), and b) group that received sex hormones (testosterone in male mice and estradiol benzoate and progesterone in female mice), both with and without MR extract (50mg/kg, IP). The analgesia times in all groups were evaluated by hot plate test.RESULTS: MR increased analgesia time both in intact and gonadectomized male and female mice, but had no effect in the presence of pharmacological doses of testosterone (2 mg/kg, subcutaneous) in male mice, and estradiol benzoate (0.1 mg/kg, SC) and progesterone (0.5 mg/kg, SC) in female mice.CONCLUSIONS: It seems that MR can induce a pain-relieving effect with and without physiological doses of sex hormones in male and female mice, but sex hormones probably interact with its analgesic effect in their pharmacological doses.KEY WORDS: Matricaria recutita, pain, testosterone, estradiol benzoate, progesterone, hot plate.