Physiology and Pharmacology

en Effects of Papaver rhoeas extract on the expression and development of morphineinduced behavioral sensitization in mice Experimental research article Experimental research article H Sahraei1, Z Faghih-Monzavi2, SM Fatemi2, S Pashaei-Rad3, J Shams4 and H Ghoshooni11. Dept. of Physiology and Biophysics, Baqiyatallah (a.s.) Univ. Med. Sci., Tehran, Iran.2. Dept. Biology, School of Sciences, North Tehran Branch, Islamic Azad Univ. Tehran, Iran.3. Dept. Biology, School of Sciences, Shaheed Beheshti Univ., Tehran, Iran.4. Neuroscience Research Center, Shaheed Beheshti Univ. Med. Sci., Tehran, Iran.Abstract:Opioid addiction is one of the main problems for the health services. In the present study, the effects of water-alcoholextract of investigated.Mice became sensitized (5 mg/kg, once daily, for three consecutive days s.c.) or tolerate (50 mg/kg, twice dailyfor three consecutive days s.c.) to morphine and the extract before the morphine injection (acquisition) or on thetest day (expression) was administrated to them. In a pilot study, different doses of morphine and the extract wereadministered to the animals in order to evaluate if the drugs can produce any locomotion effects.Results showed that: subcutaneous (s.c.) administration of morphine (0.5-50 mg/kg) increased locomotoractivity in the animals. The response was more significant in dose 50 mg/kg of morphine. On the other hand,intraperitoneal (i.p.) administration of the plant extract (25, 50 and 100 mg/kg) did not show any effect. Dailyinjection of morphine (5 mg/kg s.c.) for three consecutive days and then five days resting induced sensitizationin the animals, so that the morphine sensitized animals showed an extra ordinary response to the ineffectivedose of morphine (5 mg/kg s.c.). Injection of extract (25, 50 and 100 mg/kg, i.p.) 30 min before the morphineadministration decreased the acquisition of morphine-induced behavioral sensitization. Administration of the Papaver rhoeas can reduced both the acquisition and expression ofKeywords: Morphine, Behavioral Sensitization and Tolerance, Mouse, Papaver rhoeasplant extract (25, 50 and 100 mg/kg, i.p.) 30 min before the test, also decreased the expression of morphineinducedbehavioral sensitization. Injection of morphine (50 mg/kg twice daily) for three consecutive daysinduced tolerance in the animals, so that the morphine tolerated animals did not show any response to theeffective dose of morphine (50 mg/kg s.c.). Injection of extract (25, 50 and 100 mg/kg, i.p.) 30 min beforethe morphine administration decreased the acquisition of morphine-induced tolerance. Administration of theplant extract (25, 50 and 100 mg/kg, i.p.) 30 min before the test, increased the expression of morphine-inducedbehavioral tolerance.It could be concluded that the extract of morphine-induced behavioral sensitization and also the acquisition of morphine tolerance but enhances theexpression of morphine tolerance in mice which may be true in the human.Papaver rhoeas on the expression and acquisition of morphine-induced behavioral sensitization were 151 158 http://ppj.phypha.ir/browse.php?a_code=A-10-74-1&slc_lang=en&sid=1