Keyhan farhadi moghaddam - Medical student, Faculty of Medicine, Zahedan University of Medical Sciences; Zahedan, Iran
Parisa ebrahimi - Medical student, Faculty of Medicine, Islamic Azad university of zahedan; Zahedan, Iran
Mohammad reza shahraki - professor, Department of Medical Physiology, Faculty of Medicine, Zahedan University of Medical Sciences; Zahedan, Iran

Decarboxylated phytocannabinoids can activate endocannabinoid system via activation of cannabinoid receptors CB1 and CB2. Endocannabinoid system has interaction with opioid system. The aim of this investigation is studying the effect of interaction of decarboxylated phytocannabinoids with naloxone at systemic level on feeling .intensity of thermal and chemical pains and inflammatory paw edema In this experimental study, male Wistar rats (200-250g) were used. For studying the effect of interaction with opioid system, intraperitoneal administration of hexanic extract (50mg/kg), naloxone (2mg/kg) and co administration of extract and naloxone was performed. For to measure the thermal pain threshold used tail flick test and to measure intensity of chemical pain used formalin test. Paw volume was measured before and one hour after .sub-plantar administration of formalin using plethysmometer method in order to assess inflammatory edema I.p. co administration of extract and naloxone elevated thermal pain threshold (P<0.05) and reduced chemical pain (p<0.01) compared with i.p. injection of naloxone. Also Intraperitoneal administration of extract alone or .)in combination with naloxone reduced the inflammatory rat paw edema volume (p<0.001 As regards, naloxone attenuated anti-nociceptive effect of hexanic extract that suspected decarboxylated phytocannabinoids in extract via activation of CB1 and CB2 receptors interaction with opioid receptors in pain path way and part of effect of extract on pain applied via opioid receptors

Cannabis sativa, Cannabinoid receptors, opioid receptor, Naloxone, chemical pain