Yasaman Pahlavan - Neuroscience Research Center and Department of Physiology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
Gholamreza Sepehri - Neuroscience Research Center and Department of Physiology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
Vahid Sheibani - Neuroscience Research Center and Department of Physiology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
Mohammadreza Afarinesh khaki - Neuroscience Research Center and Department of Physiology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran ۲ Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Morteza Gojazadeh - Departments of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Bahare Pahlavan - Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
Fereshteh Pahlavan - Faculty of Medicine, Ardabil Azad University of Medical Sciences, Ardabil, Iran

  Objective(s): The aim of study was to investigate the antinociceptive effect of intracerebroventricular (ICV) microinjection of Origanum vulgare (ORG) extract and possible involvement of opioid receptors.   Materials and Methods: Cannula was inserted into left ventricle of male rats. Five days after surgery Tail Flick Latency (TFL) was measured after ICV microinjection of, ORG (۱, ۳ and ۶ μg / rat). Effective dose of ORG was injected ICV in concomitant with morphine (۲ mg/kg, IP), naloxone (۲ mg / kg, IP) and saline (۰.۵ μl/rat) and TFL was recorded. Results: The co- administration of ORG extract with morphine showed a significant increase in TFL and naloxone, pretreatment significantly inhibited the antinociceptive activity of ORG and morphine. Conclusion: The aqueous extract of ORG possesses antinociceptive activities in the tail-flick test in a dose dependent manner. ORG - induced antinociception may have been mediated by opioid systems.

Intracerebroventricular Origanum vulgare Pain Rat Tail-flick test