Opioid receptors role on anti-nociceptive effects of the aqueous extracts of Melissa Officinalis in mice


Hossein Miladi Gorji 1 , * , Ali RashidiPour 2 , Abbasali Vafaei 3 , Abbasali Taherian 4


1 Instructor Department of Physiology, Instructor Department of Physiology, Semnan, Iran.

2 Professor Department of Physiology, Semnan University of Medical Sciences, Semnan, Iran.

3 Assistant Professor Department of physiology, Semnan University of Medical Sciences, Semnan, Iran.

4 Instructor Department of Physiology, Semnan University of Medical Sciences, Semnan, Iran.


Hormozgan Medical Journal: 10 (1); e89751
Published Online: March 05, 2006
Article Type: Research Article
Received: June 18, 2005
Accepted: March 05, 2006




Introduction: Melissa Officinalis (MO) overgrows in different parts of Iran. In
previous studies, ethanol extract of aerial parts (leaf & stem) of MO showed antinconvulsant
and sedative effects in rats. This study was designed to evaluate antinociceptive
effects in different doses of aqueous decoction extracts of MO and the
role of opioid receptors in rats.
Methods: In this experimental study, 63 male mice (weighing 25-30g) in Tail
Flick model were examined. Different doses of extract (5, 10, 25, 50 mg/kg IPMO)
were injected to the separate groups and saline (10ml/kg-IP) was injected
intrapeditoneal in control group. In four groups the role of opioid receptors
(Naloxone 2mg.kg) was designed to evaluate anti-nociceptive effects in the
aqueous decoction extracts of MO (5mg/kg) and 25 minutes after the injection the
anti-nociceptive effect was evaluated. Analysis of variance was used to analysis
the data.
Results: The results showed that average time of Tail Flick had significant
difference in two groups (P<0.0001) but the test groups had no significant
difference in different doses. Based on the results, naloxone caused reduction in
antinociceptive effects of 5 mg/kg Melissa Officinalis dose (P<0.0001).
Conclusion: It is concluded that the aqueous extract of MO has anti-nociceptive
activity which is not dose related, and is probably related to opioid receptors.
Determination of other receptors which may have anti-nociceptive activity needs
further investigation.


Receptors Opioid – Rats – Analgesics – Medicine Herbal

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