Nigella sativa extract affects conditioned place preference induced by morphine in rats
Milad Anvari1, Atefeh Seddigh1, Mohammad Naser Shafei2, Hassan Rakhshandeh3, Amir Hossein Talebi1, Mohammad Reza Tahani4, S Mohsen Saeedjalali5, Mahmoud Hosseini1
1 Neurocognitive Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
2 Applied Physiology Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
3 Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
4 Department of Mechanic, Samen Technical Faculty, Technical and Vocational University, Mashhad, Iran
5 Department of ECE, Mashhad Technical Faculty, Technical and Vocational University, Mashhad, Iran
Department of Physiology, Neurocognitive Research Center, School of Medicine, Mashhad, University of Medical Sciences, Mashhad
Source of Support: None, Conflict of Interest: None
Objective: Neuroprotective, antioxidant, anticonvulsant, and analgesic effects of Nigella sativa (NS) have been previously shown. The interaction of NS with opioid system has also been reported. In the present study , the effects of NS hydro-alcoholic extract on the acquisition and expression of morphine-induced conditioned place preference (CPP) in rats were evaluated.
Materials and Methods: CPP was induced by injection of morphine (5 mg/kg, i.p.) on three consecutive days in compartment A of the CPP apparatus. Injection of NS extract (200 and 400 mg/kg, i.p.) 60 min before morphine administration on the conditioning days and 60 min before the post-conditioning phase was done for the evaluation of acquisition and expression effects, respectively. Conditioning effect of NS extract was also evaluated by injection of extract (200 or 400 mg/kg, i.p.) in the conditioning phase, instead of morphine in different groups. The difference in time which the animals spent in compartment A on the day before conditioning and the days after conditioning was determined and compared between groups.
Results: The time spent by the rats in compartment A in the morphine group was greater than that in the saline group (P < 0.01). Both doses of NS extract decreased acquisition of morphine-induced CPP (P < 0.01 and P < 0.001), but had no significant effect on the expression of morphine CPP. Higher dose of the extract (400 mg) showed a significant conditioning effect which was comparable to the effect of morphine.
Conclusion: The results of the present study showed that the hydro-alcoholic extract of NS has conditioning effect. It also decreased acquisition, but had no significant effect on the expression of morphine CPP.