Role of orexinergic receptors in the dentate gyrus of the hippocampus in the acquisition and expression of morphine-induced conditioned place preference in rats.

This study examined the effects of intra-DG orexin-1 (OX1) and orexin-2 (OX2) receptor antagonists on the acquisition and expression of CPP induced by morphine. Two separate cannulas were inserted bilaterally into the DG, and a CPP paradigm was performed. The CPP scores and locomotor activities were recorded using Ethovision software. The results showed that intra-DG microinjection of SB334867 as a selective OX1R antagonist (0.5, 2.5, 12.5 nM/0.5 µl DMSO) or TCSOX229 as a selective OX2R antagonist (0.5, 2.5, 12.5 nM/0.5 µl DMSO) before a morphine subcutaneous injection (5 mg/kg) during a three-day conditioning phase dose-dependently represses the acquisition of morphine-induced CPP in rats. Furthermore, these antagonists reduced the CPP scores in the expression phase. Consequently, it was established that orexinergic receptors in the DG are involved in the acquisition and expression of morphine-induced CPP.
PMID: 31711894 [PubMed - as supplied by publisher]

Source: Behavioural Brain Research - November 7, 2019 Category: Neurology Authors: Shirazy M, RayatSanati K, Jamali S, Haghparast A Tags: Behav Brain Res Source Type: research