Role of orexin-1 receptors within the nucleus accumbens in acquisition and expression of methamphetamine-induced conditioned place preference in the rats

Background and Aim : • The orexins are hypothalamic neuropeptides and it has been revealed that orexinergic system, which has an essential role in learning, sleep, arousal, feeding, stress and pain processing, is also involved in addiction and reward-related behaviors. It has been found that both orexin-1 and −2 receptors are distributed throughout the reward circuitry such as nucleus accumbens (NAc), ventral tegmental area (VTA), hippocampus and prefrontal cortex and it has been found that orexins antagonists has been reduced the self-administration of heroin and ethanol.Accordingly, the present study aimed to survey the effects of the intra-NAc microinjection of SB334867 (a selective OX1R antagonist) in the acquisition and expression of CPP induced by methamphetamine in rats in order to extend our knowledge about the role of orexin receptors within the NAc.Methods : . fifty-three adult male Wistar rats (220–250 g) were entered in a CPP paradigm. Bilateral microinjections of different doses of SB334867 (1, 10 and 30 nM/0.5 DMSO) into the NAc were done 10 min before subcutaneous injection of methamphetamine (1 mg/kg) during 5-day conditioning (acquisition) phase. The CPP scores and locomotor activity of animals were recorded by video tracking system and Ethovision software.Results : As a result, we find out that the orexinergic receptors in NAc are associated with the acquisition and expression of methamphetamine-induced CPP.Conclusion : The antagonist may be a potential and promising therapeutic agent to suppress drug-related behaviors in the rats.

کلیدواژه ها:

Reward ، Orexin receptors ، Nucleus accumbens ، methamphetamine ، Acquisition ، expression ، Conditioned place preference ، Rat