en تخصصي Special پژوهشي Research Article <aside style="box-sizing: border-box; font-family: Lato, Arial; word-wrap: break-word; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; word-wrap: break-word; margin: 0px 0px 10px; font-size: 12px; text-align: justify;"><span style="box-sizing: border-box; word-wrap: break-word; font-weight: 700;">Background:</span>&nbsp;Our previous studies indicated that nanoparticles of magnesium oxide (nano-MgO) can affect some of morphine withdrawal signs such as anxiety, but their interaction with opioidergic system activity in depression- like behavior induced by morphine withdrawal is not clear.</p> </aside> <aside style="box-sizing: border-box; font-family: Lato, Arial; word-wrap: break-word; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; word-wrap: break-word; margin: 0px 0px 10px; font-size: 12px; text-align: justify;"><span style="box-sizing: border-box; word-wrap: break-word; font-weight: 700;">Objectives:</span>&nbsp;The present study aimed at investigating the effects of nano-MgO on depression induced by naloxone and morphine withdrawal in animals.</p> </aside> <aside style="box-sizing: border-box; font-family: Lato, Arial; word-wrap: break-word; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; word-wrap: break-word; margin: 0px 0px 10px; font-size: 12px; text-align: justify;"><span style="box-sizing: border-box; word-wrap: break-word; font-weight: 700;">Methods:</span>&nbsp;Adult male NMRI mice were divided in 2 main groups. For the control group, intraperitoneal (i.p.) injection of nano-MgO (1, 2.5 and 5 mg/kg) or naloxone (3 and 5 mg/kg) and coinjections of naolxone5 before and after nano-MgO2.5 mg/kg were done. The morphine withdrawal group received saline or nano-MgO 2.5, 5 and 10 mg/kg as acute (a single injection at the test day) and chronic injection (coinjected with morphine for 4 days). To develop morphine dependency, increasing doses of 20, 40, and 80 mg/kg morphine were injected subcutaneously for 4 days. Then, mice received a final morphine injection (40mg/kg) 3 hours prior to naloxone (5 mg/kg (i.p.)) on the test day. Depression- like behavior was assessed by the tail suspension test.</p> </aside> <aside style="box-sizing: border-box; font-family: Lato, Arial; word-wrap: break-word; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; word-wrap: break-word; margin: 0px 0px 10px; font-size: 12px; text-align: justify;"><span style="box-sizing: border-box; word-wrap: break-word; font-weight: 700;">Results:</span>&nbsp;Naloxone 3 and 5mg/kg induced depression (P < 0.05 and P < 0.01, respectively), while acute injection of nano-MgO2.5mg/kg after naloxone5 mg/kg improved depression (P < 0.01). Morphine withdrawal has induced depression in addicted mice (P < 0.05), while acute injection of nano-MgO2.5 mg/kg (P < 0.05) and nano-MgO 5 and 10 mg/kg (P < 0.01) reduced it.</p> </aside> <aside style="box-sizing: border-box; font-family: Lato, Arial; word-wrap: break-word; margin-bottom: 10px; font-size: 11px;"> <p style="box-sizing: border-box; word-wrap: break-word; margin: 0px 0px 10px; font-size: 12px; text-align: justify;"><span style="box-sizing: border-box; word-wrap: break-word; font-weight: 700;">Conclusions:</span>&nbsp;Nano-MgO can reduce depression- like behavior induced by naloxone and morphine withdrawal in animals probably by interaction with opioid receptors.</p> </aside> Depression, Naloxone, Nanoparticles, MgO, Morphine Withdrawal 119 124 http://ajnpp.umsha.ac.ir/browse.php?a_code=A-10-2-63&slc_lang=en&sid=1 Mahnaz Kesmati 1003194753284600292 1003194753284600292 No Professor of Physiology, Department of Biology, Faculty of Sciences, Shahid Chamran University of Ahvaz, IR Iran Mozhgan Torabi mozhgan.torabii@yahoo.com 1003194753284600293 1003194753284600293 Yes PhD Student of Animal Physiology, Department of Biology, Faculty of Sciences, Shahid Chamran University of Ahvaz, IR Iran Maryam Konani 1003194753284600294 1003194753284600294 No Master Student of Animal Physiology, Department of Biology, Faculty of Sciences, Shahid Chamran University of Ahvaz, IR Iran